Poor throttle response with Dellorto DHLA carbs
Discussion
Hi Dave
What championship did that MGB engine of yours win? Long time ago mind you
We have engines dynoed and agreeing with our Dynocom rollers about 175-180, about 150-155 at the wheels (4th gear) without highlift rockers and on single 48 webers not split, this is 1840 or 1950. We have a customer with a posh USA built dry sumped MGB engine at 1950 cc making 190 at the engine. This is split carbs and posh internals and makes peak at 6300 at the wheels. A Dutch customer has hit 200 plus at the flywheel with roller cam followers. These are all with CI heads.
Just noticed your post about rally Pintos, you are way off the mark, we dynoed a Holbay Rally engine at 205 at the wheels, this was 231 on Holbays engine dyno, a lot more than 180!
Peter
What championship did that MGB engine of yours win? Long time ago mind you
We have engines dynoed and agreeing with our Dynocom rollers about 175-180, about 150-155 at the wheels (4th gear) without highlift rockers and on single 48 webers not split, this is 1840 or 1950. We have a customer with a posh USA built dry sumped MGB engine at 1950 cc making 190 at the engine. This is split carbs and posh internals and makes peak at 6300 at the wheels. A Dutch customer has hit 200 plus at the flywheel with roller cam followers. These are all with CI heads.
Just noticed your post about rally Pintos, you are way off the mark, we dynoed a Holbay Rally engine at 205 at the wheels, this was 231 on Holbays engine dyno, a lot more than 180!
Peter
Edited by PeterBurgess on Wednesday 4th December 12:28
Talk about synchronicity! Carl Norris just popped in from NMS next door, he reminded me of the 2188cc engine we tested for him, 300 degree cam and a pair of 48s, made 211 at the wheels and 31 bhp losses( big slicks!) = 242 at engine, he reckoned about 15 more to come with 320 degree cam, phew!
Peter
Puma,
I don't have quantified data to support Peter's measurements, but experience (on private roads, evidently) shows that my car is significantly faster than other MGs who are modified and rolling roaded independently, one of which a well-developed rally car.
(fwiw, my experiences with Peter were so positive that I bought cylinder heads for my MGB GT V8 from him as well)
I don't have quantified data to support Peter's measurements, but experience (on private roads, evidently) shows that my car is significantly faster than other MGs who are modified and rolling roaded independently, one of which a well-developed rally car.
(fwiw, my experiences with Peter were so positive that I bought cylinder heads for my MGB GT V8 from him as well)
Google Keith Franke and join his sidedraft weber Yahoo group .
Keith is a lotus owner who has spent the last few years analysing and modifying side draft carburettors and produced sets of 'hypo jets' and o-tubes and other techniques in order to overcome various shortcomings of carburettors at the progression phases between the idle circuit, the progression circuit and the pump circuit.
Some very interesting solutions and not particularly costly or difficult to implement. I think there are some UK owners who have installed his stuff with good results.
I will be doing so in the new year.
Keith is a lotus owner who has spent the last few years analysing and modifying side draft carburettors and produced sets of 'hypo jets' and o-tubes and other techniques in order to overcome various shortcomings of carburettors at the progression phases between the idle circuit, the progression circuit and the pump circuit.
Some very interesting solutions and not particularly costly or difficult to implement. I think there are some UK owners who have installed his stuff with good results.
I will be doing so in the new year.
PeterBurgess said:
Hi Dave
What championship did that MGB engine of yours win? Long time ago mind you
I didn't say it won a championship. I said it set several new circuit records. At least four I was told about but maybe more. As far as I recall it was class B (fully modified 1950cc MGBs) of the MGB/C/GT/V8 championship and I think the year was 1992 because I built the engine in September 1991. I'm sure the results will still exist somewhere but I don't have them anymore. Phil Conn was the customer and he told me he'd raced in that class for seven years without ever winning a single race. He could never beat someone called Peter Hall and another guy whose name I forget. With the new engine I believe he won every race he entered for the first half of the season, setting track records at most of them until another competitor offered him so much for the car he decided he couldn't refuse and sold it. What happened after that I have no idea. I remember being a bit miffed because I'd just put a hotter cam and some other bits in it and only charged for the parts element because his results were acting as such a good advertisement. Tight git didn't even buy me a beer for doubling the value of his car.What championship did that MGB engine of yours win? Long time ago mind you
I did later build a close duplicate of the first engine for a guy called Geoff Pyke who had at various times in the hunt for more power tried one of your race heads and another from Peter Hall on his engines. I got to flowtest both of those old heads of his which was interesting. You might even still have your own flow test sheet on that head of yours if you keep records that far back. I can certainly tell you what it flowed on my bench. It had 43mm inlet valves as did the Hall one if that helps you recall.
All I remember about that second engine was that the guy's mechanic blew it up before it had even raced when a nut from the air filter box he'd cobbled up got sucked into it when it was being run in and he had to rebuild it himself. I have no idea what sort of a job he made of that or what damage it did to my cylinder head. Then in the first race Geoff ever entered with it he went into the back of a stationary Aston Martin at about 70 mph which had stalled on the grid several places in front of him and shortened both cars by a considerable amount! I remember him telling me the front of his own car had ended up very close to the back of the driver's seat of the Aston, luckily without killing either of them! I think that might have been the end of both the engine and his racing career but couldn't swear to it. That engine certainly didn't lead a charmed life.
That was it with MGB engines for me. Horrible big old lumps of cast iron that were a struggle to move around the workshop single handed. I only really did the first one to prove a point to both myself and someone else I once knew quite well
Edited by Pumaracing on Thursday 5th December 03:36
Of interest Dave, as you say your engine DID NOT WIN ANY CHAMPIONSHIP which kind of implies you ‘talk the talk but don’t walk the walk’.
I feel you are living in the past, speaking of which do you remember our Race B going straight by your Race B at Donnington? You weren’t very amused mind you, if your engine was making more flow and more bhp than ours Pete Hiley must have driven his pants off to overtake Phil in a straight line.
Interesting you testing one of our heads from 20 years ago, good job we progress year on year isnt it? We run 45mm inlet valves these days and 40 mm inlet ports to keep ‘em revving.
Now, you can attack me, my flow bench, my old Clayton Rolling Road and my Dynocom Rolling Road all you want but, we have won MGB Champinships since 1989 and every year since, which is maybe why Veloce approached me to write a B tuning book and not yourself?
I attach a graph to show you the perils of assuming one has got the bestest/flowingest head in the world.
We ran a TVR 1840 MSX webered full race car on the dyno blue power line, made 133 at wheels and 28 bhp losses, pretty close to the max you claim of 160ish....161 in fact. We said this was poor so we got the head to check over, now this head had come from a respected head modifier in the States and was the dogs according to the superflow type numbers predicting max flow etc etc....you get the drift, obviously this guy was like you Dave and thought 160 bhp was good for a B and on the limit. We fettled thehead nearer to our race spec and you can see the results from the brown iine, same bottom end power till 4000rpm when our work showed its worth.....151 at wheels + 28 = 179 bhp at engine, a fair amount more than the 161bhp of the dogs head from the USA! In the end the customer paid for a head from scratch from us and we boosted power everywhere giving 184 at the engine, now then , we were not convinced he had the best cam in the car.....who knows what bhp the engine could have made with a better cam? Just to state all that was altered was head work and figures best I could get on rolling road for each setup.
We live in the real world out on the race track, warts and all, not armchair tuning. Did you know of Roy McCarthy, sadly passed away, now his B engines made more than ours, cost three times more and needed three builds a season but still made about 10 more than ours made....I can admit it, can you Dave?
When I get to work I will see if I can dig out a sheet with engine dyno figures from Agra testing one of our Fast Road MSX heads on a 1950 B engine. From early 90s but hidden away somewhere, I think it went quite well though.
Peter
I feel you are living in the past, speaking of which do you remember our Race B going straight by your Race B at Donnington? You weren’t very amused
mind you, if your engine was making more flow and more bhp than ours Pete Hiley must have driven his pants off to overtake Phil in a straight line.Interesting you testing one of our heads from 20 years ago, good job we progress year on year isnt it? We run 45mm inlet valves these days and 40 mm inlet ports to keep ‘em revving.
Now, you can attack me, my flow bench, my old Clayton Rolling Road and my Dynocom Rolling Road all you want but, we have won MGB Champinships since 1989 and every year since, which is maybe why Veloce approached me to write a B tuning book and not yourself?
I attach a graph to show you the perils of assuming one has got the bestest/flowingest head in the world.
We ran a TVR 1840 MSX webered full race car on the dyno blue power line, made 133 at wheels and 28 bhp losses, pretty close to the max you claim of 160ish....161 in fact. We said this was poor so we got the head to check over, now this head had come from a respected head modifier in the States and was the dogs according to the superflow type numbers predicting max flow etc etc....you get the drift, obviously this guy was like you Dave and thought 160 bhp was good for a B and on the limit. We fettled thehead nearer to our race spec and you can see the results from the brown iine, same bottom end power till 4000rpm when our work showed its worth.....151 at wheels + 28 = 179 bhp at engine, a fair amount more than the 161bhp of the dogs head from the USA! In the end the customer paid for a head from scratch from us and we boosted power everywhere giving 184 at the engine, now then , we were not convinced he had the best cam in the car.....who knows what bhp the engine could have made with a better cam? Just to state all that was altered was head work and figures best I could get on rolling road for each setup.
We live in the real world out on the race track, warts and all, not armchair tuning. Did you know of Roy McCarthy, sadly passed away, now his B engines made more than ours, cost three times more and needed three builds a season but still made about 10 more than ours made....I can admit it, can you Dave?
When I get to work I will see if I can dig out a sheet with engine dyno figures from Agra testing one of our Fast Road MSX heads on a 1950 B engine. From early 90s but hidden away somewhere, I think it went quite well though.
Peter
Edited by PeterBurgess on Thursday 5th December 06:54
Hi Dave
As promised, now I am at work, I attach a pic of the engine test sheet.
The engine was 1950 with our Fast Road MSX head and race cam and a big bore (primary) ex system, good shape as no carbs in the way on MSX head on B. Built by Cameron Gilmour Bumper to Bumper.Twin 45 DCOEs.Test Date 19/04/02......not 90s like I remembered!
Figures 4% for temp and pressure by Agra Engineering.Dyno testing totally independant of me, just my Fast Road MSX head!
RPM BHP
3000 60
3500 72
4000 95
4500 121
5000 140
5500 154
6000 165
6500 171
7000 180
Not bad eh? And 20 more than the 160 max you reckon! Ball park same as we got with the TVR showing our Dynocom not that far out for accuracy? Mind you head better spec on TVR but less good cam than the Agra tested one.
Looking at my records, if you had the success you say in 1992, Peter Hiley was the Championship Winner as he won the Road Modified Class so he must have beaten beat Phil in 1992 so I don't quite see what point you proved or achieved?
Peter
As promised, now I am at work, I attach a pic of the engine test sheet.
The engine was 1950 with our Fast Road MSX head and race cam and a big bore (primary) ex system, good shape as no carbs in the way on MSX head on B. Built by Cameron Gilmour Bumper to Bumper.Twin 45 DCOEs.Test Date 19/04/02......not 90s like I remembered!
Figures 4% for temp and pressure by Agra Engineering.Dyno testing totally independant of me, just my Fast Road MSX head!
RPM BHP
3000 60
3500 72
4000 95
4500 121
5000 140
5500 154
6000 165
6500 171
7000 180
Not bad eh? And 20 more than the 160 max you reckon! Ball park same as we got with the TVR showing our Dynocom not that far out for accuracy? Mind you head better spec on TVR but less good cam than the Agra tested one.
Looking at my records, if you had the success you say in 1992, Peter Hiley was the Championship Winner as he won the Road Modified Class so he must have beaten beat Phil in 1992 so I don't quite see what point you proved or achieved?
Peter
Edited by PeterBurgess on Thursday 5th December 08:44
Oh dear I seem to have hit a nerve, although that's never difficult to do with you. Firstly I never went to Donnington to watch Phil's MGB and have certainly never seen you at any race track ever so please don't just make sh11te up out of thin air Peter. That's a hell of a selective (defective?) memory you have there if you say you saw someone who wasn't even there being not amused by something he couldn't possibly have seen, if it even happened. I've only been to Donny once in my life and that was to watch my Fiestas racing. Phil had long since sold his car by then.
That name Pete Hiley does now ring more of a bell. It might have been him and Pete Hall that were the two people Phil told me he'd previously struggled to beat. Names are not my strong point, especially after so many years and of people I never met.
Pete, I have no idea how many bhp your engines were producing back when I built my MGB ones or whether you think you can get more out of them these days. All I know is Phil went from being 2 seconds a lap slower than Hall or Hiley at the end of one season to 2 seconds a lap faster than either of them at the start of the next. Maybe he ate lots of spinach over Xmas and it was nothing to do with the new engine at all
FYI Phil's engine had 45.7mm inlets. After lots of measuring that was the largest I could squeeze into the 1950cc bore size and even then it meant offset boring and dowelling the head in place to control the clearances. That was the only fancy stuff in the engine. Phil was so sick of his previous engines blowing up and having no spread of torque he just wanted something reliable and easy to drive. Piper BP300 rally cam, (later changed to a BP320), modest 11.4:1 CR, he already had nice alloy 1.625 ratio roller rockers, stock Payen head gasket and studs, stock lifter bore sizes. Pretty basic stuff really. Bigger lifters, more CR and valve lift/acceleration would have been nice if funds had allowed more high tech internals. The stock head studs were certainly rather limiting and apparently made out of something akin to chocolate but they just coped with 60 ft lbs (10 up on stock) and fortunately did the job.
Not too much point going into any depth on flow figures because your bench doesn't read the same as anyone else's but at 550 thou lift your 43mm inlet flowed 156 cfm compared to 170 cfm for the best port on my 45.7mm race head. I suspect that would equate to about 180 cfm on your own bench from the calibrations I've done. What I will say is your head flowed exceptionally well between 150 and 350 thou. More than I could ever achieve without sacrificing high lift flow but then it's getting that trade off right that's so critical.
On the second engine after a bit more flowbench time I came down to 45mm on the inlets to enable slightly larger exhausts to be fitted as I found that last 0.7mm on the inlet valves wasn't producing any more flow and was creating more clearance problems than it was worth. So after 30 odd years of building those awful things you've probably finally ended up at the same place I started Good lad.
That name Pete Hiley does now ring more of a bell. It might have been him and Pete Hall that were the two people Phil told me he'd previously struggled to beat. Names are not my strong point, especially after so many years and of people I never met.
Pete, I have no idea how many bhp your engines were producing back when I built my MGB ones or whether you think you can get more out of them these days. All I know is Phil went from being 2 seconds a lap slower than Hall or Hiley at the end of one season to 2 seconds a lap faster than either of them at the start of the next. Maybe he ate lots of spinach over Xmas and it was nothing to do with the new engine at all
FYI Phil's engine had 45.7mm inlets. After lots of measuring that was the largest I could squeeze into the 1950cc bore size and even then it meant offset boring and dowelling the head in place to control the clearances. That was the only fancy stuff in the engine. Phil was so sick of his previous engines blowing up and having no spread of torque he just wanted something reliable and easy to drive. Piper BP300 rally cam, (later changed to a BP320), modest 11.4:1 CR, he already had nice alloy 1.625 ratio roller rockers, stock Payen head gasket and studs, stock lifter bore sizes. Pretty basic stuff really. Bigger lifters, more CR and valve lift/acceleration would have been nice if funds had allowed more high tech internals. The stock head studs were certainly rather limiting and apparently made out of something akin to chocolate but they just coped with 60 ft lbs (10 up on stock) and fortunately did the job.
Not too much point going into any depth on flow figures because your bench doesn't read the same as anyone else's but at 550 thou lift your 43mm inlet flowed 156 cfm compared to 170 cfm for the best port on my 45.7mm race head. I suspect that would equate to about 180 cfm on your own bench from the calibrations I've done. What I will say is your head flowed exceptionally well between 150 and 350 thou. More than I could ever achieve without sacrificing high lift flow but then it's getting that trade off right that's so critical.
On the second engine after a bit more flowbench time I came down to 45mm on the inlets to enable slightly larger exhausts to be fitted as I found that last 0.7mm on the inlet valves wasn't producing any more flow and was creating more clearance problems than it was worth. So after 30 odd years of building those awful things you've probably finally ended up at the same place I started
Good lad.Now then Dave
David Gollan, myself, Sally Dawes and my Son Simon were in the cafe in the car park at Donington, you were in there with Phil, we had overtaken your car, you came up and asked if we had put the 'new spec' race head on, we said no not yet, you were despondent. Now either you are lying or Dave Gollan, Sally and I were lying. Up to you, maybe you have removed it from your memory. Like you saying one of most successful B race engines ever in your first post!...,.one season and you didnt win the championship did you? No, we won by beating your car fair and square or can you not remember that either?
Re valve size, you got 150-160 bhp with big valves, how come we get more? Or are you going to say I am lying about bhp and Agra are lying too? You seem to have ignored the input that seems to put your B series and Pinto bhp claims to shame.
Take care Dave and don't lie, you get caught out.
As I said, you can knock me all you want but leave it for history to decide about MGB tuning.
I am not writing anymore on the subject and not rising to your ignorance. I shall leave you to dig your own hole. You have been spoiling for this for 20 years, grow up and move on, we have. It is no good dreaming of a few championships in the early 90s with no more since and resting on your laurels.
This forum, hopefully, is for folk to post and enjoy and ask questions and learn answers in a civilised manner, that is what I did asking about dellorto emulsion tubes.
It strikes me you are descending to schoolyard behaviour....the 'you are' syndrome.
Peter
David Gollan, myself, Sally Dawes and my Son Simon were in the cafe in the car park at Donington, you were in there with Phil, we had overtaken your car, you came up and asked if we had put the 'new spec' race head on, we said no not yet, you were despondent. Now either you are lying or Dave Gollan, Sally and I were lying. Up to you, maybe you have removed it from your memory. Like you saying one of most successful B race engines ever in your first post!...,.one season and you didnt win the championship did you? No, we won by beating your car fair and square or can you not remember that either?
Re valve size, you got 150-160 bhp with big valves, how come we get more? Or are you going to say I am lying about bhp and Agra are lying too? You seem to have ignored the input that seems to put your B series and Pinto bhp claims to shame.
Take care Dave and don't lie, you get caught out.
As I said, you can knock me all you want but leave it for history to decide about MGB tuning.
I am not writing anymore on the subject and not rising to your ignorance. I shall leave you to dig your own hole. You have been spoiling for this for 20 years, grow up and move on, we have. It is no good dreaming of a few championships in the early 90s with no more since and resting on your laurels.
This forum, hopefully, is for folk to post and enjoy and ask questions and learn answers in a civilised manner, that is what I did asking about dellorto emulsion tubes.
It strikes me you are descending to schoolyard behaviour....the 'you are' syndrome.
Peter
Hello Peter,
Back on topic.
In response to your question about emulsion tubes, I have in the past fettled the emulsion tubes on Dellortos to try to improve the fuel slope and fettled the progression drillings too, with mixed success, it was a long time ago now, probably 20-25 years and I cannot remember exactly what I did unfortunately, since I have been primarily working with injection since around 1994 I haven't really messed in depth with Dellortos or Webers barring a little help for friends with Caterhams and similar.
Dave
Back on topic.
In response to your question about emulsion tubes, I have in the past fettled the emulsion tubes on Dellortos to try to improve the fuel slope and fettled the progression drillings too, with mixed success, it was a long time ago now, probably 20-25 years and I cannot remember exactly what I did unfortunately, since I have been primarily working with injection since around 1994 I haven't really messed in depth with Dellortos or Webers barring a little help for friends with Caterhams and similar.
Dave
Hi Dave
Thank you for that.
I have played with emulsion tubes on Webers trying to drill but not much success. I tend to use the tuning book you can get from Weber which tells you which tubes are richer than others and where. I had heard there existed a similar chart for dellorto emulsion tubes have you ever come across this as I cannot track it down?
Peter
Thank you for that.
I have played with emulsion tubes on Webers trying to drill but not much success. I tend to use the tuning book you can get from Weber which tells you which tubes are richer than others and where. I had heard there existed a similar chart for dellorto emulsion tubes have you ever come across this as I cannot track it down?
Peter
PeterBurgess said:
Of interest Dave, as you say your engine DID NOT WIN ANY CHAMPIONSHIP which kind of implies you ‘talk the talk but don’t walk the walk’.
I'm not sure what sort of satisfaction it is you think you get from crowing that your car eventually won a championship that my guy only raced the first half of and then sold his car when he was offered a s**t load of money for it because it was crushing everything else out there. I believe it's quite easy to beat people who aren't actually competing against you any longer.Anyway, if you can put your ego to one side for a brief while I'm trying to make a sensible point here and get some sensible answers. I have no way of knowing if CES's engine dyno read high, low or correct but it's hard to cock up the calibration of an engine dyno and it removes all the variables like wheel slip that rollers are prone to. All I know is that with 141 independent engine dyno bhp Phil's car knocked 4 seconds a lap off his previous best time at Oulton Park with any of the three engine builders he'd gone to before me, qualified in pole by 2 seconds a lap faster than Hall and Hiley, as he also did at Silverstone, a renowned power circuit, and set new circuit records at most of the tracks he then went to before he sold it.
I also know that the Geoff Pyke engine was independently set up on Aldon Automotive's engine dyno and showed similar bhp to the Phil Conn engine on the independent CES engine dyno.
Finally I have the independent (non Clayton) rolling road figures for Geoff Pyke's old engine with your 43mm inlet valve race head and that had 110 bhp at the wheels. So maybe somewhere in the low 130s flywheel. Now there was certainly a bit more flow to come from larger valves like my own heads used and you say you do now but not 50 bhp's worth unless you've lost all touch with reality. Maybe 10 or 15.
So where the hell do figures like 180 or 190 bhp suddenly come from and if anyone, you or otherwise, could get even close to that how come 141 engine dyno bhp was enough to beat them?
As I've already tried to say, 180/190 bhp is a damn good figure for an average Pinto with wet sump, non filled head ports, 2 litre capacity and the average cams and other stuff that most people stick in them. Sure you can beat that with more capacity, apple port heads, dry sump, roller cams, ridiculous CR etc etc but that's not remotely comparable to the spec these MGBs had to be built to and usually to a tight budget. By the time you knock off the MGB power disadvantages like siamese ports, long stroke, small bore and much reduced head flow then 140/150 bhp looks eminently reasonable. Getting remotely close to the bhp of a crossflow, big bore, short stroke, bigger valved, higher flow, larger capacity engine does not look eminently reasonable!
So carry on thinking you're a tuning god who can defy the laws of physics but I'll stick to claiming the modest 141 bhp I saw on someone else's engine dyno and you can try and explain why your own engines had so much more claimed power but were 2 seconds a lap slower on the track and showed less power than mine on other people's rollers.
Hi
With out getting involved in a c**k measuring competition on here i would like to add my wee bit. I am regularly getting 150 BHP plus on C/F "B" series engines for Road Cars. With a bit more work on the cyl head a better manifold slightly improved cam and some more compression 180 BHP is now so 2002. And by the way its not my own dyno that these figures are coming off. I am about to put a 1622cc one on the dyno so we will see what that makes very soon. Pinto, well I would love to know the recipe for the big 200 plus engine, I look after a D/Sumped one 1998cc HT1E and every other mod and getting a very modest 203 BHP and JC the very capable driver/owner is not that far behind the BD powered Escort cars at KC race circuit doing low 60 second laps so it seems to be there or there about
Cameron Gilmour
figures are at the flywheel
With out getting involved in a c**k measuring competition on here i would like to add my wee bit. I am regularly getting 150 BHP plus on C/F "B" series engines for Road Cars. With a bit more work on the cyl head a better manifold slightly improved cam and some more compression 180 BHP is now so 2002. And by the way its not my own dyno that these figures are coming off. I am about to put a 1622cc one on the dyno so we will see what that makes very soon. Pinto, well I would love to know the recipe for the big 200 plus engine, I look after a D/Sumped one 1998cc HT1E and every other mod and getting a very modest 203 BHP and JC the very capable driver/owner is not that far behind the BD powered Escort cars at KC race circuit doing low 60 second laps so it seems to be there or there about
Cameron Gilmour
figures are at the flywheel
Nice to hear from you Cameron, I hope you are well?
I can remember later X/F engines with that snorty ex manifold you developed, to be honest I would have looked for about 12-15 more from the TVR with your cam and ex manifold on the small engine.
You are right about 2002 being so long ago in tuning terms. When Pete won that B championship even further back in 1992 we were running small inlet ports, 41.5 mm inlet valves and Pete wouldn't go over 10.6:1 CR. Pete won the same championship 1993 and 1994 before moving on to pastures new, he never went over 10.6:1 CR! Over the years we have played with valve sizing, port sizing, cam profiles,cam follower size etc etc and we have ended up running CR at 11.8:1. The most Cast Iron B headed race engine bhp we saw was with 13:1CR and Sunoco posh fuel. The ex manifold and system makes a big difference too.
I cannot shed any light on the Pinto of NMS, I only dynoed it, several times with different carb/choke combos. The engine was a 2.1, the big bhp Holbay one was a 2.4. I think quality of cam is vital on the big bhp Pintos. We saw 40 less at the wheels with the same spec engine but a non genuine 'Holbay' cam. The cam seems to be very very important wringing the geegees out. We improved the flow rate compared to the Holbay head but were surprised we only gained around 3 bhp!!!!!
Peter
I can remember later X/F engines with that snorty ex manifold you developed, to be honest I would have looked for about 12-15 more from the TVR with your cam and ex manifold on the small engine.
You are right about 2002 being so long ago in tuning terms. When Pete won that B championship even further back in 1992 we were running small inlet ports, 41.5 mm inlet valves and Pete wouldn't go over 10.6:1 CR. Pete won the same championship 1993 and 1994 before moving on to pastures new, he never went over 10.6:1 CR! Over the years we have played with valve sizing, port sizing, cam profiles,cam follower size etc etc and we have ended up running CR at 11.8:1. The most Cast Iron B headed race engine bhp we saw was with 13:1CR and Sunoco posh fuel. The ex manifold and system makes a big difference too.
I cannot shed any light on the Pinto of NMS, I only dynoed it, several times with different carb/choke combos. The engine was a 2.1, the big bhp Holbay one was a 2.4. I think quality of cam is vital on the big bhp Pintos. We saw 40 less at the wheels with the same spec engine but a non genuine 'Holbay' cam. The cam seems to be very very important wringing the geegees out. We improved the flow rate compared to the Holbay head but were surprised we only gained around 3 bhp!!!!!
Peter
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