Ideas for engine mods ?
Discussion
What would people do in my position ...... ?
My Griff (a 1999 500) will be going in for a service at Austec in 1K miles (40K 'ish service) - now the weather is getting better that shouldn't take too long
The car has been sorted previously by MA (plus straight through exhaust and smooth bore induction pipe) but Paul Austin has said when they did it the timing had to be held back to prevent detonation as the injectors on my car were running at the safe maximum.
Do I go for new injectors, AFM, trumpets and a remap accordingly in the hope that it allows the ignition to be suitably advanced further and thereby giving me some more oomph at higher revs ......
OR do I do all this and get a triple plenum as well to save the cost of a remap later as I am likely to get it at some stage anyway ?
If I can get an increase without going for the triple plenum I may be satisfied (he says, trying to convince himself !)
I have known Paul for some time and am more than happy with his work - he has not tried the half way option before so can't given any idea as to what power I will end up with. He says in theory it should work but it is a bit of an unknown whereas with the triple plenum he has done plenty and has a much better idea of where I will end up with power wise .......
Any views appreciated from anyone who has gone down this route ....... oh, and for info cam is std and will remain so at the moment.
My Griff (a 1999 500) will be going in for a service at Austec in 1K miles (40K 'ish service) - now the weather is getting better that shouldn't take too long
The car has been sorted previously by MA (plus straight through exhaust and smooth bore induction pipe) but Paul Austin has said when they did it the timing had to be held back to prevent detonation as the injectors on my car were running at the safe maximum.
Do I go for new injectors, AFM, trumpets and a remap accordingly in the hope that it allows the ignition to be suitably advanced further and thereby giving me some more oomph at higher revs ......
OR do I do all this and get a triple plenum as well to save the cost of a remap later as I am likely to get it at some stage anyway ?
If I can get an increase without going for the triple plenum I may be satisfied (he says, trying to convince himself !)
I have known Paul for some time and am more than happy with his work - he has not tried the half way option before so can't given any idea as to what power I will end up with. He says in theory it should work but it is a bit of an unknown whereas with the triple plenum he has done plenty and has a much better idea of where I will end up with power wise .......
Any views appreciated from anyone who has gone down this route ....... oh, and for info cam is std and will remain so at the moment.
To be honest,thesedays,the mods you suggest are a very inefficient way to modify the Griff in terms of £/bhp.I'd start with a different cam first(there are better cams with better low down manners and better top end performance),then work from the inside outwards,ie inlet manifold,trumpets,plenum.A lot will also come down to just how original you want to keep the engine bay also.If you can afford it,your far better off junking the Lucas ecu and AFM for example(either type of afm is a good restriction to bhp).I also found a good set of exhaust manifolds makes a lot of difference as well.I'd suggest a chat with V8 Developments as your first move to be honest,what they don't know about the RV8,isn't worth knowing as they say
>> Edited by mongoose on Sunday 30th April 14:49
>> Edited by mongoose on Sunday 30th April 14:49
I agree with Mongoose. Bugger all point going for the AFM and injectors alone; you'll need to change the plenum to get the benefit. Standard injectors are on the whole fine for your engine (cleaning them might help a bit). If you want to significantly change the fuelling and airflow then you'll want a different cam and trumpets, and then you're looking at a fairly typical set of modifications, i.e. shouldn't have too much trouble getting it set-up well. If you haven't already then I would put some dosh to one side for suspension and brakes. Power wise, I would expect around 10bhp without the cam change, or around 30bhp with a new cam, e.g. H404. Works out approx £100-per-BHP.
Will follow this thread with interest and it would be useful if you update us on what you decide and what the result is. I posted a similar question last year, prompted by the same advice about my 98 Griff (engine is pinking, probably because of the injectors) although I was not able to detect the pinking. After a lot of consideration and discussion I went for Trumpets, Bosch injectors, Cam, Chip and Map. The work started in February and I wish I could say that it was a success and still hope it will be, eventually. So far however the car has spent most of it’s time not running well or broken, at the moment it is very broken.
It would be a great help if those of you who have had these sort of mods and are happy would come forward and say what the results are, because you seem to be a strangely quiet bunch.
Given the chance to wind the clock back I would not choose this route. Rather than using a “tuner’ I would leave alone or go to one of the specialist engine builders and get an entire engine built to a spec and with a warranty.
I understand incidentally that the twin Plenum gives a snappier throttle response where the trumpets actually allow a bit more power to be extracted when married to a hotter cam and the appropriate mapping. I think that once you have the trumpets in place and everything setup it is fairly straightforward to fit the twin Plenum.
It would be a great help if those of you who have had these sort of mods and are happy would come forward and say what the results are, because you seem to be a strangely quiet bunch.
Given the chance to wind the clock back I would not choose this route. Rather than using a “tuner’ I would leave alone or go to one of the specialist engine builders and get an entire engine built to a spec and with a warranty.
I understand incidentally that the twin Plenum gives a snappier throttle response where the trumpets actually allow a bit more power to be extracted when married to a hotter cam and the appropriate mapping. I think that once you have the trumpets in place and everything setup it is fairly straightforward to fit the twin Plenum.
steve-v8s said:Really? That's more or less what I have (cam, twin throttle & plenum, no pre-cats, Tornado chip and a few other bits - magnacores etc... 300bhp / 325 lbs ft runs a treat, drives well, goes like stink.
It would be a great help if those of you who have had these sort of mods and are happy would come forward and say what the results are, because you seem to be a strangely quiet bunch.
Rich... >> Edited by richb on Sunday 30th April 19:17
steve-v8s said:
OK, that is good, where are the rest of you ?
No results as yet sorry Steve, I'll give you an update in 2 weeks time.
But I've done a complete engine rebuild with a H404 cam, pre cats removed, ACT induction kit, ceramic coated manifolds (internal and external) and the usual small bits like plug leads, coil, hoses etc. It will be set up at V8Dev this week.
TBH I was very happy with the engine as standard, it was only because I was refreshing it anyway that I decided to change a few things.
If I wasn't doing a re-fresh I'd probably have left it standard and spent the money on the chassis, petrol and track days!
Dave
>> Edited by David H on Sunday 30th April 19:42
Marlon said:Spot on in my experience.The thing is it really all depends what you are looking for in the modifications.The standard plenum is good for up to 320 bhp(with the 72mm throttle),but the twin or triple will give much better throttle response for example.The std injectors are fine for more than 310bhp so far i've found,and some say up to 330bhp,its just down to increasing fuel pressure to get more from them.
I agree with Mongoose. Bugger all point going for the AFM and injectors alone; you'll need to change the plenum to get the benefit. Standard injectors are on the whole fine for your engine (cleaning them might help a bit).
there are so many different ways you can go depending on what you want.I cant subscribe to the belief that it costs £100/ 1 bhp either,not any more it doesnt.One of the mods i've done cost £20 odd and gained 8bhp and 8ftlb at peak figures,and more at some points in the dyno curve,and it gained all through the rev range at WOT!!Even averaging all the mods i've done,its nowhere near the £100/1bhp mark.Whichever way you choose to go,its certainly great fun discovering what does what
PS.the power figures i've quoted are on Track car sollutions dyno.
>> Edited by Mongoose on Sunday 30th April 21:24
Rich...I've got a bit of info now from running lots of cars on the dyno..
std injectors are not a problem up to around 330bhp, maybe slightly more. I had a car making 322bhp on std injectors and it was too rich on it's crushed regulator.
the std 5am airflow meter costs bhp at every point over 150bhp .. ie it's a limitation on every TVR engine. Up to 150bhp it costs no bhp at all, but neither is there any increase in midrange that is often talked about from keeping the AFM .. back to back testing shows it only ever loses bhp never gains it.
std plenum and even an enlarged throttle body is costing about 15bhp on any engine delivering a genuine 300+bhp as is. I did some measurements and found the twin throttle system with 50mm butterflies has less total butterfly area than the enlarged std alloy plenums but has more on twin 55mm throttles.. in which case the upped airflow would add about 7% but you really need to get rid of the airflow meter to see proper gains, with cheap aftermarket systems that's a real tuning avenue. with the lucas yuo're stuck with either limiting the airflow at over 150bhp's worth or going for larger bosch style metering, obviously for both cases you can sell your old stuff to offset some of the costs.
throttle figures :
1*72mm area= 3600sqmm
2*50mm area=3120sqmm
2*55mm area= 3872sqmm
I also ran some tests on a 5 litre griff that was turning about 265bhp as std .. the results are quite surprising, like adding trumpets only gained 2bhp, but a smooth elbow to the plenum added 6bhp, and 8bhp on a 300bhp car!
My preferred route would be in order:
smoothed elbow, heat-wrap protected inner wing pipe (not a restriction to airflow but does pick up heat)
trumpet base isolator
blended trumpet base
bigger plenum throttle plate
camshaft
mappable ecu with no airflow meter
V8D heads
JE alloy triple plenum
but just doing some serious air heat management i gained the best part of 15bhp on an otherwise std 5 litre car for less than 400 pounds! after that though it gets expensive
std injectors are not a problem up to around 330bhp, maybe slightly more. I had a car making 322bhp on std injectors and it was too rich on it's crushed regulator.
the std 5am airflow meter costs bhp at every point over 150bhp .. ie it's a limitation on every TVR engine. Up to 150bhp it costs no bhp at all, but neither is there any increase in midrange that is often talked about from keeping the AFM .. back to back testing shows it only ever loses bhp never gains it.
std plenum and even an enlarged throttle body is costing about 15bhp on any engine delivering a genuine 300+bhp as is. I did some measurements and found the twin throttle system with 50mm butterflies has less total butterfly area than the enlarged std alloy plenums but has more on twin 55mm throttles.. in which case the upped airflow would add about 7% but you really need to get rid of the airflow meter to see proper gains, with cheap aftermarket systems that's a real tuning avenue. with the lucas yuo're stuck with either limiting the airflow at over 150bhp's worth or going for larger bosch style metering, obviously for both cases you can sell your old stuff to offset some of the costs.
throttle figures :
1*72mm area= 3600sqmm
2*50mm area=3120sqmm
2*55mm area= 3872sqmm
I also ran some tests on a 5 litre griff that was turning about 265bhp as std .. the results are quite surprising, like adding trumpets only gained 2bhp, but a smooth elbow to the plenum added 6bhp, and 8bhp on a 300bhp car!
My preferred route would be in order:
smoothed elbow, heat-wrap protected inner wing pipe (not a restriction to airflow but does pick up heat)
trumpet base isolator
blended trumpet base
bigger plenum throttle plate
camshaft
mappable ecu with no airflow meter
V8D heads
JE alloy triple plenum
but just doing some serious air heat management i gained the best part of 15bhp on an otherwise std 5 litre car for less than 400 pounds! after that though it gets expensive
steve-v8s said:No one seems to know
What cam do you have fitted Richb ?
But seriously it was suplied by TVR Power back in 2000 and back then they simply called it their "Upgraded cam for teh Groff 500" 
seriously! It requires solid lifters and adjustable steel pushrods. Since then I have been given different stories by Dom about what it actually is and the most likely stroy is that it's a predecesor to their Taraka cam without a name! It's running very well since Paul at Austec did the valve clearances a month ago, that's the problem with solid-lifters the tappets seem to go off rather quickly. R...Gassing Station | Griffith | Top of Page | What's New | My Stuff