Grief Update - Engine Rebuild
Discussion
good choice with that TTV FW helps my engine along with the other mods spins up like a mad idjeiot 
very un - RV8 like 
+1 from me Matthew, you seem to have all bases covered so I've got little to add other than I absolutely also love my TTV flywheel 
It was a massive surprise (literally) to me when I discovered years ago 4.0 litre cars unbelievably carry a standard Rover SD1 flywheel which weighs in at a stupidly heavy 32lbs, a 32lb flywheel may be ideal in a 1500kg saloon car designed to waft four passengers through town as smoothly as possible, but in a 1060kg 4.0 litre sports car 32lbs is nuts!
I was cautious not to go too light with my TTV flywheel as both people I spoke to separately who have the 15lb steel flywheel available off the shelf from V8 Tuner said they do need to raise the revs slightly more than normal when pulling away from a junction, I didn't want this so I had a bespoke all steel 8.5kg flywheel made which equates to 18.74lbs.
But that's still a whopping 13lbs plus lighter, and boy you can feel it
However!!!
The really amazing thing is since sorting out my various Canems issues the car now literally glides along right in the shunting zone all day long at what I would have previously considered a way way too lean14.7:1 AFR... and that's with a V8 development stealth cam which isn't a race cam but its more or less on the edge of being a track day cam with quite a bit of overlap.
'Ol Gasbag' is a pussy cat but give her a prod and she flys up the road like scolded cat, TBH I now think I could have gone for the 15lbs jobbie but you'll never know you've gone too light until you've gone too light
, so I played it safe at 18.74lbs which I choose to believe is the sweet spot compromise between perfect drivability and excellent throttle response.
Keeping to the feline theme here's a 13lb cat...
So this it what I removed from my flywheel mass
All it needs now is an ACT twin throttle plenum, if ya know what I'm saying mate
It was a massive surprise (literally) to me when I discovered years ago 4.0 litre cars unbelievably carry a standard Rover SD1 flywheel which weighs in at a stupidly heavy 32lbs, a 32lb flywheel may be ideal in a 1500kg saloon car designed to waft four passengers through town as smoothly as possible, but in a 1060kg 4.0 litre sports car 32lbs is nuts!
I was cautious not to go too light with my TTV flywheel as both people I spoke to separately who have the 15lb steel flywheel available off the shelf from V8 Tuner said they do need to raise the revs slightly more than normal when pulling away from a junction, I didn't want this so I had a bespoke all steel 8.5kg flywheel made which equates to 18.74lbs.
But that's still a whopping 13lbs plus lighter, and boy you can feel it
However!!!
The really amazing thing is since sorting out my various Canems issues the car now literally glides along right in the shunting zone all day long at what I would have previously considered a way way too lean14.7:1 AFR... and that's with a V8 development stealth cam which isn't a race cam but its more or less on the edge of being a track day cam with quite a bit of overlap.
'Ol Gasbag' is a pussy cat but give her a prod and she flys up the road like scolded cat, TBH I now think I could have gone for the 15lbs jobbie but you'll never know you've gone too light until you've gone too light
, so I played it safe at 18.74lbs which I choose to believe is the sweet spot compromise between perfect drivability and excellent throttle response.Keeping to the feline theme here's a 13lb cat...
So this it what I removed from my flywheel mass
All it needs now is an ACT twin throttle plenum, if ya know what I'm saying mate
+1 for TTV.
As part of my gearbox rebuild and clutch replacement TTV have made me a one-off steel flywheel with the crank trigger ring machined into the back ready for my GEMS install. About 6.5kg. All for a very reasonable £380, and it's a thing of beauty...not had it running yet, but it should spin up nicely and with the 5.0 rotating mass hopefully won't be an issue at low revs and pulling away. Got a nice new AP clutch on there as well so looking forward to a nice light(er) clutch pedal than the old Helix jobbie
As part of my gearbox rebuild and clutch replacement TTV have made me a one-off steel flywheel with the crank trigger ring machined into the back ready for my GEMS install. About 6.5kg. All for a very reasonable £380, and it's a thing of beauty...not had it running yet, but it should spin up nicely and with the 5.0 rotating mass hopefully won't be an issue at low revs and pulling away. Got a nice new AP clutch on there as well so looking forward to a nice light(er) clutch pedal than the old Helix jobbie
That's a thing of beauty Mike
Your choice of 6.5kg (14.33lbs) is a more or less 4.5lbs lighter than mine which is brave, but I think you'll be fine, a torquie 5.0 litre running the fully sequential GEMS system should be as smooth as silk.
I also had a Helix but now run a AP 5.0 litre clutch and the difference is night and day, do take the opportunity to check your release bearing carrier clearance though as this was an issue my Chimaera had from the day the car left Bristol Avenue in 1996, more on this here...
https://www.pistonheads.com/gassing/topic.asp?h=0&...
See my post dated Wednesday 29th Feb.
Your choice of 6.5kg (14.33lbs) is a more or less 4.5lbs lighter than mine which is brave, but I think you'll be fine, a torquie 5.0 litre running the fully sequential GEMS system should be as smooth as silk.
I also had a Helix but now run a AP 5.0 litre clutch and the difference is night and day, do take the opportunity to check your release bearing carrier clearance though as this was an issue my Chimaera had from the day the car left Bristol Avenue in 1996, more on this here...
https://www.pistonheads.com/gassing/topic.asp?h=0&...
See my post dated Wednesday 29th Feb.
So the reason I ask is obviously there will not be a reliable vacuum signal when you're running throttle bodies, and the MBE system like my Canems typically uses a MaP sensor. This is why I specifically directed the question at Matthew as I'm assuming this very element was discussed at length with Dom, I guess it's really Dom's answer I'm interested in as it will most accurately answer my question.
Quite obviously an engine speed signal is a given, but I know there are few ways to skin the throttle body cat so that's what I'm asking, for example I'm aware David Hampshire of Canems skinned this cat by developing a blend of TPS & MaP, a strategy he specifically offers for those running throttle bodies, so I was really just wondering if there will be a similar strategy with Mathews's MBE setup from Powers?
Now, what I'm about to say will probably be a little controversial but sometimes I feel we in the TVR world get a little bit too hung up on peak horsepower, the reality is you can make just as much peak torque/horsepower on a good carb as you can on injection assuming the choke sizes are not a restriction. If you think about it just for a second the Holly Grail should never be one number achieved at one point at peak RPM and load unless you really do drive everywhere at wide open throttle.
The Holly Grail is actually how the engine behaves from idle to peak RPM and load, its all that stuff in the middle we should be measuring success on and this is where injection should score every time over the carb!
More specifically it's all about that window you spend most time in, and this is where I'm going to make myself even more unpopular because the uncomfortable truth is we all choose to ignore is our cars spend 95% on the road, and driving on UK roads is going to include a lot of stop start lower RPM progress. Traffic jams, urban driving, periods at idle... sadly there's no getting away from it these conditions make up a huge amount of the time we actually spend driving our TVRs.
I don't like this sort of driving any more than any of us, but if you ignore this uncomfortable truth when you spec an engine because you mistakenly think you're going to Le Mans every day you'll soon understand what I'm talking about, don't get me wrong I'm not saying throttle bodies automatically mean poor drivability, far from it and here's how I know
I give you my good friend Alex's Porsche 912, a car I drive regularly.
You can read about it here...
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Actually that article is well our of date, at the time it was written the old four banger was long gone and it ran a 3.0 flat six from an 80's Carrera 911, but more recently that engine has been completely reimagined and fully balanced from the crank up including twin plug heads, a fully sequential MoTec engine management system... and of course those throttle bodies we're discussing here.
This was a £40k engine build so you better believe me when I say it works pretty well, of course that jewel of a flat six absolutely screams but it's the drivability that impresses me most. I know how they've achieved it with MoTec because I'm very close to the car and the project, but how will Powers get that same excellent drivability result with the MBE?
That's my question really, and it's a question to Matthew and Dom, or perhaps Dom's go to engine management guy
Matthew, I'm all ears
Quite obviously an engine speed signal is a given, but I know there are few ways to skin the throttle body cat so that's what I'm asking, for example I'm aware David Hampshire of Canems skinned this cat by developing a blend of TPS & MaP, a strategy he specifically offers for those running throttle bodies, so I was really just wondering if there will be a similar strategy with Mathews's MBE setup from Powers?
Now, what I'm about to say will probably be a little controversial but sometimes I feel we in the TVR world get a little bit too hung up on peak horsepower, the reality is you can make just as much peak torque/horsepower on a good carb as you can on injection assuming the choke sizes are not a restriction. If you think about it just for a second the Holly Grail should never be one number achieved at one point at peak RPM and load unless you really do drive everywhere at wide open throttle.
The Holly Grail is actually how the engine behaves from idle to peak RPM and load, its all that stuff in the middle we should be measuring success on and this is where injection should score every time over the carb!
More specifically it's all about that window you spend most time in, and this is where I'm going to make myself even more unpopular because the uncomfortable truth is we all choose to ignore is our cars spend 95% on the road, and driving on UK roads is going to include a lot of stop start lower RPM progress. Traffic jams, urban driving, periods at idle... sadly there's no getting away from it these conditions make up a huge amount of the time we actually spend driving our TVRs.
I don't like this sort of driving any more than any of us, but if you ignore this uncomfortable truth when you spec an engine because you mistakenly think you're going to Le Mans every day you'll soon understand what I'm talking about, don't get me wrong I'm not saying throttle bodies automatically mean poor drivability, far from it and here's how I know
I give you my good friend Alex's Porsche 912, a car I drive regularly.
You can read about it here...
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Actually that article is well our of date, at the time it was written the old four banger was long gone and it ran a 3.0 flat six from an 80's Carrera 911, but more recently that engine has been completely reimagined and fully balanced from the crank up including twin plug heads, a fully sequential MoTec engine management system... and of course those throttle bodies we're discussing here.
This was a £40k engine build so you better believe me when I say it works pretty well, of course that jewel of a flat six absolutely screams but it's the drivability that impresses me most. I know how they've achieved it with MoTec because I'm very close to the car and the project, but how will Powers get that same excellent drivability result with the MBE?
That's my question really, and it's a question to Matthew and Dom, or perhaps Dom's go to engine management guy
Matthew, I'm all ears
^^ your point of view isn't unpopular at all, in fact it's what every car should be .. ie a car that you can use in a variety of conditions .. good flat out and good not flat out.
For this reason it still absolutely amazes me that some mappers don't even take the car on the road after their mapping session, and the reason I often spend more time on the road than on the dyno when doing my own installs.
For this reason it still absolutely amazes me that some mappers don't even take the car on the road after their mapping session, and the reason I often spend more time on the road than on the dyno when doing my own installs.
spitfire4v8 said:
^^ your point of view isn't unpopular at all, in fact it's what every car should be .. ie a car that you can use in a variety of conditions .. good flat out and good not flat out.
For this reason it still absolutely amazes me that some mappers don't even take the car on the road after their mapping session, and the reason I often spend more time on the road than on the dyno when doing my own installs.
Exactly Jules, for example I'm loving what a new Japanese quality NTK MaP sensor has done for my drivability of late, as I'm sure you've learnt over the years good quality engine sensors can make sooo much difference! I also think what a lot of people completely fail to grasp is that better drivability can actually result in a faster car and I'm not just talking about road cars, on the track if the driver has better control and access to the available power he can apply it in a more accurate and measured way to achieve faster lap times.For this reason it still absolutely amazes me that some mappers don't even take the car on the road after their mapping session, and the reason I often spend more time on the road than on the dyno when doing my own installs.
I'm pleased we're on the same drivability page as sometimes I feel I'm the only man who feels passionately how fundamentally important it is, it can sometimes feel its all "I made 345hp or 373hp" ect ect on these pages but that's such a limited way to measure the success of any engine build and or engine management calibration work it can only be described as hopelessly one dimensional.
It was once explained to me that because fundamentally all internal combustion engines only really make their best power within a very narrow window the key objective for any engine designer (with the help of his engine management team) is to widen that window. Innovations such as variable valve timing, variable length inlet manifolds, and ever more sophisticated engine management systems have really helped designers in this endeavour in the last 20 years.
Obviously the designers and engine management team's work is not over, they must not only create that broadest possible window of power production but they must do it using as little chemical energy (fuel) as possible and also produce the lowest possible emissions in the process. These are fundamentals of engine efficiency, and efficiency (getting more for less) has always been the bedrock objective for any engineer, perpetual motion being the unobtainable Holly Grail.
Anyway Jules, sticking with drivability and broadening that window of usable power production how do you approach this challenge when you're setting up a car on throttle bodies
ChimpOnGas said:
Anyway Jules, sticking with drivability and broadening that window of usable power production how do you approach this challenge when you're setting up a car on throttle bodies
Trade secret I should imagine! As my joiner used to say to the apprentices when they asked how things were done, "it's taken a lifetime to learn everything I know, sod off and work it out yourself!"
phazed said:
ChimpOnGas said:
Anyway Jules, sticking with drivability and broadening that window of usable power production how do you approach this challenge when you're setting up a car on throttle bodies
Trade secret I should imagine! As my joiner used to say to the apprentices when they asked how things were done, "it's taken a lifetime to learn everything I know, sod off and work it out yourself!"
I know some specialists with niche knowledge are now not giving away their hard-won experience, and I'm inclined to agree with them nowadays .. it's especially irksome if you give your knowledge away to who you might consider to be a friend in the industry only to see them take your hard-won knowledge and use that to set up in competition with you, but it's worthless being angry about it. Some people do that. But that's also two-faced of me because obviously not everything I know has been self-taught .. people have given me the benefit of their experience either knowingly or unknowingly for which I'm very grateful of course. I do like to try and credit anyone who's given me valuable info though, it's only fair .. and indeed i have a signature on my emails to try to remind others to do the same.
But in answer to the question : I approach all my mapping the same way no matter what the configuration .. give the engine what it needs to make best power at all combinations of revs and load, the refine it back from there if you have areas of poor drivability.
Start from the point of best efficiency, then if you do have to make any changes you know you're only affecting the areas you need to and only by as much as you need to, and everything else is still at best efficiency.
You need a rolling road dyno, a seat of pants dyno, and experience to get you in the right ball park quickly. The first one can be bought for a price, the second and third ones are more tricky.
ChimpOnGas said:
Anyway Jules, sticking with drivability and broadening that window of usable power production how do you approach this challenge when you're setting up a car on throttle bodies
For the record what I meant by approach was the general setup you use 
, its just the general way you skin the throttle body cat and your comments on how others do it that I'm interested in.I'm aware you do not use a MaP sensor typically even on a standard plenum RV8 TVR so I guess I have my own answer, but I'd also be interested in your comments on David Hampshire's strategy of blending TPS & MaP for throttle body set ups?
On the other hand if you want to exchange trade secrets I've got a book of them on the Canems system
, trouble is the LPG chapter isn't all that valuable as no other begger has a Canems dual fuel system 
I've taught myself to become an expert in a market with just one customer, and that's myself
ChimpOnGas said:
For the record what I meant by approach was the general setup you use , its just the general way you skin the throttle body cat and your comments on how others do it that I'm interested in.
I'm aware you do not use a MaP sensor typically even on a standard plenum RV8 TVR so I guess I have my own answer, but I'd also be interested in your comments on David Hampshire's strategy of blending TPS & MaP for throttle body set ups?
I really don't see the point in the tps/map blend strategy, you're just making harder work for yourself with the mapping and anything that makes mapping harder work makes it more difficult to get a good map on the car., its just the general way you skin the throttle body cat and your comments on how others do it that I'm interested in.I'm aware you do not use a MaP sensor typically even on a standard plenum RV8 TVR so I guess I have my own answer, but I'd also be interested in your comments on David Hampshire's strategy of blending TPS & MaP for throttle body set ups?
This is the reason I like tps/revs based mapping, it's dead easy to get a very good map very quickly. It does however mean you need to be careful if you change anything relating to airflow because the ecu doesn't know about the airflow change. The good thing about the emerald though is you'd be hard pushed to find a mapper who hasn't used one before, so a local mapping agent should be relatively easy to find should you wish to make any changes to the spec of the engine etc. That can't be said of all systems out there.
Also I think it's important to be wary of anyone who claims they map 50 different systems .. I believe it's more important to know one or two systems very well and stick to them. I've tried mapping other ecus in the past and you're just on to a loser because you can't possibly know all the individual system shortcuts and tweaks that make mapping streamlined and efficient. If you don't know a system well you will end up with something sub standard. I only advertise mapping 4 systems, one I know very well, the others I know well enough. Anything else I turn away.
Map and AFM quite rightly have their advocates. And it's not for no reason that pretty much every manufacturer uses some form of airflow sensing in their cars .. but surely that's more about long term adaptability, ease of engine setting up for mass production, etc after all no major manufacturer is going to want to individually set up each car are they.
I've seen some beautiful tps based mapping and some poor AFM based mapping. The strategy employed is less important than the ego of the mapper too. Some one who's built a good ecu calibration has done a good job, irrespective of if they've done it largely by themselves as you have recently dave, or have been doing it for decades. If it's good it's good. If it's bad it's bad. Beware self-proclaimed gods.
I know my mapping level and it's small volume entry level stuff in reality compared to what happens in the major industry, but I think I do my entry level stuff well enough for the market.
In reality ..no two cars I see are in the same spec, so there's little point in standardising the maps .. I approach each car on a new basis. I have a startup map and ecu configuration, but that's all it is, something to get it up and running. From then on in it's a bespoke session tailored to that car.
However on a bespoke fit and bespoke map install I believe it makes more sense to be able to get the best map you can on the car in a reasonably short time. And by short time I mean under say 15 workshop hours including cold start and warmup phase time. I would imagine that I take typically 10-15 hours over mapping a car from start to finish including the dyno time, open road time, cold starts and accel enrich etc on a fresh emerald install .. That's a tiny tiny fraction of the time a manufacturer would spend on their calibrations of course , and you might reasonably argue that you are never finished with refining the map anyway, but why make that process even harder by using a mapping strategy that makes it so ?
anyway that rambled on and I'm not sure I even answered the question.
An excellent response, thanks.
What you're saying makes so much sense to me, I have spent many hours perfecting my Canems system and of course I have the added complication of needing to map the car twice over as I run two different fuel types.
I've had the Canems system for 7 years now, while I bought it with the ultimate intention of teaching myself mapping its only in the last 3 to 4 years that I really started in earnest on this journey. When comparing systems as I have aside from David Hamshire's dual fuel idea which completely changes the way you use the car as LPG is so ridiculously cheap, its the simplicity of the Canems software that's it's greatest advantage.
But even though the software is super intuitive it still takes time to learn and become an expert in, the way I learnt was to forensically unpick the calibrations I paid for and then through a process of trial and error slowly discovered what works and what doesn't... and most importantly spent time making sure I completely understood why! I found once I'd got over the initial fear of making changes and reminded myself I can always go back to my original calibration I very soon started to gain confidence in mapping the system.
Where it gets more complex is learning how various features can influence another feature, this teaches you a systematic approach to making and undoing changes one feature change at a time, this is essential to ensure you don't map yourself into a complex hole you can't find your way out of without starting again with your last calibration. These days the Canems software for me is so intuitive its like slipping on an old pair of shoes, I've looked at the Megasquirt Tunerstudio software which seems very good but would take me time to learn, actually I suspect I could get good results from it fairly quickly however to learn it deeply would be a life's work but this does kind of excite me for this very reason.
I've never looked at the Emerald software but I do hear good things about it, on the other hand I also have a friend who runs a MoTec but the software that comes with it looks like it could take me a lot longer to get my head around so I'll not be touching that. For now I'm happy to stick to being my own Canems mapping expert, its super simple and intuitive software has saved me a fortune in mapping work and has given me a new skill I am always happy to share if other's needing a little help with their Canems system.
I've achieved some fantastic improvements over the calibration I started out with and all this working at the significant disadvantage of not having a rolling road. My final point would be that starting with a good fundamental understanding of the spark ignition Otto cycle engine and fuels is essential, I would also never trust a mapper who didn't cut his teeth of carbs and distributors because these basic systems teach you better than anything else the fundamental principles of fuel and ignition timing tuning.
Oh, and as with everything in life always remember.... you never stop learning!
Anyway Matthew probably isn't the least bit interested in mapping his new engine so my apologies for the hijack, I was really just interested in how Powers approach the poor vacuum signal issue that comes hand in hand with throttle bodies
What you're saying makes so much sense to me, I have spent many hours perfecting my Canems system and of course I have the added complication of needing to map the car twice over as I run two different fuel types.
I've had the Canems system for 7 years now, while I bought it with the ultimate intention of teaching myself mapping its only in the last 3 to 4 years that I really started in earnest on this journey. When comparing systems as I have aside from David Hamshire's dual fuel idea which completely changes the way you use the car as LPG is so ridiculously cheap, its the simplicity of the Canems software that's it's greatest advantage.
But even though the software is super intuitive it still takes time to learn and become an expert in, the way I learnt was to forensically unpick the calibrations I paid for and then through a process of trial and error slowly discovered what works and what doesn't... and most importantly spent time making sure I completely understood why! I found once I'd got over the initial fear of making changes and reminded myself I can always go back to my original calibration I very soon started to gain confidence in mapping the system.
Where it gets more complex is learning how various features can influence another feature, this teaches you a systematic approach to making and undoing changes one feature change at a time, this is essential to ensure you don't map yourself into a complex hole you can't find your way out of without starting again with your last calibration. These days the Canems software for me is so intuitive its like slipping on an old pair of shoes, I've looked at the Megasquirt Tunerstudio software which seems very good but would take me time to learn, actually I suspect I could get good results from it fairly quickly however to learn it deeply would be a life's work but this does kind of excite me for this very reason.
I've never looked at the Emerald software but I do hear good things about it, on the other hand I also have a friend who runs a MoTec but the software that comes with it looks like it could take me a lot longer to get my head around so I'll not be touching that. For now I'm happy to stick to being my own Canems mapping expert, its super simple and intuitive software has saved me a fortune in mapping work and has given me a new skill I am always happy to share if other's needing a little help with their Canems system.
I've achieved some fantastic improvements over the calibration I started out with and all this working at the significant disadvantage of not having a rolling road. My final point would be that starting with a good fundamental understanding of the spark ignition Otto cycle engine and fuels is essential, I would also never trust a mapper who didn't cut his teeth of carbs and distributors because these basic systems teach you better than anything else the fundamental principles of fuel and ignition timing tuning.
Oh, and as with everything in life always remember.... you never stop learning!
Anyway Matthew probably isn't the least bit interested in mapping his new engine so my apologies for the hijack, I was really just interested in how Powers approach the poor vacuum signal issue that comes hand in hand with throttle bodies
Matthew Poxon said:
hoofa said:
Yes go for the ceramic on the pistons , I had mine done and some other stuff on the skirts
That's the one Nigel, gold on top and black on the skirts. How is yours coming along? The quality looks incredible from the pictures I have seen. 
ChimpOnGas said:
Anyway Matthew probably isn't the least bit interested in mapping his new engine so my apologies for the hijack, I was really just interested in how Powers approach the poor vacuum signal issue that comes hand in hand with throttle bodies
On the contrary, a good discussion and an interesting read.I did discuss this with Power a while back now and I cannot remember exactly what the answer was, I believe it will be mapped on throttle angle. I know it was satisfied with the answer at the time. When it gets to the mapping stage I will clarify.
Dom did say the mapping will be more tricky than with a plenum. Dom knows what I am after which is a car which drives impeccably around town and in traffic jams and will pull cleanly and smoothly on acceleration. He has said he is confident that he can achieve what I want. Sorry I don’t have the answers to hand, it will be a case of watch this space. As the build progresses I will continue to update on here.
Matthew Poxon said:
ChimpOnGas said:
Anyway Matthew probably isn't the least bit interested in mapping his new engine so my apologies for the hijack, I was really just interested in how Powers approach the poor vacuum signal issue that comes hand in hand with throttle bodies
On the contrary, a good discussion and an interesting read.I did discuss this with Power a while back now and I cannot remember exactly what the answer was, I believe it will be mapped on throttle angle. I know it was satisfied with the answer at the time. When it gets to the mapping stage I will clarify.
Dom did say the mapping will be more tricky than with a plenum. Dom knows what I am after which is a car which drives impeccably around town and in traffic jams and will pull cleanly and smoothly on acceleration. He has said he is confident that he can achieve what I want. Sorry I don’t have the answers to hand, it will be a case of watch this space. As the build progresses I will continue to update on here.
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