Why engine mods make no sense
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Joined: Oct 2000
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From: Bedford
Originally posted by ElTianti:
It is absurd to compare an engine intended for street use to a racing engine (F1 or otherwise). F1 engines have pneumatic valves, exotic alloys, barely idle, make exhaust you can smell anywhere at the track and require a team of mechanics to
start one. BMW got 1000+ hp from their F1 engine (1.5 liters) during the 80s F1 turbo era. However, it used fuel that cost several hundred dollars a gallon.
It is absurd to compare an engine intended for street use to a racing engine (F1 or otherwise). F1 engines have pneumatic valves, exotic alloys, barely idle, make exhaust you can smell anywhere at the track and require a team of mechanics to
start one. BMW got 1000+ hp from their F1 engine (1.5 liters) during the 80s F1 turbo era. However, it used fuel that cost several hundred dollars a gallon.
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From: You wish
I believe I posted on this once before, but there is a lot of power left in this engine without even changing the bottom end. I will not comment on cost, since that is a personal issue for most, but I will say that the modifications required will not incur a significant reliability, durability or economy penalty.
1. Intake/Exhaust mods on Honda DOHC VTEC engines have never had the same effect they do on less developed engines (historically large displacement V8s). That these mods have minimal effect on the F20C should be no surprise. That they have any effect is pleasing.
2. The true arbiters of power in a DOHC VTEC engine are the cams. It took awhile for developers to bring out billet cams for the B-series engines (Integra GS-R, Civic Si, etc.) but when they did, power gains were enormous. On the order of 12-15 hp for a totally streetable (and emissions passing) set of cams. Bigger cams, with some idle compromise net on the order of 20 hp or more. Toda cams are on my list when they come out.
3. Cylinder head design. Stock Honda heads are good, but they can be improved. The F20C head has no handwork done on it. That means the valve seating surface is probably overly thick (necessary to simplify the installation process), the valve profiles/stems are not optimum, etc. Another 10 hp minimum should be possible here (and a lot more if history holds true).
4. Engine control. This is probably the biggest issue facing us right now. We've got an OBDII ECU which does some funky things. Doesn't mean it will kill power, but we either have to understand how it works to maximize gains, or we have to replace it.
5. Intake manifold/Individual Throttle Bodies. The stock piece is a compromise, even Honda engineers have admitted that in their SAE article. Its designed for quick throttle response, but in return plenum volume has been reduced. A larger plenum may net some surprising gains. ITBs almost certainly will.
I could go on and talk about the output of 2.0 liter touring car engines, which face more restrictions than we do and often must last the better part of a race season. Or about how artificial the dropoff in power above 8300 rpm on the S2K is. However, let me just bring up a historical precedent.
Back in 1994-1995, when the Integra GS-R was wowing autowriters and selling like hotcakes, many of those supposedly "in the know" were saying that the engine was tapped out, that if you really wanted to have a fast Integra through modification, you should buy the RS/LS and modify that. After all, the VTEC system was too complex and it was going to be hard to get more hp out of the engine. Looking back now, I think its safe to call those folks shortsighted at a minimum. The B18C engine can pick up another 40-60 hp, normally aspirated, and still remain very durable. Yes, that's correct, there are 7-8 year old B18C engines that produce as much wheel hp as our S2000s do and they do it on pump gas and are driven daily (the race versions produce even more). I owned one, and still have the dyno sheet on my desk. It had 10 lbs-ft of torque on my S2K (on the same dyno) until 6000 rpm, matched it from 6000-7800 rpm and was only a couple lbs-ft down past that. And it ran on regular pump gas and passed emissions quite well, even retained the factory cat and a full exhaust. Oh, and it got much better gas mileage in a car that was only 100 lbs lighter.
Sorry for the long post, but I feel strongly about and have a little experience in this area. If I had the resources to produce cams and develop an aftermarket engine management system, I would. But for now, I'm willing to wait.
UL
1. Intake/Exhaust mods on Honda DOHC VTEC engines have never had the same effect they do on less developed engines (historically large displacement V8s). That these mods have minimal effect on the F20C should be no surprise. That they have any effect is pleasing.
2. The true arbiters of power in a DOHC VTEC engine are the cams. It took awhile for developers to bring out billet cams for the B-series engines (Integra GS-R, Civic Si, etc.) but when they did, power gains were enormous. On the order of 12-15 hp for a totally streetable (and emissions passing) set of cams. Bigger cams, with some idle compromise net on the order of 20 hp or more. Toda cams are on my list when they come out.
3. Cylinder head design. Stock Honda heads are good, but they can be improved. The F20C head has no handwork done on it. That means the valve seating surface is probably overly thick (necessary to simplify the installation process), the valve profiles/stems are not optimum, etc. Another 10 hp minimum should be possible here (and a lot more if history holds true).
4. Engine control. This is probably the biggest issue facing us right now. We've got an OBDII ECU which does some funky things. Doesn't mean it will kill power, but we either have to understand how it works to maximize gains, or we have to replace it.
5. Intake manifold/Individual Throttle Bodies. The stock piece is a compromise, even Honda engineers have admitted that in their SAE article. Its designed for quick throttle response, but in return plenum volume has been reduced. A larger plenum may net some surprising gains. ITBs almost certainly will.
I could go on and talk about the output of 2.0 liter touring car engines, which face more restrictions than we do and often must last the better part of a race season. Or about how artificial the dropoff in power above 8300 rpm on the S2K is. However, let me just bring up a historical precedent.
Back in 1994-1995, when the Integra GS-R was wowing autowriters and selling like hotcakes, many of those supposedly "in the know" were saying that the engine was tapped out, that if you really wanted to have a fast Integra through modification, you should buy the RS/LS and modify that. After all, the VTEC system was too complex and it was going to be hard to get more hp out of the engine. Looking back now, I think its safe to call those folks shortsighted at a minimum. The B18C engine can pick up another 40-60 hp, normally aspirated, and still remain very durable. Yes, that's correct, there are 7-8 year old B18C engines that produce as much wheel hp as our S2000s do and they do it on pump gas and are driven daily (the race versions produce even more). I owned one, and still have the dyno sheet on my desk. It had 10 lbs-ft of torque on my S2K (on the same dyno) until 6000 rpm, matched it from 6000-7800 rpm and was only a couple lbs-ft down past that. And it ran on regular pump gas and passed emissions quite well, even retained the factory cat and a full exhaust. Oh, and it got much better gas mileage in a car that was only 100 lbs lighter.
Sorry for the long post, but I feel strongly about and have a little experience in this area. If I had the resources to produce cams and develop an aftermarket engine management system, I would. But for now, I'm willing to wait.
UL
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I have got to agree with UL, and time will tell. It was big news when the B16A broke production engine records with 100hp/L. Honda themselves topped that same engine with the B16B at 115.6hp/L, and others were able to do more through the years.
The S2000 has only been around a little while, so it will take time. It seems most of the people in the US just desire the car to pet it, while the rest of the world has more enthusiasm to smack the Vtec around the circuit, so they will probably be the ones developing the cool stuff.
The S2000 has only been around a little while, so it will take time. It seems most of the people in the US just desire the car to pet it, while the rest of the world has more enthusiasm to smack the Vtec around the circuit, so they will probably be the ones developing the cool stuff.
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SilverFog-
Unlike you, I have already contributed many, many times to this board on the effectiveness of simple bolt on parts and modifications. However, to each their own. Do a search. I don't see why my opinion has to be justified, especially to someone like you, who did not "add anything substantial" to this thread- wholly which did not "add anything substantial" to this entire board except for being erroneous in nature.
Go get your supercharger. I hope it stays on your car for a long, long time and that you derive much enjoyment out of it.
I ask you this question again- who do you think actually designed the motor in the S2000?
[Edited by GTRPower on 05-24-2001 at 10:20 AM]
Unlike you, I have already contributed many, many times to this board on the effectiveness of simple bolt on parts and modifications. However, to each their own. Do a search. I don't see why my opinion has to be justified, especially to someone like you, who did not "add anything substantial" to this thread- wholly which did not "add anything substantial" to this entire board except for being erroneous in nature.
Go get your supercharger. I hope it stays on your car for a long, long time and that you derive much enjoyment out of it.
I ask you this question again- who do you think actually designed the motor in the S2000?
[Edited by GTRPower on 05-24-2001 at 10:20 AM]
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Joined: Apr 2001
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From: La Habra
I'm also with UL on this. I also want a reliable engine when I'm done. This thread is certainly flame-baiting but it could refresh us on mods that were done, or will be done.
Look at the throttle body. Several posters claim overall improvement adding a, around $150, part. Is the original poster going to tell me that is "violating" the fine work Honda engineers put into our machines? I have to stay away from most mods while I race in stock class. That doesn't mean I'm not making plans for mods down the road.
And if a replacement air filter gets me 2 HP. Well, that's legal and worth more than 0.1 seconds on an Auto-X course. I'm slightly unhappy that Honda engineers did not see fit to give that to me up front (along with a lighter weight - non-powered top & windows, single exhaust, etc.) but i also didn't want to pay $50K for the car.
I'm willing to sacrifice gas mileage, acoustic noise, and a limited amount of $$ in the pursuit of performance. Maybe you are not. And the Honda engineers obviously were not.
Look at the throttle body. Several posters claim overall improvement adding a, around $150, part. Is the original poster going to tell me that is "violating" the fine work Honda engineers put into our machines? I have to stay away from most mods while I race in stock class. That doesn't mean I'm not making plans for mods down the road.
And if a replacement air filter gets me 2 HP. Well, that's legal and worth more than 0.1 seconds on an Auto-X course. I'm slightly unhappy that Honda engineers did not see fit to give that to me up front (along with a lighter weight - non-powered top & windows, single exhaust, etc.) but i also didn't want to pay $50K for the car.
I'm willing to sacrifice gas mileage, acoustic noise, and a limited amount of $$ in the pursuit of performance. Maybe you are not. And the Honda engineers obviously were not.
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From: El Segundo
ultimate lurker your post might be long, but it gives a lot of useful information. I also am waiting for the Toda cams to come out. Now I know that everyone wants horse power gains, but if you have not heard what an exhaust system sounds like on a S2000 you are missing out. On Saturday I followed 1Y2KS2k with the Neuspeed exhaust and S2k FAN with the HKS exhaust. Their is nothing like the sound of a high compression engine with exhaust. Also by changing the exhaust you do save weight too.
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[QUOTE]I am confident there is more power in there. And I am going after it. If you assume a baseline of 240, which I did NOT establish with a dyno pulled (regrettably), the car is
close to what someone here said I may reach a glass ceiling of 20 hp without FI. We plan to shatter it
close to what someone here said I may reach a glass ceiling of 20 hp without FI. We plan to shatter it
