Amuse-ing day at the dyno
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From: San Diego
Spent a couple hours on the dyno today with Jeff Schaefer at Import Builders (IB) in Fullerton, CA.
As a stock-class autocrosser I'm limited in "legal" power-adding modifications: air filter and cat-back exhaust being the only real ones.
Did a bone-stock baseline a little while ago on their dyno - peak hp was 193 at the wheels:
Since then I've installed the 8lb. Amuse exhaust system, primarily for the lighter weight and racier sound, which it definitely delivered on. I was skeptical that I would see the ~9hp gain Amuse claimed. Turns out my skepticism was unfounded in this instance, as tonight the car was roughly 8hp stronger at peak and higher across the board.
Here are plots of 3 different air filter configurations with the new exhaust. The blue line was with a custom-made CAI-like intake Jeff put on to try out. I can't use a CAI but the gains shown there are similar to what others have reported with the AEM/Injen CAIs. Note the big bump in torque around 6000rpm. The JR filter netted me about 1hp over stock on my car. I'll be sticking with Honda filters...
I also brought 5 gallons of 100 octane gas to try out. The tank was nearly empty for the first part of testing, so the 5 gallons brought the effective octane up to about 97-98 I'd guess. Now, most will say that the ECU needs time to learn about this fuel and adapt to it and whatnot, but for me that wasn't really necessary. I don't have the accessibility to 100 octane or the desire to be paying that much for gas to really give the ECU a chance to adapt to it. If I were ever going to use 100 octane it would be for a little kick at the dragstip, track, or autocross, where there wouldn't be time to learn. I was only interested in the immediate effects of high octane, which (putting aside the outlying first pull that was 4hp higher due to the 5 gallons of ice-cold gas) were nil:
I have in the past, but will not in the future be using 100 octane.
I wanted to compare the bone-stock results with today's results, but it wouldn't have been a straight-up comparison since the environmental conditions (which the dyno software measures) were different. So here's the "uncorrected" outputs:
On a more general note, I noticed that the first pull in each configuration (we did 3 in each, and used the average one for the graphs) was always the highest, usually by about 2hp. This, no doubt due to the engine and its parts heating up. My best runs at the dragstrip have all been after letting the car cool for 40 minutes or more. The point being, keeping things cool (by whatever means you choose) is definitely worthwhile. I'll probably be investing in a low-temp Mugen thermostat.
Many thanks to Jeff at Import Builders for an expert job. If you're in the San Diego/Orange County/LA areas, definitely consider his shop - he's got a ton of experience building and tuning Hondas, including dozens of S2Ks. They're hosting a "dyno day" on Feb. 24th which is an excellent and inexpensive opportunity to get a baseline.
Cheers!
As a stock-class autocrosser I'm limited in "legal" power-adding modifications: air filter and cat-back exhaust being the only real ones.
Did a bone-stock baseline a little while ago on their dyno - peak hp was 193 at the wheels:
Since then I've installed the 8lb. Amuse exhaust system, primarily for the lighter weight and racier sound, which it definitely delivered on. I was skeptical that I would see the ~9hp gain Amuse claimed. Turns out my skepticism was unfounded in this instance, as tonight the car was roughly 8hp stronger at peak and higher across the board.
Here are plots of 3 different air filter configurations with the new exhaust. The blue line was with a custom-made CAI-like intake Jeff put on to try out. I can't use a CAI but the gains shown there are similar to what others have reported with the AEM/Injen CAIs. Note the big bump in torque around 6000rpm. The JR filter netted me about 1hp over stock on my car. I'll be sticking with Honda filters...
I also brought 5 gallons of 100 octane gas to try out. The tank was nearly empty for the first part of testing, so the 5 gallons brought the effective octane up to about 97-98 I'd guess. Now, most will say that the ECU needs time to learn about this fuel and adapt to it and whatnot, but for me that wasn't really necessary. I don't have the accessibility to 100 octane or the desire to be paying that much for gas to really give the ECU a chance to adapt to it. If I were ever going to use 100 octane it would be for a little kick at the dragstip, track, or autocross, where there wouldn't be time to learn. I was only interested in the immediate effects of high octane, which (putting aside the outlying first pull that was 4hp higher due to the 5 gallons of ice-cold gas) were nil:
I have in the past, but will not in the future be using 100 octane.
I wanted to compare the bone-stock results with today's results, but it wouldn't have been a straight-up comparison since the environmental conditions (which the dyno software measures) were different. So here's the "uncorrected" outputs:
On a more general note, I noticed that the first pull in each configuration (we did 3 in each, and used the average one for the graphs) was always the highest, usually by about 2hp. This, no doubt due to the engine and its parts heating up. My best runs at the dragstrip have all been after letting the car cool for 40 minutes or more. The point being, keeping things cool (by whatever means you choose) is definitely worthwhile. I'll probably be investing in a low-temp Mugen thermostat.
Many thanks to Jeff at Import Builders for an expert job. If you're in the San Diego/Orange County/LA areas, definitely consider his shop - he's got a ton of experience building and tuning Hondas, including dozens of S2Ks. They're hosting a "dyno day" on Feb. 24th which is an excellent and inexpensive opportunity to get a baseline.
Cheers!
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On the race gas thing...I tested Ultra 94 versus unleaded race gas on a 1988 4 cyl M3 with about 232 crank HP. Under ideal conditions it barely helped, and you had to do a few runs to get some averaging to increase result credibility.
BUT.
If the car was heat soaked..idling or going below about 20-25 MPH for 5-10 minutes there was a big difference. About 8-10 HP. And across a wide RPM range. The race gas did not add power, but it kept power or avoided fading better than the street gas. The car has a CAI stock, from BMW Motorsports.
Since you mentioned autocross, this could be a concern as you stage for 5-10 minutes before a run and need to have fluids up to temp. If you get a chance and are still curious I'd try some heat soaked dyno runs with different fuels.
The M3 cools itself off enough to regain HP after about 30-60 seconds of above 25 MPH operation. So if I was heat soaked I'd be back at full power by the END of my autocross run.... If i'm in a long line I like to close the hood at the last moment, keeping it cracked for the last few minutes. Heater on. Thermotec header blanket (not wrap) really helped cut underhood temps since the temp of the headers at idle is about 5-600 degrees F.
Stan
BUT.
If the car was heat soaked..idling or going below about 20-25 MPH for 5-10 minutes there was a big difference. About 8-10 HP. And across a wide RPM range. The race gas did not add power, but it kept power or avoided fading better than the street gas. The car has a CAI stock, from BMW Motorsports.
Since you mentioned autocross, this could be a concern as you stage for 5-10 minutes before a run and need to have fluids up to temp. If you get a chance and are still curious I'd try some heat soaked dyno runs with different fuels.
The M3 cools itself off enough to regain HP after about 30-60 seconds of above 25 MPH operation. So if I was heat soaked I'd be back at full power by the END of my autocross run.... If i'm in a long line I like to close the hood at the last moment, keeping it cracked for the last few minutes. Heater on. Thermotec header blanket (not wrap) really helped cut underhood temps since the temp of the headers at idle is about 5-600 degrees F.
Stan
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From: Phoenix
Great post. Good info. It looks like you noticed the same thing I did on the dyno and that was the first run (actually the first 2 in my case) were about 2-4 hp above my usual dyno. I also noticed that in the first two runs my air/fuel was about a point higher than usual for the first run...half a point higher than usual for the second run...and then normal for the third run. And when I say normal I mean all runs there after stayed at where my third dyno run was. Does anyone know the reason for this??? I understand the hp thing because of the car getting hot but why would my air/fuel change like that.
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From: You wish
Jason,
Couple of comments:
If the JR was worth 1 hp and doesn't require replacement ever (only cleaning) why wouldn't you continue to use it? Also, gauze/screen filters tend to flow much better than paper with even mild amounts of contamination (i.e. flow a dirty JR vs. a dirty stock).
Second, when you compare actual numbers (vs. SAE corrected) the higher test results indicate better conditions. For example, to correct your original run (193 hp SAE vs. 195 actual) the correction factor must have been about 0.99 or 0.98. However, to correct the recent runs (212 to 201 SAE), the correction factor had to be about 0.95 - indicating cooler temps and/or higher barometric pressure. Usually this can be seen on the dyno sheets, although with the new dynojet software it sometimes doesn't.
In the end, the correction factor is there to make everything as equal as possible. If someone posts a dyno sheet with "SAE" numbers on the side, then its o.k. to compare. But if it says actual hp, the numbers are pretty worthless unless they were all done on the same day - and even then you can't compare to other cars. The "high" stock numbers I've seen have all been using the correction factor, which is pretty standard. Since most people seem to hover right around 200 hp stock, the 193's or the 208's may just be the outliers in a distribution.
Also, on the variance between runs. On other cars I've usually seen high initial runs followed by lower 2nd runs. However, on the S2000, on dynojets, I've seen the opposite. Last year, at R&D, socal28's car proceeded to make more hp for each succeeding run up to run 3 or 4. the car was reading full temp on teh dash, so we were surprsied. The dyno operator stated that he had seen this phenomena before on OBDII cars. Hisguess was that the ECU wants more temp for better emissions. Higher operating temps are better for that, but I don't know if that's the real reason. Either way, I always like to throw out the first run or two since variances do occur.
UL
Couple of comments:
If the JR was worth 1 hp and doesn't require replacement ever (only cleaning) why wouldn't you continue to use it? Also, gauze/screen filters tend to flow much better than paper with even mild amounts of contamination (i.e. flow a dirty JR vs. a dirty stock).
Second, when you compare actual numbers (vs. SAE corrected) the higher test results indicate better conditions. For example, to correct your original run (193 hp SAE vs. 195 actual) the correction factor must have been about 0.99 or 0.98. However, to correct the recent runs (212 to 201 SAE), the correction factor had to be about 0.95 - indicating cooler temps and/or higher barometric pressure. Usually this can be seen on the dyno sheets, although with the new dynojet software it sometimes doesn't.
In the end, the correction factor is there to make everything as equal as possible. If someone posts a dyno sheet with "SAE" numbers on the side, then its o.k. to compare. But if it says actual hp, the numbers are pretty worthless unless they were all done on the same day - and even then you can't compare to other cars. The "high" stock numbers I've seen have all been using the correction factor, which is pretty standard. Since most people seem to hover right around 200 hp stock, the 193's or the 208's may just be the outliers in a distribution.
Also, on the variance between runs. On other cars I've usually seen high initial runs followed by lower 2nd runs. However, on the S2000, on dynojets, I've seen the opposite. Last year, at R&D, socal28's car proceeded to make more hp for each succeeding run up to run 3 or 4. the car was reading full temp on teh dash, so we were surprsied. The dyno operator stated that he had seen this phenomena before on OBDII cars. Hisguess was that the ECU wants more temp for better emissions. Higher operating temps are better for that, but I don't know if that's the real reason. Either way, I always like to throw out the first run or two since variances do occur.
UL
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From: San Diego
Thanks for the insight Mr. UL! Turns out I had the C.F. thing backwards. So if I get it right a C.F. of 1.0 is "normal conditions" - conditions better than this receive a CF<1, but worse conditions would receive a CF>1. I think. ? 
The stock filter and JR filter I ran both had a few thousand miles on them. I also ran a just-out-of-the-bag stock filter. The graphs were stepping on each other all over the place, with only a very slight edge to the JR. I used to run a conical K&N in my CRX and was pretty happy with it, but later when I was researching what to do with my 944, I read a big report by a well-respected engineer on the Rennlist that had done a study with various aftermarket filters vs. the factory Porsche filter, and found the stock piece filtered better. Since then I've been a bit wary of the reusables. Your thoughts? I'd be willing to sacrifice a small performance gain if the stock filter keeps more junk out.
My runs showed a very consistent pattern of power loss with consecutive runs. We did 3 runs in each config and every run lost 1 or 2 hp over the previous. This was even after running the car on the dyno at low speed for a couple minutes before the first pull. Just a guess, but it could be that between runs the fuel and intake got cooled off quite a bit (since it was in the 50s), but not enough to cool off the cat or emissions gear outside of their ideal range.
The dyno time was fun - I only wish I had more things like a VAFC to play with for modification. Makes me want to get another car just to tinker with....
The stock filter and JR filter I ran both had a few thousand miles on them. I also ran a just-out-of-the-bag stock filter. The graphs were stepping on each other all over the place, with only a very slight edge to the JR. I used to run a conical K&N in my CRX and was pretty happy with it, but later when I was researching what to do with my 944, I read a big report by a well-respected engineer on the Rennlist that had done a study with various aftermarket filters vs. the factory Porsche filter, and found the stock piece filtered better. Since then I've been a bit wary of the reusables. Your thoughts? I'd be willing to sacrifice a small performance gain if the stock filter keeps more junk out.
My runs showed a very consistent pattern of power loss with consecutive runs. We did 3 runs in each config and every run lost 1 or 2 hp over the previous. This was even after running the car on the dyno at low speed for a couple minutes before the first pull. Just a guess, but it could be that between runs the fuel and intake got cooled off quite a bit (since it was in the 50s), but not enough to cool off the cat or emissions gear outside of their ideal range.
The dyno time was fun - I only wish I had more things like a VAFC to play with for modification. Makes me want to get another car just to tinker with....
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From: You wish
Yes Jason, your interpretation of correction factors is correct. The whole intent is to standardize the numbers according to accepted practice. Under very good conditions, the car will make more hp than standard, so the factor must be less then 1.
As for filters, I've heard some of same concerns as you have. AFAIK, there haven't been any reported wear issues, anecdotally or under a controlled study. Considering the wide use of K&N type filters in motorsports with some very expensive equipment, I'm not overly worried. Also, if I'm not mistaken (and Mingster could probably provide info here) the JR filters have undergone some pretty strict testing in Europe through TUV and/or MIRA.
I'm not sure why the car reads lower or higher after each run. My normal experience (before socal28's car) was that you'd lose hp from the 1st to the 2nd or 3rd run but then it would pretty much stabilize.
UL
As for filters, I've heard some of same concerns as you have. AFAIK, there haven't been any reported wear issues, anecdotally or under a controlled study. Considering the wide use of K&N type filters in motorsports with some very expensive equipment, I'm not overly worried. Also, if I'm not mistaken (and Mingster could probably provide info here) the JR filters have undergone some pretty strict testing in Europe through TUV and/or MIRA.
I'm not sure why the car reads lower or higher after each run. My normal experience (before socal28's car) was that you'd lose hp from the 1st to the 2nd or 3rd run but then it would pretty much stabilize.
UL
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From: socal
very interesting report Jason. so will you be at the practice this Sat. at the Q? i'll be there with my 116.2hp silver Miata.
but it's scary what this 116.2hp can do combined with 2175lbs.
of course i'll there Sun. as well..drop by Sat. if you aren't doing anything..i'll give you a couple of rides (spins).
but it's scary what this 116.2hp can do combined with 2175lbs.
of course i'll there Sun. as well..drop by Sat. if you aren't doing anything..i'll give you a couple of rides (spins).
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From: San Diego
Hey Ken,
I sent in my sheet for the practice, but haven't been notified yet if I'll get to run. I'll be at the Q on Saturday and Sunday in either case - it's only about 3 miles from me.
Well, it's even scarier what it can do in the hands of a good driver! At the last couple events I've been to, you've been quicker in that Miata than the whole field of (the new) BS! 
I sure hope Jason gets his car all sorted soon so he can continue to "represent" the S2000 in So Cal!
I sent in my sheet for the practice, but haven't been notified yet if I'll get to run. I'll be at the Q on Saturday and Sunday in either case - it's only about 3 miles from me.
but it's scary what this 116.2hp can do combined with 2175lbs.
At the last couple events I've been to, you've been quicker in that Miata than the whole field of (the new) BS! I sure hope Jason gets his car all sorted soon so he can continue to "represent" the S2000 in So Cal!
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From: Utah & Bay Area
How do you like the sound of the amuse single tip? I've heard it can be too loud for a daily driver. I'm thinking of replacing my stock exhaust with the amuse single / all titanium for the weight savings. Any sound clips outside the garage?
-MSM
-MSM