Puzzled by the whp gain after ITB

[greenberet]

Yeah, the horsepower and torque curves are almost identical with both sets of maps. It’s nice to see that the fuel and ignition maps custom-programmed for your car get you a few more horsepower than the maps programmed for NA1/2-R GT’s car. That’s why it’s good to get these things custom-programmed (by someone who knows what they’re doing).

Looking at the air / fuel ratios, NA1/2-R GT’s fuel map is a bit richer than yours at full throttle. Maybe that’s why his nets you a few less horsepower.

Also, the little downwards spike in torque is at about 5130 rpm. That’s also the rpm at which the car is running the richest - the rpm at which the engine is inhaling the least amount of air for the fuel being injected. Since you have a freely programmable engine management computer maybe that’s just where the VTEC changeover point was set, as you already stated. When the chip for my engine management computer was programmed, the dyno showed a clear dip in the torque curve at the VTEC changeover point which I can’t feel while driving, either.

In any case, your horsepower graphs before and after the ITBs look good. With the ITBs and fuel and ignition maps optimized for your engine you now have more power at almost every rpm and a significant increase up top. Plus sharper throttle response and the ITBs look cool.

One thing popped into my mind why you might have gotten a lower percentage gain than NA1/2-R GT. NA1/2-R GT’s dyno graph clearly states “Torque Flywheel lbft” on the left so it shows crank horsepower not wheel horsepower on the right. However, NA1/2-R GT mentions WHP in his post. Maybe the before run shows WHP and the after run had some percentage added to estimate crank hp. If you try to remove the driveline losses from the after run to convert it back into wheel hp, the gains look a lot more similar to yours. But that’s just a wild guess that could be totally wrong.

Edit: by the way, did you happen to keep the engine compartment hatch closed during any of the dyno runs to see how horsepower is impacted when the ITBs inhale warm air from the engine compartment instead of cool air from outside?

 

[FD3SNSX]

This is exactly what I expected. For there to be little to no difference. That is still a healthy gain, although I do wonder what closing it off with a filter will do. Have you dyno'ed that at all? I am assuming all these runs are unfiltered?

All the runs were done w/o filters. I ordered them online but I have yet to receive them.

And did you still have the restrictive exhaust on?

Yes

Yeah, the horsepower and torque curves are almost identical with both sets of maps. It’s nice to see that the fuel and ignition maps custom-programmed for your car get you a few more horsepower than the maps programmed for NA1/2-R GT’s car. That’s why it’s good to get these things custom-programmed (by someone who knows what they’re doing).

Looking at the air / fuel ratios, NA1/2-R GT’s fuel map is a bit richer than yours at full throttle. Maybe that’s why his nets you a few less horsepower.

Also, the little downwards spike in torque is at about 5130 rpm. That’s also the rpm at which the car is running the richest - the rpm at which the engine is inhaling the least amount of air for the fuel being injected. Since you have a freely programmable engine management computer maybe that’s just where the VTEC changeover point was set, as you already stated. When the chip for my engine management computer was programmed, the dyno showed a clear dip in the torque curve at the VTEC changeover point which I can’t feel while driving, either.

In any case, your horsepower graphs before and after the ITBs look good. With the ITBs and fuel and ignition maps optimized for your engine you now have more power at almost every rpm and a significant increase up top. Plus sharper throttle response and the ITBs look cool.

One thing popped into my mind why you might have gotten a lower percentage gain than NA1/2-R GT. NA1/2-R GT’s dyno graph clearly states “Torque Flywheel lbft” on the left so it shows crank horsepower not wheel horsepower on the right. However, NA1/2-R GT mentions WHP in his post. Maybe the before run shows WHP and the after run had some percentage added to estimate crank hp. If you try to remove the driveline losses from the after run to convert it back into wheel hp, the gains look a lot more similar to yours. But that’s just a wild guess that could be totally wrong.

Edit: by the way, did you happen to keep the engine compartment hatch closed during any of the dyno runs to see how horsepower is impacted when the ITBs inhale warm air from the engine compartment instead of cool air from outside?

You are correct. Only reason why I was able to gain alittle more peak power was cuz my map is leaner compare to Dan's.

We did not test it w/the hatch closed although I wish I did. Maybe 'jde' can try this out when he goes to the dyno after his ITB installation.

Tae

 

[Caustic]

Yes

I know you like your exhaust, but if you are going to go through the process of extensive testing, you should try to understand that parts of the whole system that can be improved. An exhaust can make the difference of 0 - 10+ hp (perhaps a lot of the whp you suspect is missing) or even negative performance. After you know what is possible, you can make a better informed decision as to whether the sacrifice is worth it to you or not.

 

[FD3SNSX]

I know you like your exhaust, but if you are going to go through the process of extensive testing, you should try to understand that parts of the whole system that can be improved. An exhaust can make the difference of 0 - 10+ hp (perhaps a lot of the whp you suspect is missing) or even negative performance. After you know what is possible, you can make a better informed decision as to whether the sacrifice is worth it to you or not.

I know what you are saying and I am researching for a new one. What I really want to do is to gather local NSX owners with different/popular exhaust system and test them on the same day/same car/same dyno.

Tae

 

[whrdnsx]

whrdnsx I assume the better hp result was with lighter wheels?

Yes, OEM 34GTR wheels over Simmons 3 piece. we were amazed.

anyway back on topic, NA engines are very critical on being a complete package, everything must be matched, extra air in must be complemented by effective camshaft timings & exhaust scavenging out. If one thing is not matched then sometimes you'll go backwards.

I still say FI is the best value for $ spent as much as i like the ITB sound & throttle response.

 

[Ponyboy]

I thought the mid range plunge was due to passover to VTEC ? no?? While driving, I don't feel any power loss in that range.

I kinda doubt you'd sense anything that quick. However, imho, it is still a concern as it doesn't follow the normal hp and tq curve and you're missing some power. But I don't think anyone would fault you for looking or not looking into it.

All the runs were done w/o filters. I ordered them online but I have yet to receive them.

 

[ENT]

Throttle response goes a long way towards making a car feel faster and way more fun to drive but if you're looking for guaranteed throttle response then i would start with higher gearing.

Cheers,
Ian

 

[TURBO2GO]

Throttle response goes a long way towards making a car feel faster and way more fun to drive

True, but so does 100 HP... LOL

 

[Brooklynzson]

Were you ever able to squeeze anymore Hp out??

 

[ScienceofSpeed]

One thing popped into my mind why you might have gotten a lower percentage gain than NA1/2-R GT. NA1/2-R GT’s dyno graph clearly states “Torque Flywheel lbft” on the left so it shows crank horsepower not wheel horsepower on the right. However, NA1/2-R GT mentions WHP in his post. Maybe the before run shows WHP and the after run had some percentage added to estimate crank hp. If you try to remove the driveline losses from the after run to convert it back into wheel hp, the gains look a lot more similar to yours. But that’s just a wild guess that could be totally wrong.

This is a mistake in the Dynapack software. New versions are corrected and show "Axle" instead of flywheel on the print outs.

-- Chris

 

[L_RAO]

I'm going to think out loud (for better or for worse) on this thread:

1. I don't see an AF chart.

2. In my fuel injector project, I was told by someone (who I can't remember - I've spoken to so many people at this point) that fuel injector X has a "straight" (less than 15 degree arc) spray pattern, which is better for a certain intake system design, while fuel injector Y has more of a spread (30 degree+ arc) spray pattern, which is better for a different intake system design. Perhaps this is a path you can research further and pursue.

3. In my conversations with John at HyTech, he felt that there was still an additional 20+ wHP to be found in exhaust systems over the current aftermarket offerings. From an engineering standpoint, both OEM and aftermarket, a lot of compromises had to be made in order for the headers, cats, and exhaust to (1) fit, and (2) be "streetable" (i.e., noise).

To this point, you have gone "all out" (so to speak) on the induction side (save for a dedicated hatch scoop to feed the ITBs), while you are still have a (relative) bottleneck in your exhaust system.

I think tinkering with points 2 and 3, and double checking on #1 will result in a happier OP.

 

[NA1/2-R GT]

I'm going to think out loud (for better or for worse) on this thread:

1. I don't see an AF chart.

2. In my fuel injector project, I was told by someone (who I can't remember - I've spoken to so many people at this point) that fuel injector X has a "straight" (less than 15 degree arc) spray pattern, which is better for a certain intake system design, while fuel injector Y has more of a spread (30 degree+ arc) spray pattern, which is better for a different intake system design. Perhaps this is a path you can research further and pursue.

3. In my conversations with John at HyTech, he felt that there was still an additional 20+ wHP to be found in exhaust systems over the current aftermarket offerings. From an engineering standpoint, both OEM and aftermarket, a lot of compromises had to be made in order for the headers, cats, and exhaust to (1) fit, and (2) be "streetable" (i.e., noise).

To this point, you have gone "all out" (so to speak) on the induction side (save for a dedicated hatch scoop to feed the ITBs), while you are still have a (relative) bottleneck in your exhaust system.

I think tinkering with points 2 and 3, and double checking on #1 will result in a happier OP.

I agree with you on the bottleneck possiblility.
I believe there's a hurdle in my headers set up. I am looking to do some experiementing with other type of headers. I am leaning toward Fujitsubo right now, but might go with other type with proven performance.

 

[TURBO2GO]

I agree with you on the bottleneck possiblility.
I believe there's a hurdle in my headers set up. I am looking to do some experiementing with other type of headers. I am leaning toward Fujitsubo right now, but might go with other type with proven performance.

I might sell my GT-One F1 headers if you are interested. I actually think I need more of a forced induction header, and I think the GT-one may be the perfect setup for you. I believe it will be a better header for you than the Fujitsubo, as this is the only header on the market that is true equal length tubing on all 6 pipes. The Fuitsubo is only equal on one bank (3), and then equal on the other bank (the other 3). All 6 are NOT equal. I looked at both and the build quality on the GT-one is the best I saw of any header. I paid over $3400 for the unit when I bought it, and it is in perfect condition with around 5K miles on it. It also has provisions for an aftermarket 02 gauge, I paid another few hundred to get that installed. I don't know what else you can get out there that would be better on an ITB setup.

 

[StmpoRaceProducts]

since everyone is so technical here... technically.. the only way your getting this gain for 5k is if you can install this set up on your own, you own an injector company, also an aftermarket ecu company, and you happened to be an expert car tuner with your own dyno.

this is a 7.5-8.5k set up = currently measured at 20-41 hp

with an addition exspense of an airbox possibly a hatch as well...

dont confuse calculating with bashing..

 

[Stephen@NCAutoUSA]

I might sell my GT-One F1 headers if you are interested. I actually think I need more of a forced induction header, and I think the GT-one may be the perfect setup for you. I believe it will be a better header for you than the Fujitsubo, as this is the only header on the market that is true equal length tubing on all 6 pipes. The Fuitsubo is only equal on one bank (3), and then equal on the other bank (the other 3). All 6 are NOT equal. I looked at both and the build quality on the GT-one is the best I saw of any header. I paid over $3400 for the unit when I bought it, and it is in perfect condition with around 5K miles on it. It also has provisions for an aftermarket 02 gauge, I paid another few hundred to get that installed. I don't know what else you can get out there that would be better on an ITB setup.

Not to derail this thread but doesn't Cody make an equal length aftermarket header as well? Even though it may be for his turbo kits I'm sure since he makes them to order he can fab up something.

 

[TURBO2GO]

Not to derail this thread but doesn't Cody make an equal length aftermarket header as well? Even though it may be for his turbo kits I'm sure since he makes them to order he can fab up something.

I don't think his are equal on all 6 either. I'm not 100% but if you know differently for sure let me know. His FI header is what I am considering if I sell mine but I am not sure I want to make this swap or if it is worth the hassle. I am very happy with the GT-1's but I think I'd gain a few with a slightly larger pipe with a supercharger. The fujitsubo uses a fairly large pipe and on Vance's old dyno pulls he lost a bit of torque and HP except on the very top end where he gained a couple. I think piping shape and diameter are very important in a MATCH to the motor. Cody's design is a forced induction design unless he is now making something I am unaware of.

 

[sparky]

this is a 7.5-8.5k set up ...

how did you get to those total cost figures ??

 

[NSX UNITED]

I might sell my GT-One F1 headers if you are interested. I actually think I need more of a forced induction header, and I think the GT-one may be the perfect setup for you. I believe it will be a better header for you than the Fujitsubo, as this is the only header on the market that is true equal length tubing on all 6 pipes. The Fuitsubo is only equal on one bank (3), and then equal on the other bank (the other 3). All 6 are NOT equal. I looked at both and the build quality on the GT-one is the best I saw of any header. I paid over $3400 for the unit when I bought it, and it is in perfect condition with around 5K miles on it. It also has provisions for an aftermarket 02 gauge, I paid another few hundred to get that installed. I don't know what else you can get out there that would be better on an ITB setup.

Dave, other than being all equal length, you forgot to mention the GT-One Header is also equal in diameter (50mm) to the GT-One F1 Exhaust. Hence in terms of throttle response, your current setup can't be beat. I believe you're also running test pipes, right? I'm running test pipes (also 50mm) with the same setup as yours and it's awesome. I understand there might be a difference since I'm running NA and yours with FI.

I would keep the GT-One if I were you just in case since you can't get them anymore due to their bankruptcy. Moreover, what's $3400 gonna do for you when you ain't short of cash, right? :wink: In fact, I know I'm right, you owe me a drink. :biggrin:

 

[E-Nough Logic]

Ok guys, here are the results. These runs were done on the dynojet. We first ran with my map, then ran again after loading Dan's map w/o making any changes. We did this multiple times and the results were pretty same.

Blue is with Dan's map tuned by Tony/UMS
Red is my map tuned by Ray/PFSupercars
Here are the data
Dynojet Research Inc.
Run Name: C:\DynoRuns\HONDA\NSX\Tae\RunFile_016.drf
Run Title:
Run Notes:
Run Date: 9/29/2011 7:45:22 PM
RunFile_016.drf: 88.72 °F 29.47 in-Hg Humidity: 21 % SAE: 1.01 Average Gear Ratio: 53.74
s RPM x1000 hp ft-lbs Air/Fuel
0.39 2.75 11.64 22.17 14.27
1.36 3.00 100.35 175.68 13.01
2.31 3.25 108.53 175.39 11.62
3.21 3.50 123.60 185.47 12.02
4.12 3.75 129.85 181.86 12.33
5.00 4.00 146.20 191.97 13.02
5.88 4.25 151.64 187.39 12.25
6.73 4.50 172.41 201.23 12.48
7.56 4.75 182.18 201.44 12.78
8.39 5.00 191.04 200.67 12.30
9.24 5.25 207.82 207.90 11.77
10.02 5.50 223.09 213.04 12.46
10.84 5.75 224.81 205.34 12.28
11.66 6.00 235.16 205.85 12.21
12.47 6.25 252.51 212.19 12.73
13.25 6.50 267.19 215.89 12.77
14.06 6.75 267.42 208.08 12.61
14.92 7.00 265.16 198.95 12.47
15.81 7.25 270.06 195.64 12.53
16.69 7.50 278.78 195.22 12.66
17.58 7.75 284.54 192.83 12.79
--------- --------- --------- --------- ---------
MAX: 17.58 7.75 284.54 215.89 14.27
MIN: 0.39 2.75 11.64 22.17 11.62
--------------------------------------------------------------------------------
Dynojet Research Inc.
Run Name: C:\DynoRuns\HONDA\NSX\Tae\RunFile_017.drf
Run Title:
Run Notes:
Run Date: 9/29/2011 7:58:26 PM
RunFile_017.drf: 88.64 °F 29.47 in-Hg Humidity: 20 % SAE: 1.01 Average Gear Ratio: 53.78
s RPM x1000 hp ft-lbs Air/Fuel
0.75 2.75 91.13 174.05 12.68
1.69 3.00 102.12 178.78 13.70
2.60 3.25 112.24 181.39 12.89
3.49 3.50 124.69 187.11 13.09
4.40 3.75 129.53 181.41 13.15
5.28 4.00 146.46 192.30 13.56
6.16 4.25 151.83 187.63 13.02
7.00 4.50 171.87 200.60 13.28
7.83 4.75 182.89 202.23 13.42
8.65 5.00 192.80 202.52 12.85
9.49 5.25 207.58 207.66 12.48
10.27 5.50 225.61 215.44 13.43
11.07 5.75 227.58 207.87 13.10
11.89 6.00 236.64 207.15 12.86
12.69 6.25 253.50 213.03 13.08
13.47 6.50 268.15 216.67 13.49
14.28 6.75 271.03 210.89 13.46
15.13 7.00 267.62 200.80 13.24
16.00 7.25 270.10 195.67 13.17
16.88 7.50 280.97 196.75 13.17
17.78 7.75 286.22 193.97 13.27
18.69 8.00 289.73 190.21 13.28
--------- --------- --------- --------- ---------
MAX: 18.69 8.00 289.73 216.67 13.70
MIN: 0.75 2.75 91.13 174.05 12.48

Multiple runs were done but the results were same and the highest WHP gained using my map was 296whp, which is 29whp difference compared to my base.

I was surprised/glad to see how the results from two different maps were almost identical because that proves there was nothing wrong with the tune itself. Overall, I am very happy with the result. The throttle response/sound/more tourqe makes the drive 1000x better/fun.

I'm surprised the difference in A/F didn't make a larger difference. It appears that Dan's tune has more fuel which either means his engine consumes more air or his tuner made an unnecessarily rich map. Of course the ignition values aren't there so that could make up the difference.

What is VTEC set for? You can see the engine getting much richer at the 5250rpm area than the rest of the map in that area a full point richer on both maps. Moving the VTEC engagement point might clean that up the torque drop.

 

[Ko-nsx]

I don't think his are equal on all 6 either. I'm not 100% but if you know differently for sure let me know. His FI header is what I am considering if I sell mine but I am not sure I want to make this swap or if it is worth the hassle. I am very happy with the GT-1's but I think I'd gain a few with a slightly larger pipe with a supercharger. The fujitsubo uses a fairly large pipe and on Vance's old dyno pulls he lost a bit of torque and HP except on the very top end where he gained a couple. I think piping shape and diameter are very important in a MATCH to the motor. Cody's design is a forced induction design unless he is now making something I am unaware of.

http://www.nsxprime.com/forum/showthread.php?t=131643&highlight=lovefab+headers&page=4
Check out post #84

 

[L_RAO]

http://www.nsxprime.com/forum/showthread.php?t=131643&highlight=lovefab+headers&page=4
Check out post #84

Great link. This is a good piece of evidence that well-designed headers will make power OVER other generic/off the shelf/poorly designed aftermarket headers. Quick math: the 15.5 wHP is a 3.25% increase over the previous best.

 

[StmpoRaceProducts]

how did you get to those total cost figures ??

5k = gets it to your door... if not more considering tax should or will be added no matter what now

1100 - aem / or 700-800 for fic and harness… everyone forgets the harness isn’t cheap

600-800 injectors

150.00 fule pump – 150.00 - installed

500-800 = install

100 - tow or rental

tune - 800-1500 - depends on how good or exclusive your tuner is... if you’re getting the tune for less.. get a new tuner


Then ur left with an reliable car now unreliable. You need a filter at some point or your gonna detonate and airbox… which may have the filter in it.. but there’s no room above itb’s. I know ponyboy doesnt drive his car.. i'll probably need to defend how he drives his car more than the national average..,. but he doesnt drive his car.

You need a few other parts to fix the minimal horsepower gain problem.. but I’m keeping my mouth shut there. Do not call, email or pm me on how to cure this... I learned my lesson fixing other manu's problems on this forum

my quantified $.02

 

[TURBO2GO]

Great link. This is a good piece of evidence that well-designed headers will make power OVER other generic/off the shelf/poorly designed aftermarket headers. Quick math: the 15.5 wHP is a 3.25% increase over the previous best.

A single dyno test is far from a scientific test, for all I know the SC could have cooled more and produced slightly better numbers. I am not saying Cody's header ISN'T better than the one it replaced in an FI car, but I'd really take any numers with a grain of salt. I cannot believe how quickly people on this forum are convinced with one chart and one run. Anyway, please let the header issue die. We are derailing the thread now.

 

[L_RAO]

No, a single test isn't, but any evidence is better than the NOTHING we were dealing with before.

As to the single test itself, it was done on the same day with the same dyno, and it was done by a vendor/tester who has a good reputation; I wouldn't suspect any sort of funny business with the #s.

One of the biggest problems the NSX community has is that parts are expensive, so is repeated dyno testing. As a result, there isn't a lot of dyno data out there. We are smart enough here to look at a set of results and make our own conclusions. Would I like more tests? Of course. I'd love a MEGA shoot-out for basic bolt-ons. Header A vs. B vs. C vs. D, etc. But there isn't enough money in it, for the dyno facility or for the vendor.

 

[TURBO2GO]

it was done on the same day with the same dyno, .

I have dyno runs done the same day on the same dyno that vary by 13 HP without ANY mods.