My New Dyno Results

[Quicksilver]

I went to my local tuner shop today (Modacar) to get a baseline dyno run done now that I have the Hondata reflash and replaced my 2 1/4" crush bent mid-pipe for a Comptech 2 1/2" mandrel bent full exhaust. My previous results (translated from a Dyno Dynamics dyno to DynoJet) were 153.2 hp and 127.4 tq with AEM CAI, DC header, crush bent mid-pipe and Hondata intake gasket manifold. It should also be noted that I have 17" rim/tire combo that are 1 lb lighter than stock, but throws the rotating mass out further which can lower the numbers marginally. I also have 2-piece brake rotors that are 1 lb lighter than stock also. So overall, I'd say the numbers should compare close to a person running stock wheels/tire/brakes. And my numbers do approximate out to others that have similar mods.

That all being said, I was figuring I'd put down around 155-160 hp and 130-135 tq. I figured that the Hondata reflash might give me a little gain on the top end, and the exhaust could lose me a little low end torque, but help in the upper end. After the first baseline run, I knew something was wrong. The two follow-up runs confirmed that I was WAY below where I should be power-wise. They were very consistent though, so I don't think it's a fluke. Here's a breakdown of my runs:

Run 1:
Max Power: 145.06
Max Torque: 125.46

Run 2:
Max Power: 145.74
Max Torque: 125.61

Run 3:
4th gear pull (vs. the others done in 3rd) showed a lower results, so they stuck with 3rd. This was just to see if it would make more power in 3rd or 4th.

Run 4:
Max Power: 145.41
Max Torque: 125.68


All of the numbers were done on that latest DynoJet with the latest software and are SAE corrected. The air/fuel ratio stayed between 14:1 and 12:1 (centering around 13:1 for the most part) on all runs after 3k rpm.

Given all that, I am very dissappointed! I know that the exhaust could be partly to blame, but others have shown gains with the Comptech exhaust. I think more likely it's the ECU reflash that's losing me the majority of the power. I knew before buying it to only expect about a 7hp gain at best, and no gain at the worst, but losing 7.5 hp and 1.7 tq by adding a reflash and ECU is just ridiculous!!!

I'll be e-mailing Doug at Hondata to get his opinion on this, but it may be a while since he's over in the U.K. right now. Something just isn't making sense here, but I can't figure out what. I'm just not a happy camper right now. I'll post the dyno page when I get home from work tonight.

[myeverlovinsir]

Hmmm, sorry to say but that's about what I would expect. Last year we did the exhaust tests on the dyno. Stock flows fairly well. Velocity in the exhaust goes down as you increase the diameter and so does tq. I don't recall anyone testing out a 2.5" mandrel bent pipe, but I know that the 2.5" crush I tried last year showed about the same losses, especially in the tq resonating area of the curve. (~4500rpms). Again, 2.25" crush bent is the largest you want to go NA. Even Joey's 2" mandrel bent pipe showed no gains compared to the 2.25" crush. Which are about equivalent seeing that the crush bends inside neck down to near 2" anyway.

I think you might have been mislead if someone told you that you would get 7hp from the flash. Last year I could not show any gains from 3 EP's stock/modded and then Hondata. Doug was puzzled then and probably still is. I seriously doubt that any dyno results one way or the other are attributable to Hondata.

How is the driving experience?

[eurosteez]

evil hondata. I wonder if their tunable program(out in feb) could help this?

[Quicksilver]

Originally posted by myeverlovinsir
Hmmm, sorry to say but that's about what I would expect. Last year we did the exhaust tests on the dyno. Stock flows fairly well. Velocity in the exhaust goes down as you increase the diameter and so does tq. I don't recall anyone testing out a 2.5" mandrel bent pipe, but I know that the 2.5" crush I tried last year showed about the same losses, especially in the tq resonating area of the curve. (~4500rpms). Again, 2.25" crush bent is the largest you want to go NA. Even Joey's 2" mandrel bent pipe showed no gains compared to the 2.25" crush. Which are about equivalent seeing that the crush bends inside neck down to near 2" anyway.

I think you might have been mislead if someone told you that you would get 7hp from the flash. Last year I could not show any gains from 3 EP's stock/modded and then Hondata. Doug was puzzled then and probably still is. I seriously doubt that any dyno results one way or the other are attributable to Hondata.

How is the driving experience?

Here's the promised dyno printout:



As far as losing power with the Comptech exhaust, how is it that people like 02SilverSiHB have shown gains running I/H/E vs. I/H? I'm sure there is a chance that I could lose some power with less backpressure on the exhaust, but 7 hp?!? It just doesn't seem probable.

I keep up with the dyno-related threads fairly regularly, so I've seen what you and Joey pioneered for EPHatch. I also saw where all three of you dyno'd before and after result with the Hondata ECU. I know that at the time there were problems with detonation and nominal gains and losses depending upon who's car it was. But if you look at Hondata's own dyno results, there should be at least 2-4 hp gains at the top end. I don't recall the person's name that got their car dyno'd before and after, but they showed around a 7hp gain on a Bosch dyno. Results got even better with a better intake.

Throttle response has stayed the same, both part and full throttle. (i.e. no changes according to the "butt dyno") The only benefit that I've seen is the raised rev limiter. After about a month, I've also seen my gas mileage go from approximately 28.5 mpg, down to 26.5 mpg. I'm not sure if it's the same priciple with our cars, but on MAF sensor(mass air flow) equipped cars, when you open up the intake, you'll generally lean the car a bit. If you open up the exhaust, you'll richen the car up. I'm just wondering whether I've richened my car up due to the exhaust upgrades and it needs to be leaned out to get me the power back. Hondata does say they were tuned for intake only, but would work correctly with other mods as well. Am I way off base here? What do you think?

[siver-SI]

Well I would say see if you can use someones OEM ECU and try that in your car for a run. That way you know what is losing you the HP.

[Quicksilver]

Originally posted by siver-SI
Well I would say see if you can use someones OEM ECU and try that in your car for a run. That way you know what is losing you the HP.

I e-mailed Doug at Hondata for his thoughts. Hopefully he can find some free time to help explain the poor results. I'll wait to see what he says. Maybe they'll cover the cost of another dyno run using a stock ECU and see if we can find something.

BTW: Anyone in the East Bay (Northern California) interested in getting their car dyno'd should check out Modacar. 3 baseline dyno runs, including a/f ratio, for $40! That's a bargain in my opinion.

[Quicksilver]

I've put my crush bent mid-pipe/stock muffler combo back on. I'll see if I can schedule a dyno run for next week to see how it affects the numbers. There's no doubt in my mind that I've gained back some significant torque in the low end (2500-3500 rpm range), because I've got no more bog down there. Elsewhere, it's too hard to tell. It's also nice to have the exhaust no longer making a bunch of noise and drowning out my bass.

I heard back from Doug and here's what he had to say regarding aftermarket cat-backs and performance:

I have also seen replacement exhaust systems produce less power than stock systems because they are more restrictive. Yes, more restrictive, and noisier. Last week I dynoed a greddy trust catback making 20hp less than a stock exhaust on a Civic type R with Toda cams. In the US I saw a Magnaflow dyno 25hp less than a stock exhaust on a supercharged RSX. In both cases the internal diameter of the rear muffler was about 3 -4 cm. You could see this with a flashlight looking up the rear of the muffler. A restrictive exhaust will drop economy.

Hopefully that is where all my power went. Only the dyno knows... :D

[anjapower]

hmm...I have a comptech exhaust too....

btw, to add more food for thought, 02silversihb dynoed his car with and w/o the comptech exhaust he used to have, and lost 18whp when he DIDN'T have the exhaust on.

[Quicksilver]

Originally posted by anjapower
hmm...I have a comptech exhaust too....

btw, to add more food for thought, 02silversihb dynoed his car with and w/o the comptech exhaust he used to have, and lost 18whp when he DIDN'T have the exhaust on.

He must have cursed it before he sold it, because I'm the new owner. :D

[Quicksilver]

I went back to Modacar to schedule another dyno with the crush bent mid-pipe to try and figure out of the exhaust was the problem. They bumped an Accord exhaust install (since the car wasn't there yet) and got me on the dyno right away. As many conditions as possible were the same. I'd reset the ECU in the morning and let it idle for 5 minutes, drove the same distance, at the same time of day, and under similar weather conditions, and they got my car strapped down and run with a similar cool down period. (Not as clinical as Hondata's recommended methodology, but effective enough)

Here's what we found out. From 4200 rpm on, the Comptech exhaust best run beat the crush bent mid-pipe run by approximately 1-2 horsepower until the 7700 rpm redline. Other than that, the power was spot on compared to the last runs. It was kind of odd too, because even the air/fuel ratio stayed right on top each other on run 2 of 12/23 and run 2 of 12/29. Runs 1, 2, and 3 had some variance between them though in the a/f though. Really weird. Each set of runs within each day was very consistent on all three runs though. No major power variances between any of the runs.



I'm going to shoot another e-mail to Doug and show him the results to see what he has to say. Maybe someone beat the crap out on my car during the 25 miles of test drives before I purchased it? I'll never know for sure. It's just frustrating to have invested that much time, money and effort into all those parts to only be running 144 hp and 124 tq.

On a positive note, because the owner of the shop was so interested in finding out where the missing power was, he was the one that got me in right away. And after I'd shown him the dyno sheet and talked with him a bit about the results, he was nice enough to write me up a "free dyno" voucher on the back of a business card. I think he felt bad because I'd paid for the separate runs to figure out that the exhaust was not causing the power loss. He was also perplexed as to why my numbers were so low. He felt that their DynoJet was about average (or maybe even slightly higher) in it's results when compared to other DynoJets.

I think it's either time for me to go forced induction, or buy a G35 or maybe an Evo. This lack of power really sucks! At least my car handles great...

[02SilverSiHB]

yes I am still pissed I sold that exhaust! by the way, did you know comptech makes a silencer for it now if you need it at anytime? check out their site, it's only like 30 bucks.

By the way, it may be your rotational mass thing, never know. Do you still have the stock rims...but then again, you said you have the brake kit, so I assume it's a big brake kit? think it is, if I remember.

Well, this sucks though, now I'm not sure if I care for the hondata :(

[Quicksilver]

Originally posted by 02SilverSiHB
yes I am still pissed I sold that exhaust! by the way, did you know comptech makes a silencer for it now if you need it at anytime? check out their site, it's only like 30 bucks.

By the way, it may be your rotational mass thing, never know. Do you still have the stock rims...but then again, you said you have the brake kit, so I assume it's a big brake kit? think it is, if I remember.

Well, this sucks though, now I'm not sure if I care for the hondata :(

I knew they made a silencer, but then you're creating a new bottleneck (in most cases) and losing some of the power you gained by adding it.

It could be the rotational mass, but I shouldn't be losing about 5-10 hp from switching to mildly lighter 17s. Honda Tuning did an article when they increased the tire/wheel diameter and weight by 9.5 lbs per wheel and only lost around 5-6hp on a something like a 118hp car. I kept stock diameter and lowered the tire/wheel weight by 1 lb per wheel. And, yes, I'm running the Wilwood 12" brake kit (2-piece hat and rotors). Being that is saves 1 lb over stock, but does throw the rotational mass out slightly, it should be close to a wash in the power department.

My best guess at this point is that the power was down on the initial (Dyno Dynamics) dyno and that their Dyno Dynamics to DynoJet translation factor of "Dyno Dynamics numbers x 1.15=DynoJet number" could be overly generous. Maybe if it's multiplied by 1.1 or 1.12, that would be a more accurate number. So Hondata may not be the fault in this equation. It just seems odd that I'm the only person that hasn't felt a noticible pickup in part throttle response.

I am glad that I saw a gain with the Comptech. If I'd gone back to the mid-pipe and gained power, I'd have been very dissappointed in Comptech.

[Dunrick]

There is just no way hondata is making you lose that much power. Just doesn't make sense. 17" rims, even though 1 lb. lighter, are still slower than the stock 15" - 2" in size is a big difference, its probably about 6 lb's in wheel weight. Its post like this I hate, because it makes me want to get an a2, but at the same time, they are needed and good posts. I wish ya good luck. Sucks that you should have to pay for all those dynos. Ephatch.com should pitch in for ya.

Seriously, try another dyno place. Thats all I can think of. It just doesn't seem right that hondata is robbing you of 10 whp.

[anjapower]

yea man I doubt its the hondata that is hurting you, because worst case scenario, the flash won't do anything powerwise.

Its disappointing to see such results, and like Dunrick said, makes me want to get an A2. You should be in the upper 150whp area with those mods. I will eventually save up for an A2 myself but I want to see how far I can go with this motor. I have similar mods and I want to hit 160whp. Before I thought it would be sure thing, but now don't know. Although it could just be that your car is weaker from the factory?!?

My setup: AEM CAI, Comptech race header, Comptech exhaust, Hondata ECU flash, Hondata IM gasket. I haven't dynoed my car yet but hopefully will do so in the spring.

[02SilverSiHB]

Originally posted by Quicksilver
I knew they made a silencer, but then you're creating a new bottleneck (in most cases) and losing some of the power you gained by adding it.

oh yeay, I knew that, I was mainly saying that for the just in case it's too loud type of day

Originally posted by Quicksilver

I am glad that I saw a gain with the Comptech. If I'd gone back to the mid-pipe and gained power, I'd have been very dissappointed in Comptech.

darn...then you could have sold it back to me :D

Well man, you never know, sometimes dynos can be flukey. Do you have a 1/4 track near you at all? not sure if you do, that way you could maybe have tested the before an after results with the hondata and all.
But that is sad you don't feel much of a difference at part throttle..not that this could really matter that much, but just curious, what octane are you using?