shardul

iTrader: (1)

you are lucky you didnot have any fuel leaks. I also pushd my injectors all the way up in the rail the first time. Luckly my friend caught the error.

GT-ER

Log timing and fuel and post it up....the mods aren't the problem. Many people have them.

Bramage

^ Agreed, everyone seems to have touched on the obvious stuff.

If you could post dyno sheets with torque, HP and AFR, it would be helpful (Before After)

Also, any logging:

• Timing
• Boost
• AIT

If you could get something like this, it would tell the story, or indicate a complete mystery

cij911

^^ How in the heck are you only at 82* IAT at 5000+ rpm???? Now that is a nice setup or you were running your car in the antartic ...

Sher Judge

Very interesting

ajm55

Ok guys, here's what I have:

Unfortunately my tuner can't provide me with a graphic presentation of the relevant numbers but he's given me what he has and I've transcribed and tabulated the data.

To recap, the data relates to 2 dyno runs on the same dyno done 4 months apart.

Unfortunately no AFR and boost readings on the first run. As for the AFR readings on the second run, I am given to understand that "255" represents an AFR of "11.8"

Mods with first run: 168mm pulley, long tube headers, decat, EC h/e and tune.

Mods with second run: As with first run plus 82mm t/b, 550cc injectors, TTM looped rail and one step colder NGK plugs.

Both runs were controlled runs done on a load (rather than inertia) dyno. On both runs 95 octane fuel supplemented with torco octane booster was used. Our 95 octane is about the same as 91 octane in the US.

We are at 5,500 feet above sea level.

Any ideas here?

SavMan

Maybe a stupid question but are the IAT's in F or C?

It's just all other data seems to be metric?

ajm55

Valid question. My bad. Iats are F

SavMan

Your boost and IAT data seems a little out of whack, I'm no expert but pulled up several runs my car has had to compare. I would have expected IAT's to keep climbing rather than peak at 2500 rpm and your boost seems to follow the same pattern.

ajm55

I think because these runs are done on a load dyno, IATS are controlled i.e. the car will be cooled down and then loaded to run at a partcular rpm (say 5,000 rpm) for the purpose of extracting the relevant data. Then the car will be cooled down again and then loaded at say 6,000rpm for the purpose of extracting the data. So there's definitely no question of heat soak or timing retardation. The real puzzler is why we lost power after installng the 82mm t/b, TTM kit and colder plugs. If anythng the t/b alone should produce a gain in power, should it not?

GT-ER

Those IAT's are really weird, I've never seen IAT's jump around like that in a single run. Your timing is also pretty low except near redline where it goes up to a decent amount.

ajm55

See my earlier post (No.35) re controlling IATs on a load dyno. My tuner who is astute is adamant that it's neither a heat-soak issue nor a tuning issue and that the cause of the power loss lies elsewhere

SavMan

Has your tuner rescaled the fuelling for the TTM fuel rail (did you get injectors as well?), you could try speaking with Bruce he may be able to give some guidance.
What belt size are you using?

ajm55

Got the TTM (550cc) injectors as well. Jerry scaled the injectors for us. Don't know about rescaling for the TTM rail - didn't realize this was a requirement - but I'll check with my tuner. Thanks for the suggestion

PACougar

I apologize if I missed it in the thread, but have you done a compression test on all of the the cylinders?

GT-ER

It's not...no way a fuel rail will require a retune.

I just read it, I guess I was in the reply screen when you wrote it.

I'm sorry but this isn't complicated, but the way your car was dynoed is unconventional. Perhaps a complete run will give us all the answers though. Do a complete run without stopping in between the rpm segments and get back to us. Just looking at the timing it's 5-6* below where my car has it and that's a lot of power lost.

ajm55

Not since the manifestation of the present issue, but did one earlier this year - compression good on all cylinders. Car's only done about 35,000 miles. Do you think another test is required?

SavMan

So is your local guy modifying the file from Jerry at EC? or are you just running it as standard?
Are they TTM injectors or from EC?

ajm55

Yeah, I gather that dyno runs aren't generally done in this way. I'll try and get an uninterrupted WOT run done and revert, thanks.

I assume you're not running 5-6 degrees above the 19 degree max that I'm running and that you're referring to timing at lower rpms? Anyway, the timing I'm running now is similar to the timing when we did the first dyno run. That being so, do you still think the power loss could be attributable to a timing issue?

ajm55

Jerry modified the stock ECU file to shut the bypass valve, scale the injectors, neutralize the torque limiters etc. I asked him to leave the timing and fueling for my tuner to map on the dyno. My tuner uses a piggyback system that allows for multiple maps. This appeals to me as I intermittently use an octane booster to accommodate for our poor quality fuel. I have the TTM injectors.

GT-ER

Yeah, from 5500-6000 we are pretty much the same ( I still push 20-21* up there ) but below that I'm at 19-20* while you are at 15-16*....that's a decent amount.

Regardless, your car was dynoed in a load bearing dyno and 330kw is what? 440whp? That's not all that bad for a load bearing and bringing your timing up may just get you to the power you want.

I also need to know A/F ratio with more accuracy, don't know if you can supply that though.

ajm55

I was content with 330wkw with the mods I had at the time, especially at this altitude. We've since gone backwards

I'll chat to my guy tomorrow about your suggestions. I hope he can deliver

ajm55

"Problem" solved.

We again reinstalled the smaller s/c pulley and ran the car - made 3wkw more than we had made on this dyno when still running stock s/c pulley, stock t/b and stock injectors - so the mystery continued - loads of head-scratching, dyno-tuning and switching of parts without any resolution.

Then I proposed out of desperation that I take the car over to another tuner who had run it on his dyno about a month before any of the latest mods were introduced. My tuner agreed (also out of sheer desperation, no doubt). I drove the car to the competitors shop - my first drive since installing these mods - it was immediately apparent (from a butt dyno perspective) that there was a noticeable improvement. The car felt much "lighter" and was far more responsive. We did 2 runs in comparable conditions to those present at the time of the previous runs and the result each time was a 25whp gain.

End result. Car feels good and is making the gains I'd expect to see on the dyno with these mods so I'm chuffed. Don't know if there's a calibration issue with my tuner's dyno or if this was simply a traction problem. Dyno is scheduled to be calibrated next week.

Thanks plenty to everyone that made a contribution here. A decent bunch, you guys are!!

shardul

iTrader: (1)

Very Nice!

ajm55

Shard, thanks for your help. I'm sure the smaller s/c pulley is playing a significant role here. I am however out of shims. Did you ever send the extras?

Oh and while at it, I should also thank Jerry for his input