Your comments on the timing in the lower rpm's makes me wonder... The peak hp #'s I'm getting are around what I would have expected (450ish), but the peak torque seems low, compared to most other guys with pulley/intake/catback making mid 400's. Do you suppose adjusting the timing would beef up the torque in the lower rpm range? From everything I have seen on this site and elsewhere, my setup typically yields something like 450hp/470tq. Perhaps the timing down low is causing the issues with the deflated torque numbers. I realize this won't gain me anything as far as peak hp, but if I'm leaving 20 foot pounds on the table, I should probably look at getting this rectified by someone who knows how to do it. Thanks again for all your help 96, as well as everyone else who has chimed in.
Dynoed pulley/intake/catback; Questions...
- Thread starter kilrb
- Start date
Absolutely it would affect torque. With the difference in timing you could be leaving 20-30lbs of tq and 10-20rwhp on table in the midrange, and 5-10rwhp peak.
Wow, that would actually make my car exactly what I thought it would be when I started all of this... 455/475
Stay tuned. I'm going to call the other tuner I spoke with last week and quiz him a bit. Tell him what I'm seeing in my datalog and see what he says he'd do. If he passes the test, I can take it in and pay him by the hour to straighten it out. He said he could probably work it out in an hour; two at tops.
my car has a commanded 11.8 a/f but it was 10.9 (great curve just rich) and he had to tweek something, hopefully i can find out soon if it paid off.
You command a desired AFR in the tune, then alter the MAF transfer function till the car see's the AFR you were commanding. If it's richer or leaner by a good amount it means the tuner didn't spend enough time on MAF Xfer function.
hey bro...just a lil info about my cobra and how different they are. i'm running pretty much the setup under the hood but with an idler and long tubes headers with my exhaust. after the tune was completed....final numbers were 489 rwhp and 511 rwtq. she made over 500+ rwhp but was running too lean so the tuner backed it back out to the 489. the tuner told me that he has never seen a cobra make that much power with those mods before. so as you can see...all these beauties have a mind of their own in my opinion. =-))
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1. Check to insure the proper belt size and tension. Use a Gates belt IMO...
2. Plugs - NGK tr6 or NGK br7ef gaped at between .32 to .35
3. AF at around 11.6 through the run.
4. Timing at 23 degrees through the run. Datalog to confirm.
5. IAT2 temps need to be around 100 or lower. Put a fan infront of the Intercoller with the car turned of jumper the IC pump for cooler temps.
6. Check to insure that your IC pump is pumping fluid during the run, I recommend that you jumper the pump IC pump while on the dyno.
2. Plugs - NGK tr6 or NGK br7ef gaped at between .32 to .35
3. AF at around 11.6 through the run.
4. Timing at 23 degrees through the run. Datalog to confirm.
5. IAT2 temps need to be around 100 or lower. Put a fan infront of the Intercoller with the car turned of jumper the IC pump for cooler temps.
6. Check to insure that your IC pump is pumping fluid during the run, I recommend that you jumper the pump IC pump while on the dyno.
23* of timing on 91 octane?
Was it Nick that tuned your car? I also had MC tune mine after a Steg stage 4 port. I requested that the tune be very conservative because of the shitty 91 octane oxygenated fuel here in KC. According to Nick the WOT timing was set at 19* and my a/f ratio at 11.3:1-11.6:1. At 14 psi my car made 494/513 with some power left on the table. I wanted to be able to pound on the motor all day and not worry about DOTC. I have since went to a 2.8 upper so I figure my power numbers are up a bit. My only complaint is the driveability of the tune. I plan to have Nick mess with that some more as I'm not 100% happy with it...other than that I'm pleased. BTW, Nick has indeed tuned hundreds of the 03-04 Cobras. Nick came highly recommended by Mark Covey who started MC Racing back in the day.
The guy who did the tuning is Paul. He's got kind of long-ish hair. He's there in the afternoons and evenings. I haven't met Nick. Although I'm questioning some of the parameters set up in my tune, everybody I have spoken with down there at MC has been extremely friendly and helpful. How long has it been since Nick did your tune? Is it possible he left, and now Paul's the go-to guy for Cobras? Have you ever dealt with Super Tune Performance in Merriam? I spoke with a guy named Ryan there a week or two back. He seemed pretty knowledgeable and friendly...
I know who your talking about and I'm not so convinced he is the "go to guy" for the Cobra. I insisted on Nick doing my tune, I was not having it any other way. Paul started the basics of the tune until Nick arrived, then he took over. It does not surprise me a bit that your not happy with your tune done by him, he didn't impress me with his knowledge. He also told me that the knock sensors will save the motor by retarding the timing...I knew no such animals existed on our motors. Paul and his brother are new owners there...I really don't know much about them other than they're nice guys to talk to. Don't know anything about that other shop, can't help ya there. I will say I met a guy at KCIR with a very fast Cobra that didn't speak highly of the tune he received from MC...he also suggested Super Tune. Godd luck, keep us posted as to how you make out.
these cobra pullied motors make peak tq very early compared to other na type powerplants. so, the tune is very important 4000 and below, because that tq will peak somewhere around 3000. here's my 2.76 "only" car with a spot on tune from manny at HPP. the car has run flawless for 20k miles and counting
Damn! Very nice looking dyno sheet! It certainly does sound as though I'm leaving quite a bit of low-end on the table. And the way I drive (not ragging the hell out of the car), that's the part of the tune that is most important; low end grunt.these cobra pullied motors make peak tq very early compared to other na type powerplants. so, the tune is very important 4000 and below, because that tq will peak somewhere around 3000. here's my 2.76 "only" car with a spot on tune from manny at HPP. the car has run flawless for 20k miles and counting
I'll definitely keep you posted on what I find out with SuperTune. Thanks for the intel, man. :beer:
23* on 93 octane. Retard a couple of degrees for 91.
Well, guys, I have an appointment Thursday with another local tuner who I figure sounds worth giving a shot. Worst case I'm out $125 x 1-2 hours. I'll post up results and let you all know what happens...
Holy crap. I'm at the other tuner's shop, and he decided to do a baseline. The car put down just under 400 to the wheel, and about 420 torque. The af was crap all the way through; lean down low, and around 11 up high. Oh, and he noticed lots of belt dust... I'll have to get that idler on order. I'll post up when he's through.
Ok, so the tune session wrapped up, and the timing was taken up to 19.5*. The final #'s were 430/451. This is obviously down in power, and slightly up in torque from the #'s I walked away with from the other shop. However, as I posted a couple of hours ago, the baseline today (old tune) got me 399/425. I did drive 30 minutes to the shop, but it was 55mph or slower, and I didn't take the rpm's up much, so I don't think heat was an issue... I have posted below the "old tune" vs the "new tune" for you to look at. Is there a logical explanation for the huge difference, other than someone giving me phony numbers? Is it possible that the belt is slipping more now that it has been broken in some? I'm confused as hell. I do plan on ordering the 100mm idler pulley, and once it's on, I'll go back in and do a nice cool dyno pull to make sure the tune is still good with less or no belt slip. The guy who did the tune told me he saw the boost peak out at 14psi, and fall as far as 11psi. Ok, so go ahead and give me some "I told you so's."
Old tune today on the new shop's dyno
New tune today
Old tune today on the new shop's dyno
New tune today
Torque curve looks odd, its lacking down low then peaks and drops off rather quickly.
You know, the scale they used today was kind of goofy. Not only is it one where the torque and hp are on different scales, but the range is huge, making the curve look really peaky. I put together an Excel spreadsheet and graphed the original tune from the first shop, along with the two from today, and it's informative... Take a look.
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I have similar mods as you. But I do have a bassani high flow x pipe. I as well think I have belt slip, from the belt they through on. My gauge peaked at 13psi, but on the way home only hit 11psi. I have belt dust and have the 100mm idler on the way. I had a 90mm on there. Just think the belt loosened up a bit and now its slipping. My #'s are SAE and prolly just avg, heres my graph.
Another question for some, if there was belt slip, would it show on the dyno graph?
Another question for some, if there was belt slip, would it show on the dyno graph?
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