I have approx. 480hp or better going to the rear wheels and i cant get the truck out of the 12's (best so far of 12.34@110 to be exact w/ Jim from jdm driving)
the truck has a MP blower, full exhaust, PI 2400 converter, FTVB, 50lb injectors, C&L upper, single blade t.b, afco heat exchanger, SCT big air mass air, anderson ford power pipe, SCT 4 bank chip tuned by jdm, nitto's, lift bars, & a 6lb lower, & jdm e-fan.
I dont get it, with this kind of power I should be able to run high 11's.
The truck ran 12.4 before i did the torque conv., blower, e-fan, & heat ex.
If anybody has any thoughts or suggestions as to what might be wrong please let me know( yes I will be going to see Jim but I know it's going to be costly so i have to scrape together some cabbage for that visit, the most he told me after running the truck was that it felt soft off the line...belt slippage? )
any help will be greatly appreciated

 

I think your having the same prob. as I am. I dynoed at 485rwhp and 560rwtq @ 17psi with a KB on a stock block. Took it out to the track and was only seeing 12-13lbs and the boost gauge was doin a little dance for me. The weather cond. were about 71deg. and very humid. Had water coming off my tailgate when I went to put it back on. The truck still pulled a 12.05@111. I just orderd a MP idler bracket and pulleys from Jim so hopefully this will get me into the 11's.

How much boost were you seeing on that run? Was it the same as on the dyno?

Chad

 

It's either in the tune, tranny, or the boost is not the same as when you dynoed

Rich

 

That's why Dyno #'s are cool to look at but don't really mean much. I only dyno'd 484hp on my stock block, KB with 17#'s of boost and my best was 11.49@ 118 with a 1.66 60'. You may be having belt slip or tune issues, then again your truck may not be making the power that you think. Some dyno's read higher than others.

 

Are you guys missing the MPH??? That should get you into the 11's! Go with some slicks instead of the nitto's

 

Whip,

You need to see higher than 110 to dip into the 11's. 112-114 is usually a 11.9x run.

If Jim drove the truck, I'm sure he has a good idea of what is wrong. What was your 60ft. I have nittos to run on the street but IMO, they are junk at the track for the mods you have. Too much power.

With your mods you should be seeing 1.6x 60's.

I notice you didn't post anything about suspension. Rear adjustable shocks will make a HUGE difference if you are running a convertor with traction bars.

Get yourself some slicks, some rear adjustables and see what happens.

What was your torque numbers???

If you are running the same tune for an eaton , then swapped a Mag on there, i'm sure you are way off.

Your truck should run 12.0's with that setup. Maybe 11's depending on where you are.

 

i have 500hp/600tq i went to JDM day and only ran a 12.2@110mph i should have been in the 11's too but i didnt have the oppurtunity to do so do to me launching hard i blew both slicks at the 60' mark.. our trucks need a diet..

 

in response to tallimeca, the truck is making about 580-590ftlbs of torque,( i dont have the dyno sheet handy)and other than the traction bars, i removed the 2nd to last leaf spring, with this setup the best 60ft has been mid 1.8's .my most updated tune was done after the MP install was complete so its tuned for the proper components
i did notice that the boost at WOT was only about 15-16lbs and i seem to recall Jim saying max boost when on the dyno was around 18-19lbs
ahh sh@t i dont know you guys are probally right about the slicks they will alow me to be more agressive off the line, and one of those idler brackets might come in handy
thanks everyone for the input, i just wish i didnt have to spend approx. $4000 all said and done to gain one tenth i guess maybe im expecting too much...thanx again

 

NATAS, what did Jim tell you?

Peace,

Suavy

 

im putting 16# boost im running slicks with the JLP traction bars i have the stock leafs with the eibach pro lowering kit.. at JDM Day i had my best 60' was a 1.69... good luck..

 

i couldnt get a good 60' till i soften up the rear shocks and ditched the front sway bar

 

suavy, i didnt get down to talk to Jim yet, but after the run he did say it felt soft down low but top end felt strong.
aaarrrgghh!!!!! this is gonna drive me nuts, especially now that the end of the season is here and I'm not realy going to be able to get much satisfaction track#'s wise untill next year to see if I can better things
thanx

 

Painful I know. I spent 9k with too many bolt ons to list and a KB. 16lbs boost, 12.1 a/f (safe tune) 496/562 at the rear and only 12.2 at 111mph, mind you with no stall and terrible 60 at 1.8.

I really felt I should be in the 11's and John at JLP said get the stall and you will be there. Never had a chance to do that before I sold the '03, but man I wanted that 11.


D-Day

 

Breaking 11s suspension plays a key factor, If you take the 1.8 60 that Ed is getting and change it to a 1.6 thats the difference in a 12.3 and a 12.0-11.9 pass right there. Now we think Ed may have belt slip and if that is it that could be hurting a tenth maybe more.

Ed,

Because I know whats on your truck Id suggest

28" hoosiers
QA1 rear shocks
Maybe a MP bracket or just bring it by and see if we can come up with a good idea for it.

That should be able to get a 11.9 pass with good conditions and 60 foot. You are right on the edge of getting there just the little things that sometimes hold you back. The power is there, getting it to the ground tho is sometimes harder than making it. I also just spoke to my Dad and he said there is some room in your tune too.

JimIII

 

I'm not to the level you guys are at, but maybe some of you are having the same problem I'm having with too much Torque Convertor slip. Every body looks at the Torque converter flash stall speed but never at the slip under full load. I'm told this should be about 200 RPMS or so when working correctly. If the average engine RPM in the powerband is at 4800, you would typically expect 200/4800=4% power loss under load. I my case I was seeing up to 700RPM slip under load, 700/4800=15%. The average slip I was seeing was around 400 RPM on a 1/4mile run. That worked out to be about a 8% power loss. So out of my 420RWHP I was only putting about 385 of it to the ground.

The thing about converters is that the more load you put on them the more they slip and the more power you lose. I'm in the process of trying out an idea of tuning on mine for the TC to lock up shortly after launch whenever the TPS is over 75% or so. The only thing I'm a little worried about is what this is going to do to the shifts since the transmission will be firmly linked to the engine.