tt383lt1

iTrader: (3)

ok today i finally got the car running top knotch. we only hit 10 psi we never cam off of the spring. but it laid down 720tq and 450 hp max

the 720 tq was only at 2700 rpm
the 450 hp was only at 4500 rpm

and we never lost boost until 7200 rpm when it hit the rev limiter

as soon as we hit the 720 tq it started to drop as the rpms went up.
and at 4500 to 5500 rpm we could not get any more hp after that. so we think the converter is slipping bad. and at 7200 rpms we are losing about a 1000rpm from hp tuners to the dyno.


and i drove it on the street after it was done and the thing was so fast i could barley hold it down even after 4500 rpms in middle to top of 3rd gear the front end started to lift and the *** started to float.

so how can a slipping converter pull hard after the 4500 rpm. and on the street it felt like it got faster and faster after 4500 rpms

any input

here is a link to the dyno pull. the pull went to 7200 rpm and the gragh only shows 4500 rpm ( its the only one i can get right now the paper gragh is to tiny to get a good pic of.

tt383lt1

iTrader: (3)

so the question is. is the converter slipping or is it there dyno.( they have a new hub dyno). i just cant beleive how hard it pulls on the street with a slipping converter

J-tuneD

Hmmm, how were they getting rpm data to the Dyno?

Some dyno's have a feature that allows the rpm to be derived from wheel (hub) speed. As you might imagine an auto trans and it's inherent slip doesn't work very well for that.

Or if they used an inductive pickup on a plug wire, they may have simply entered the wrong values in the rpm pickup settings. On my Dynojet you can tell the software that the plug fires every 180, 360, 720 degrees of crank rotation. Choosing the wrong one for the setup will obviously skew the numbers as well.

LS1NOVA

iTrader: (12)

Something is definately "off", that pull is way too long and stagnant for a big turbo car.

tt383lt1

iTrader: (3)

thats what i thought. it was a long as pole. and what do you mean stanant?

J-tuneD

Im sure he means stagnant as in it was basically not climbing in the rpms..

Id say you should find a different dyno..

FASTFATBOY

iTrader: (23)

The car is loaded a LOT differently on the street spinning its tires versus strapped down to a dyno, thats why.

Put slicks on the car and hook it at the track and it will blow through the converter like it did on the dyno.

Timmy2Stage

iTrader: (56)

You are blowing right through the converter. It will make power to a certain point and then the converter will just start to shear the fluid. You need a different stator in the converter. We have used a place called Midwest Converter in Rockford, IL. Ran into same problems before in the past and have picked up BIG mph and et. Give them a call, you won't regret it.

98BuickGS

I believe he found out he had a split intercooler coupler. AFAIK its running good and hard on 15psi.