My dyno run...need thoughts

[99V8SHO]

My dyno run.
I am not impressed at all with the hp numbers, but the tq numbers seem to be surprisingly high. (250 est. at the crank!). Any ideas? Where am I losing hp, and why are my tq numbers so high?

 

[NECGP]

Roman,

Does that match the printout you got with those numbers he has. I thought we took your car up to redline. When I get my computer up I'll check my disk also and verify. That just doesn't look right for some reason.

 

[MilTownSHO]

Doesn't seem to bad, a little under what you would think stock would be..

 

[99V8SHO]

The hp numbers are a little low, and the torque numbers seem a little high. I know they took it up to redline, but those RPMs are not showing on my page at dynoperformance.

 

[AutoSHO]

I'd really like to see the actual results.

 

[Glue Maker]

eek! Mine got 195 FWHP with the K&N (Which was closely fallowed by my upper radiator hose exploding)
Maybe the SAE was messed up? The a$$h013s didn't give me a torque reading, but from SHO dynos I've seen usually the HP and torque are +-5 to each other.

<small>[ November 12, 2003, 07:50 PM: Message edited by: Glue Maker ]</small>

 

[99V8SHO]

Only a K&N and you put 195hp to the ground?? That is insane. Factory freak? I just wish my hp numbers matched my tq numbers. My hp and tq are not within 5 of each other, that is for sure.

 

[NECGP]

Roman,

Dean and I are talking about this and looking into it. Once i get my computer up I'll double check the file and call the shop if necessary. I do remember your results going up to redline and the file Dean recieved appeared to of been cutoff at the bottom.

 

[99V8SHO]

We may not have all the RPMs recorded, but IIRC, 177 was the max hp. Also that friggin blip at about 5K RPMs in third that cost me a few hp. Apparently it is a problem with all gen3s. rant

 

[sdpatt]

That plot is showing only a 1000 rpm range, starting at 4,750 rpm. The output appears to be greater below 4,750. Where's the rest of the data?

 

[NECGP]

sdpatt:
That plot is showing only a 1000 rpm range, starting at 4,750 rpm. The output appears to be greater below 4,750. Where's the rest of the data?

Simple, read up two posts and you will have your answer! wink

 

[SHODOGG]

IMO that sounds about right for a basically stock G3 SHO. When we had our first SHOCAGO dyno day, there were a bunch of G3's there and they all pulled between like 178-195fwhp depending on mods. Most stock ones were in the high 170s or low 180's from what I recall. Torque was always really high, though. Couple guys were over 200fwtq.

 

[Glue Maker]

There is the freak run. The giant spike is the radiator hose exploding (I think)

 

[AutoSHO]

Glue Maker:

There is the freak run. The giant spike is the radiator hose exploding (I think)

Actually, its the torque convertor locking and unlocking. All gen 3s do it around 95(?) mph.

And the car only actually made about 177 to the wheels. The 195 number is coming from the TQ convertor spike.

<small>[ November 17, 2003, 11:52 PM: Message edited by: AutoSHO ]</small>

 

[AutoSHO]

99V8SHO:
We may not have all the RPMs recorded, but IIRC, 177 was the max hp. Also that friggin blip at about 5K RPMs in third that cost me a few hp. Apparently it is a problem with all gen3s. rant

It doesn't "cost" any HP. The blip is normal, and if you look at the graph posted above, you can se it went right back to the same curve it was on pre-blip. If you could find a way to have the Torque Convertor locked like that you'd be gaining about 20 hp to the wheels. Thats why us 5 speed guys are so much faster.

 

[Glue Maker]

AutoSHO:

Glue Maker:

There is the freak run. The giant spike is the radiator hose exploding (I think)

Actually, its the torque convertor locking and unlocking. All gen 3s do it around 95(?) mph.

And the car only actually made about 177 to the wheels. The 195 number is coming from the TQ convertor spike.

They ran it O/D off


~~~~~~~~~~~~EDIT~~~~~~~~~~~

Oh wait, I don't think it will go to 130 in 3rd?

~~~~~~~~~~~~EDIT~~~~~~~~~~~again..

Craptop dyno says it will, but I don't want to test it in real life eek!

<small>[ November 18, 2003, 12:20 AM: Message edited by: Glue Maker ]</small>

 

[AutoSHO]

Trust me, its the torque convertor locking and unlocking. Thats why the spike is there, right around 100. Go look at any other gen 3 graph done in third, it will be there.

 

[RonPorter]

AutoSHO:
Trust me, its the torque convertor locking and unlocking. Thats why the spike is there, right around 100. Go look at any other gen 3 graph done in third, it will be there.

Yep, you are correct, it is very typical of any ATX SHO (and a lot of ATXs in general). That's also why the numbers below about 4,500 or so in 3rd don't mean much, considering the shifts and the TC locking/unlocking. It's a real problem trying to get good ATX power curves all the way through the range.

Folks, the Dynojet only measures torque at the wheels, and HP is strictly a mathematical calculation from the Torque number. These are the basic calculations for all of it:

HP @ flywheel = torque X RPM/5252
HP @ wheels = HP @ flywheel X 0.78
HP @ wheels/0.78 = HP @ flywheel

The "0.78" factor assumes the 22% loss for the ATX, change that factor the "0.83" (17% loss) for an MTX SHO.

Basically, you can't have "high torque but low HP numbers", and HP is not "real"....it is only a calculation from the torque number at a given rpm.

 

[Ian Macoomb]

AutoSHO:
Trust me, its the torque convertor locking and unlocking. Thats why the spike is there, right around 100. Go look at any other gen 3 graph done in third, it will be there.

The torque convertor locks up just after the 2-3 shift. I know that it happens during a 1/4 mile run so it's way before 100 or 95 mph. More like 70-75 mph.

 

[Ian Macoomb]

AutoSHO:

99V8SHO:
We may not have all the RPMs recorded, but IIRC, 177 was the max hp. Also that friggin blip at about 5K RPMs in third that cost me a few hp. Apparently it is a problem with all gen3s. rant

It doesn't "cost" any HP. The blip is normal, and if you look at the graph posted above, you can se it went right back to the same curve it was on pre-blip. If you could find a way to have the Torque Convertor locked like that you'd be gaining about 20 hp to the wheels. Thats why us 5 speed guys are so much faster.

Exactly. My horsepower jumped from 186 to 198 when I ran in 3rd gear vs 2nd gear (the TC doesn't lock in 2nd).

However, I disagree about the 5 speed being sooo much faster. I see lots of guys that are still in the 15's.