Dyno variances

[BADDASSC6]

What do you guys think:

Vette doctors performance built my 416 and tuned it to 530 rwhp. The car runs great. I thought it would have run a little faster than the 122-125 trap speed that it ran at AAA.

I installed a FAST 103 and 102MM TB. We are almost done with the tuning and are around the 450 rwhp range.

The VD dyno was a land and sea dyno. The JBA dyno is a load bearing dyno. Do you guys think that there is enough difference in dynos for the huge difference in power.

[Shaolin Crane]

If its a loaded dyno then very much so. One is probably a mustang dyno and the other is a dynojet.

[Vettezuki]

That seems like too much to me. In my case I ran 380 and 391 on a mustang and dynojet respectively. The car was setup almost identically AIR.

Weren't you at 465 with your previous setup and running 122 traps? If so, that's a fair indicator this engine may simply not be making anywhere near 530 RWHP, which I would think in a Vette would put you closer to 130.

[BADDASSC6]

The first H/C/I ls2 made 490 and would run 118-120. The ls3 stroker made 530 and would trap 120-123, almost 124. I thought it had more in it because it didn't feel like it pulled up top like the ls2. That's why I got the FAST and the TB. The only way to find out is to take it to the track.

[BADDASSC6]

The first H/C/I ls2 made 490 and would run 118-120. The ls3 stroker made 530 and would trap 120-123, almost 124. I thought it had more in it because it didn't feel like it pulled up top like the ls2. That's why I got the FAST and the TB. The only way to find out is to take it to the track. I made more power after they were done then when I drove it in. I will go drag racing soon and see what she traps.

Regardless, I will have to put the car on a dynojet dyno for NASA.

[Vettezuki]

When's that gonna be? The 14th.

[kdracer73]

Hot Rod mag did a dyno compare a few years ago. Same car taken to 4 shops without changes to the set up
http://i925.photobucket.com/albums/ad94/kdracer73/motorgen%20stuff/hrdp_0405_16_zchassis_dyno_guide.jpg

And the whole article....

http://www.hotrod.com/techfaq/hrdp_0405_chassis_dyno_guide/viewall.html

[BADDASSC6]

Not the 14th. Speedventures has a points systems that determines the class. I have enough point to force me into the unlimited class.

NASA is strictly a pounds per horsepower system (when you have a major engine mod). It will be in Jan or Feb.

[Vettezuki]

Hot Rod mag did a dyno compare a few years ago. Same car taken to 4 shops without changes to the set up
http://i925.photobucket.com/albums/ad94/kdracer73/motorgen%20stuff/hrdp_0405_16_zchassis_dyno_guide.jpg

And the whole article....

http://www.hotrod.com/techfaq/hrdp_0405_chassis_dyno_guide/viewall.html

That's what I thought. The spread is not *that* big. 530 vs. 450 is pretty major. Maybe a combo of difference between Mustand and Dynojet and shit hot day vs. a nice cool day? Even that seems a little much.

[injdinjn]

How did they determine RWHP with just the motor?
Is that called a scientific guestimation, like global warming?

There are a myriad of variables between the flywheel and the where the rubber meets the road and every car is different.

[Vettezuki]

How did they determine RWHP with just the motor?
Is that called a scientific guestimation, like global warming?

There are a myriad of variables between the flywheel and the where the rubber meets the road and every car is different.

Not that different. Drivetrain losses for given vehicle combos are pretty well known and the variances might be 1-2%, IOW, <= 10 HP . . . max.

[BADDASSC6]

How did they determine RWHP with just the motor?
Is that called a scientific guestimation, like global warming?

There are a myriad of variables between the flywheel and the where the rubber meets the road and every car is different.

I don't know why you think they just had the motor. They had the hole car. No global warming here.

[Shaolin Crane]

That's what I thought. The spread is not *that* big. 530 vs. 450 is pretty major. Maybe a combo of difference between Mustand and Dynojet and shit hot day vs. a nice cool day? Even that seems a little much.

I know i've seen 60-70hp splits between mustang and dyno jets on the corral and other mustang boards. On the flip side it's the opposite with diesels, the mustang dyno will show more torque then a dyno jet just from the nature of a diesel.

DA, elevation, temp, etc all plays a role in determining what a car will make on a given day. Find one dyno and stick with it it's strictly a tuning device and the most accurate measurement is taking it to the track. Unfortunately, AAA is still closed so irwindale is your only option. Both have their issues, AAA is a notoriously slow track and irwindale is a notoriously fast track. I've NEVER been able to replicate a run I made at irwindale at AAA.

[BADDASSC6]

Is Irwindale is 1/8th mile only. I don't care about time really just trap speed. That's the best indication of power.

[Shaolin Crane]

Yes, 1/8 mile. They're in the works to convert it to 1/4 though

[Vettezuki]

I know i've seen 60-70hp splits between mustang and dyno jets on the corral and other mustang boards. On the flip side it's the opposite with diesels, the mustang dyno will show more torque then a dyno jet just from the nature of a diesel.

DA, elevation, temp, etc all plays a role in determining what a car will make on a given day. Find one dyno and stick with it it's strictly a tuning device and the most accurate measurement is taking it to the track. Unfortunately, AAA is still closed so irwindale is your only option. Both have their issues, AAA is a notoriously slow track and irwindale is a notoriously fast track. I've NEVER been able to replicate a run I made at irwindale at AAA.


There's also just jack asses who don't calibrate their equipment. But see the data table above, the spread is not so big and has been my personal experience going between two reputable shops. Don't modern dynos software adjust for elevation at least to bring everything to sea level. Thought I remember that. But yes an engine can vary a lot but, honest 530 to 450 is a shit ton of difference, to the point I suspect either a) the engine ain't making that much power or b) one of the dynos is not calibrated correctly. Of course it could be a "run" of all those factors adding up to a big difference. :huh: Anyway, what's most important is that it does what he wants in the context he needs it to work. At the end of the day, it's all about ETs.

Group hug?

[Shaolin Crane]

There's also just jack asses who don't calibrate their equipment. But see the data table above, the spread is not so big and has been my personal experience going between two reputable shops. Don't modern dynos software adjust for elevation at least to bring everything to sea level. Thought I remember that. But yes an engine can vary a lot but, honest 530 to 450 is a shit ton of difference, to the point I suspect either a) the engine ain't making that much power or b) one of the dynos is not calibrated correctly. Of course it could be a "run" of all those factors adding up to a big difference. :huh: Anyway, what's most important is that it does what he wants in the context he needs it to work. At the end of the day, it's all about ETs.

Group hug?
I'm only going by the reputable dyno runs from well known tuners. The problem is most of them are spread across the country. Different geographical location play a big part.

When properly set up a mustang dyno needs to be loaded to the vehicle that its placed on, so different cars will have different splits. I'm not saying it is or isn't probable. Just what i've seen

[BADDASSC6]

So it still really bothers me that the car is down on power. I am going to check the new th to make sure its coming full open. That is a possibility. It electronic and I just bolted it up. I hope that's the case and I hope they don't hit me for another $800 if it is and I have to refine.

[Vettezuki]

So it still really bothers me that the car is down on power. I am going to check the new th to make sure its coming full open. That is a possibility. It electronic and I just bolted it up. I hope that's the case and I hope they don't hit me for another $800 if it is and I have to refine.

That's a possibility but I'd be surprised. If the throttle was a new unit and you just plugged into the harness it should just be responding to the the computer.

Now, yours is a full fly by wire setup right? Maybe there's something in the tune that's preventing the computer from commanding the throttle to open up 100%. Just guessing here.

[Damian]

My only advice is to pick one dyno and stick with it. There are too many variables between two different dynos. With my Eclipse, I had 3 completely different numbers on all 3 dynos. I even had a bone stock Eclipse put down higher numbers than me but I smoked the shit out of him at Fontana every time we ran against each other. One run I even gave him a head start.

[BADDASSC6]

I found the reason for the power loss. The Flexible coupler between the TB and the CAI keeps slipping of the bottom of the TB. The TB blade was hitting it about halfway and would not open any further. I will get the car retuned in March and see where she is at.

[Vettezuki]

Rather substantially more I would imagine. Nice to find it's something relatively trivial. :thumbs_up: