My Dyno!
 

The SLC Rotary club had a dyno day today so I gladly paid my 50 bucks and threw my 8 on it!

Found out something rather interesting, might have already been posted but I don't care.

I have an RE Intake and by the numbers (only compared to the average RX-8) the intake lost me a lot of mid-range torque.

I don't have a scanner here so I'll post it and scan it later.

Me (3/13/04):
Max Power: 169.4 @ 8200 RPM :)
Max Torque: 123.9 @ 4200 RPM :(

Base run (bone stone, 3/5/04):
Max: 167.1 @ 7300
Torque: 136.2 @ 5700

There was another 8 there maybe he'll post his results.

I will take off the RE intake and run a dyno with just the stock and then run it with the K&N drop.

oh btw this was just 3rd gear pulls.

-guy:D

hmmm very interesting...

So the airflow is restricted, so it could be really good at either higher rpms... free way driving, or with an exhaust.

WOW its depressing looking at the max power it gave,and you had a re intake . i was planning a dynoing mines but the shop dyno was having problems i see if i can get to them next week. ill go cry now

I don't have a RE intake, but will be dynoing w/ Chuck @ RE next Thursday or Friday stock and w/ the RE intake. I'll post results when done.

William

I was the other 8 at the dyno day. Car is all stock except for Redline MTL in the trans.

P: 168.2 @ 8000
T: 135.8 @ 5200

Mark

I'm curious. Did either of you who dyno'ed your cars do the "limp mode" trick? those numbers are quite low.

I think they're at like 4400 ft altitude too, which makes considerable difference.

I think if I have to read one more "Dyno" thread I may just kill myself..the car SHUTS DOWN ON THE DYNO! please, use the search function and learn!

Both stock cars runs were very close. Close enough. The intake equipped car had much less midrange torque. I'd love to see the dyno plots overlaid. 2 peak horsepower gain with a sacrifice where the car is driven 99% of the time doesn't sound like a good investment to me. The stock airbox is tuned. Now the tuning is gone. The added airflow doesn't show an apreciable, feelable gain on the top end. I won't rule out the fact that the results are from limp mode though and indicitave of the true potential of the intake.

I too would like to know if you guys did the wheel sensor trick though to fool the car so it could be dynoed. The 4400 ft altitude still corelates well with those at sea level when you factor in air density differences.

Jercs:

If you want to put your car on the dyno again. I have a series of tests for you to run. I will pay $100 toward your runs. Email me at rotaryextreme@aol.com so we can discusss this.

Chuck Huang

These were fairly quick runs, so nothing was done except to turn off the DSC.

Salt Lake City's airport is at 4227 feet above sea level.

I can't post pics but I have the graph that compares the two runs. Basically, Jercs' 8 was at or below mine until right around 7200 RPM, the point where the last intake valve opens. From 4200 - 7000 was where the biggest differences were.

Mark

What kind of dyno did you use?

Unfortunately, those numbers sound quite familiar....

A Mustang dyno.

As far as these numbers go, just insert the typical "I love this car" comment here. Besides, on road experience has shown me this car runs about the same as others with similar rated power.

If you look at the CZ dynojet the whp of stock rx8 was around 169. Also i thought i remembered hearing that base mustangs and gt autos had bad gearing for their power.

Insert "I love this car" too :D

I'll talk with the tech at the garage about all the dyno things you guys have said.

-Guy

Still kind of a waste of money, don't you think? If you know that the ECU goes into a safe mode and restricts power on a dyno without doing the limp mode bypass (wheel sensor tricks) - why bother? It's not a real, valid number...

Regards,
Gordon

well its a good base number to start your mods from.

If we always do it the same way it's a good base number to work with. And since all the 8's this garage were done the same way it (if nothing else) shows about the intake. Now maybe with the test Chuck will give from RE, it'll correct itself.

A mustang dyno reports #'s about 15 pct less than a dyno jet, FYI.

And the tech at the garage told us that the Mustang was more accurate and the dyno jet reported high numbers that weren't real.

I don't see how this can be. If in fact the car is in safe mode and the car is dumping fuel/retarding timing/doing whatever it can to be in safe mode, any changes made to the engine will just give you a comparison against the safe mode base. What does leaning out the mixture with a piggyback or changing the air intake and then testing it against a safe mode setup tell you?

My point is 90 pct of the dyno's you will be comparing against are going to be dyno jets, so when comparing a dynosheet of a mustang dyno to a dyno jet factor in a rough 15 pct.

FYI, a dyna-pac will measure less than a mustang dyno or dyno-jet and they will tell you that a dyna-pac is the most accurate.

i say its all a crock of crap and the only way to judge and get an accurate real world estimate is take your car to the drag strip and get a before and after trap speed.

Agreed. But if we use the same one to compare mods it should be fine. I was posting merely to show my results I found with the RE intake. That based on these numbers, I was below average torque in the mid range. The numbers I could care less about, I didn't buy this car for the HP!

Chuck and mentioned doing more tests, so we'll see what he wants to do. Plan to use the same machine to give correct feedback. I think I need to dyno with the stock intake in and re-dyno with RE in.

read the other posts after mine. any percentage change shown on the dyno is a percentage change, whether or not the car is in safe mode or not.

I agree completely. This is why I asked in the first place. I guessed it was most likely a mustang dyno.

A mustang dyno is a load generating dyno where as the dynojet takes less effort against the car once the drums are rolling hence numbers that can not be compared. Which is better is pointless.

The important part of going to a dyno is to compare numbers before and after a mod to see gains and for tuning.

For a real comparison between cars and power, I could not agree more about going to the track. Your trap speed can tell you a lot.

For comparison, on a dynojet, that number could well have been in the high 180's or low 190's.

Why do we assume this car went into limp mode anyway? I would like to see this for myself. I really need to go to a dyno.

Chuck, what was your experience with this? I am interested in hearing from someone who lives near me with their own dyno experience. :)

I dyon'd 161rwhp on a mustang dyno, and trapped 92+mph. If thats any concern to anyone. CJ

I've never dyno'ed any car, but my 8 is easily the quickest of them all. All I have to say is keep the revs high and floor it to quickly cut around slow people in the passing lane. It's so much fun.

I got the list of tests to do with the RE intake from Chuck. I'll be doing that soon, I'll post my findings as soon as I get them.

Here's my old dyno sheet with the RE-Intake VS stock (mines "test" run)

http://www.vivanetcorp.com/guys_work...fall/dyno1.jpg

Here is a run in my stock 8 with a stock cat back. :D

Cat back installed. ;)










Ok, this is'nt my Rx-8...but my 7. I hope you guys don't mind looking at my single turbo dyno sheets. :) CJ

I couldn't tell, i thought they made rx8's back in 99 ;)

Actually, those where done last Friday. The guys at Groundzero motorsports, must not have the correct date in the computer. Some nice numbers though huh? CJ

52hp gain w/ just catback?? Highest numbers I've seen, (probably ever see!)
Redline in the 8's is 9,000. Tell them to rev it longer.

Um, I think those graphs are for his 93 FD, not the 8. That's an shitload of power, btw!

JECS. I posted the result at the following link

http://www.rotaryextreme.com/rx8dyno.html

Chuck Huang

>read the other posts after mine. any percentage change shown on the dyno is a percentage change, whether or not the car is in safe mode or not.

It sounds good, but that is incorrect. If the ECU changes the timing or A/F ratio in any way (for safe mode), that will effect other parts of the system quite significantly. Same for other changes by the ECU.
Lets say you were doing a fuel map change and the ECU goes to "safe mode" by richening the mixture (just a basic example, im not saying it does this). If you got a 5% hp increase of by setting your mod in place, you cannot assume that the 5% will happen if the ecu doesn't richen the mixture. There is just no way to know, too many variables etc. Even airflow is effected by minor changes. It would require a proper test.