Yes, drag losses vary depending on tyre compound, pressure, wheel size (double contact patch also unrealistic). Ambient temperatures on the rollers, heatsoak, length of run. Brakes can be dragging. Some rollers seem very consistent for PaW, others for flywheel. Some you get better figures on a second run as the transmission is warmer. On others the second run has too much heatsoak. Absolute minefield. Your power at the wheels is very respectable indeed. I just mapped a decat P1 and whilst it gave 309 BHP on a conservative dyno it got less than your PaW, but 289 lbft. Which car is faster? Hopefully the mapped P1 (merely because of the work done on it), but who knows from the dyno results! Different dyno, different day etc etc. In the same way it is possible to make mods that actually lose power and torque look like they gain it by the way the car is setup!

[Edited by john banks - 9/4/2002 8:01:13 AM]

 

Just got back from Owen Developments after having my Type R run up to check all is functioning OK.
Couple of things to mention............................

WOW................................
What a set up they now have. Their new 4 wheel dyno is the business. The fans in the cell are immense. I tried to stand in front of the car when the fans where on at 50% and couldn't hack it.
Most impressive was that we ran the car for 7 runs and it didn't run hot one bit.
Infact it stayed the same temp as when usually cruisin around in general. Truly superb.
Also the rpeorts that are created are fantastic. Got printed maps of my boost, intake temps, bhpo, torque, air/fuel etc etc

Anyway ,as mentioned the purpose was to check various settings etc and not to tune it at all. Basically checking the car was 100% to start modding!!!! Remapp is due at the beginning of Oct.

Anyway the results were mixed.
273bhp @ flywheel @ 7100rpm (223bhp @ wheels)
230lbft @ 5200rpm

The horsepower was pretty much as expected although the torque seemed low to me. I am not sure what the stock torque figures are although I think they should be about 250lbft.
Boost curve was smooth along with the power and torque curves. No real hickups etc etc, although plenty to work on fo the remap to gain on the real roads.

My car is a stock Version 5 Type R , with the exception of a scoobysport downpipe and a blitz exhaust.
I am running Water Injection at the moment so anticipate figures to be slightly lower than usual until it is mapped properly( Water replacing fuel etc etc)

I am wondering whether the lack of back pressure with this aftermarket system and downpipe has robbed me of the torque.

We had other cars to compare on the dyno and they were hitting the antipated figures bang on!!!

Any ideas or thoughts are greatly appreciated....................

 

Have I posted this to the wrong list for advise??????????????????????/

 

RR results are subject to so many variables I personally don't think you can read that much into them. I also don't think that low exhaust back pressure after the turbo is a reason for losing torque unless the map is way out as a result.

 

John

would I be right in saying the only true figures are the power at the wheels . Both flywheel and torque are calculations from this info???

 

Yeah I agree with your comments of RRs in general.
It used to annoy the **** out of me when I was an MR2 Turbo owner , as so many people on the list were hung up on dyno figures. I think we should be more like the US and perhaps focus more on HP @ wheels figures. It seems that is all they ever quote over there!

I really only use the RR to compare mods when they have been done and even then as you say , different day , different results. I try to narrow it down by doing before and after on the same day and also use the same dyno.

But they vary so much from tuner to tuner.
I had my MR on the old 2 wheel dyno at Owens a few years ago and it put out 271bhp and 282lbft.
Took it to a shoot out down in kent the very next day and their dyno read 292bhp and 271lbft!!!!!!!!!!

Anyway I am looking forward to getting the Unichip mapped to see what the car is doing after everthing has been reconfigured properly.

 

IMO, ATW's figures are just as unreliable as flywheel figures. They vary just as much, from one dyno to another.

223bhp ATW's for a stock car is very high, whilst 50bhp drive train losses are very low.

273bhp for a basicly stock car, is a little on the low side, but more accurate than 223bhp ATW's.

As a reference, cars making 235~245bhp ATW's at PE, will be making circa 345bhp flywheel on the same dyno.

What gear were your runs done in. I suspect they were done in 3rd.

Mark.

 

Mark

Runs were predominantly carried out in 4th although a couple were done in 5th. How does this effect it? (Sorry not very technical)

100-110bhp losses through the transmittion! Is that usual? Thats over 30% loss. I know 4WD cars lose more than 2WD however didnt realise they were that much!! Was expecting approx say 20-25% perhaps,

I know most on this list say that an STI with D/pipe and full system should see around 300-310bhp. So baring this in mind would 224bhp with average expected losses not work out to approx that?

Don't get me wrong , I am not arguing with your comments. You have far more experience with Scoobys than me, and my knoweledge as you know is very limited.
Its just over the last 10 years I have used many RRs (PE when I was an RS man, Interpro when I was a Cos man and Owens in recent years) and they all vary so much its rediculous.
My RS used to read 15% higher on PE's dyno than anywhere else, but I wouldn't let anyone other than Merv at PE touch it!

My initial feelings from yesterday were that the bhp figures at the wheels seemed pretty accurate , bearing in mind the mods but the torque seemed very very low, and I am unsure why this is as all readings seemed there or there abouts.

 

I'm no dyno expert. The info is just based on runs taken from the Dyno.scoobynet site, linked at the top of the page, Aus' RR figures, and my own experiences.

On average, losses are circa 100bhp, with cars running this level of power.

Now, look at it this way. Your car should have circa 276bhp stock, which would generally give 170bhp~180bhp ATW's (most RR's).

You got a figure of 223bhp ATW's, some 40~50 bhp up on what would be expected, and you'd expect to be at least 40~50bhp up on the flywheel figure.

I also know from experience, that new RR's take a little time to get set up. I was the first 4WD car to be run when Superchips got their new RR, and the first runs were giving about 220bhp flywheel, on my tuned STi4......

They did some software changes, and that gained 40~50 bhp (iirc) then they adjusted the distance between the rollers by just 1cm, and that gave another 20bhp !!!!

Personally, I would expect it's a similar thing with the dyno you used.

Mark.