wow with this turbo i made 375bhp on my 200sx with well over 300 torque. my gt28r(baby turbo ) is putting out more power than your big one , maybe becuase my set-up is decent. no short cut v-bands ..... only joking with ya

I had no idea about the v-band adaptor, but it sounds straight foward enough to sort out, with the help of a mechanic...

I also don't believe their RR's tbh. At northampton motorsport I got 260Bhp @ base boost. The Coop has always been getting faster and each RR suggests that, except at PT.

The on road performance just doesn't match the power they say it has. I mean, would you expect a 289Bhp (-12Bhp from the 301 when the airbox is on) Coop to let a really trying E46 M3 get a jump on me at 55, but I'm then able to just cruise by, by mid 4th gear?

Yeah, because mid 4th gear is around 110-115mph (on 5 speed) and he probably didnt wanna stack it.

WF, PT rollers are used as a benchmark generally, because they are dastek rollers.

I personally would stop thinking they are wrong and start planning on how to release the extra power. If the airbox only released 12bhp, i would deal with the exhaust first and Nigels logic is pretty good tbh.

Ross

Doesn't it depend on the setup though, not the quality of the equipment? Northampton motorsport use Dastek rollers too. I think I've been on other rollers at other times though - Sun Microsystems workstations linked up to them?

Welformed - I am actually of the opinion that PTs rollers give deadly accurate wheels figures, but that their extrapolation for transmission losses is perhaps a bit low.

Just for a moment, completely forget the crank power figure and concentrate on power at the wheels. Now compare PTs figures with your previous RR.

FCCUK once had a RR day at G-Force in Aylesbury. My Coupe was running a stock (smoky) turbo and PRV - that's it. It gave 280bhp "at the fly" but about 200 at the wheels. Lots of people left Aylesbury with big smiles and pub bragging rights, but if I had gone to PT the next day, I would probably have been told I had about 230bhp at the fly (but 200 at the wheels)

So who was right?

Flea's experiences are probably the most telling. 429 at the fly at PT and 480 a couple of days later at PowerStation. The wheel figures were almost identical at about 395 (IIRC)

I will probably go to the Coupe/200SX RR shootout in July, and with about 390bhp at the wheels, I'm expecting to see anything from 430 to as much as 480 depending on what extrapolation settings they use.

Don't blame PT for your car having low power - blame all the otehr RRs for giving you an unrealistic (mis)calculated fly figure.

It REALLY is about time we all started using measured wheel power, rather than guesstimated flywheel figures

Yeah cause its that easy Nigel.

Maha Dynometer wheel powers are significantly lower but their flywheel figures are on par with the dastek rollers and others.

It comes down to the same thing again, that RR needs done on the same day with all the cars in attendance for a direct comparison.

Btw, i doubt you and flea have the same WHP figures, as his 1/4 mile is a full second quicker.

Ross

Well this is it. Some people use RR's to given them bonafide results, but I use them as just an estimate (and diag) as it's real world performance that matters. And as I say, I just can't see how a estimated 289Bhp Coop could be quicker at high speeds than an M3... and it's not like I've only compared to these lately either...

I just wonder how much my light wheels screw results (2 Kgs lighter per wheel with tyres than std). I'd expect the extra spin up of lighter wheels to be opposite and equal to the spin down when calculating transmission losses - cancelling each other out.

Sounds like G-force would've given me 330Bhp by that calculation (250Bhp atw @ PT).

I have spoken at length to the MD at Dastek with some interesting observations. The idea behind the Dastek rollers is to produce highly accurate, sensitive and repeatable flywheel figures. He admitted as much that their wheel figures are higher than the industry average which is simply a product of their technology. He had a lot of respect for the MAHA dynos (except on price as they cost twice as much!!) and was happy to concede that they are also designed for accurate flywheel measurement albeit with much lower wheel figures, again a product of their technology. This is in contrast to the American and Aussie dynos e.g. DynoDynamics, Dynojet, Mustang etc. which prefer to work with wheel power almost exclusively.

I have used two different Dastek dynos and consistently put out between 415-425bhp depending on boost level. I have seen 435bhp on the Dastek with pump fuel with 380lbs/ft but in general 425bhp is the max on my current setup as a rule. Regarding my 480bhp run at Powerstation, there are reasons for this and it is has nothing to do with the rollers. The day was 0-1 degrees on a cold December morning. The car was nicely warmed on the motorway and it went straight on the rollers with 1.7bar It was a simple power run, 4th gear all the way reaching 365lbs/ft, exactly the same peak torque as the Dastek rollers. The ONLY difference was the torque didn't drop off very quickly holding it to redline. This was due to a very dense, cold charge on a warm engine i.e. perfect conditions. The car didn't produce more torque it simply retained it longer i.e. more efficient.

Between rollers, especially in the UK, I would not be inclined to compare wheel figures at all. The Dastek and MAHA dynos can differ by as much as 15% at the wheels, in my case this translated to around 35bhp!! As a general rule Dastek read too high and MAHA too low for wheel power but the flypower should be very close all other conditions equal.

P.s. I'm still up for a comparison if you want WF.

Ross

Sure. Pop down whenever you're ready. We can go and hunt some pork(ers).

btw, "MAHA"???

http://www.falkland.co.uk/dyno.html

This is one fairly local to me.

Ross

IIRC, Fleas's very impressive quarter times were achieved on Mavrics Hoosier wrinkle-wall drag tyres and using race fuel

the fact remains that within a couple of weeks of each other, on the same dyno, Flea got about 395 wheel bhp (about 420 calculated at the fly) and I got 390 (405 at the fly)

Well then, i'll just head up to crail with hoosiers and get a 12.35 on my 28r

Ross

Yes my best 1/4s are with the Hoosiers (radial not wrinkle wall) and race fuel. My best time with pump fuel on road tyres is 12.35 @ 118mph.

terminal speed usually gives a better picture of outright power.

End of the day Flea and Nigel both have very well sorted coupe's.

...apart from the snapping belts!

"Flea got about 395 wheel bhp (about 420 calculated at the fly) and I got 390 (405 at the fly)". Surely those transmission losses are well out?

sorry but saying you beat a m3 so the rollers must be out is mad!!!????? welformed i have been telling you for a long time on the road doesnt mean a lot so many differnt things can happen , his car running bad , the bloke cant shift gears at redline , might be shifting at 5000rpm , bloke not 100% best driver in the world and maybe doesnt want to push his car to the limits but only to where he feels safe . i have seen funny things on the roads past week a saxo beating a s2000 down some twisty roads and as i got to the end of road he had spun out onto grass looking like he just shit himself, why not becuase the saxo is quicker or a better set-up car but the fact that the bloke was a better driver .........

Yeah I know. But you can only go by what happens. The M3 was clearly an auto (double kick-down was obvious), so that eliminates using or changing gear properly. And I'm pretty certain he kept it planted as he wasn't best pleased to see me go past!

I'm sure I'll get comparisons against other stuff in the near future... ... and that is where you start to build your real-world picture.

I've also played with many M3's in my time in various states of tune. They can't all be sick or not being driven properly, yet the performance of all of them was very consistent - certainly when I know I am consistent. Before these mods it was almost dead even until +120 speeds, now with the car running higher boost, feeling significantly faster, it's a different story so far. 289Bhp (IMO) just doesn't explain that at all. Not even close. 320+Bhp would be more like it...

Looking at my graphs I have one that shows 392 @ wheels and 420 @ fly so a transmission loss of 7.2% which is common for high powered cars on a Dastek. My highest run was 398 @ wheels with 435bhp which is 9.2% loss. Nigel, I think you must be out on your wheel figure as that would be a loss of only 3.8%

Welformed your transmission losses equate to 12.4% which is still lower than the industry average but to be expected on a Dastek.

Well i was 16.5% loss....

http://s19.photobucket.com/albums/b176/h2ypr/?action=view¤t=tmp86.jpg

Ross

Those losses still seem way too low. Anyone know what the official transmission loss is on a Coop as std? Yours looks about spot on tho Ross.

That depends on the rollers used...

Ross

That's the point. Transmission loss is transmission loss. It's only supposed to be working out the resistance when free-wheeling from the redline. It will vary car to car of course - with light wheels I'd expect my transmission losses to be lower than std.

It should be as calcuable as WHP and FHP.

It will vary on different rollers as they all use differet technology i.e. singe drum, twin drum, twin rollers, braked. With a twin roller the tyre sits in between, this can be deeper on some and the tyre also get's pinched more. These all affect transmission losses.

The only figure you should be interested in and that can be accurately measured and compared is the wheel horse power.

It's the power at the wheels that moves you not the power at the flywheel.

The rolling road I used here takes the wheels off and the machine bolts directly to the hubs. This avoids any slippage, tyre pressure or pinching issues. The weight of the wheels I think will only affect accelleration.

You can just as easily compare different mods using the wheel horse power. However you can't compare against another cars flywheel figure (manufacturers or calculated/estimated).

John

TBH, I don't think PT's rollers are that conservative. I got 317 BHP with a GT28RSR and a boost leak. I also have the benefit of comparing a std. E46 M3 back-to-back with the aforementioned Coupe and the top end of the M3 and N/A throttle response is better, although no match for the 1.4 bar on-boost midrange of the Coupe

What is your spec as from what I have read so far the turbo is overkill for your setup? I think the GT71R is for people who have gone all the way with their 2.0. You would be better of with changing to an RS.

i have the a gt28rs with the blue flame from turbo back

with the vband adapter and one of timpeons fmic and i had

my car map at pt and managed 340bhp fly 295bhp wheel figures

with the boost set to 1.4 on my avcr but doesnt see 1.4bar

on the gauge tho and it drops off to just under 1.2 and my

car dont stick around,would i be able to make more power

with the H&S down pipe not that i want any more power on my

standard internals,but to be honest i didnt think no one

ran the 2871r on standard internals and i cant beleive you

dont have a fmic or a air filter,they are a must on a

bigger turbo

he does have a FMIC now, pro alloy...

So you have the 5 stud 2.25" vband adapter?

See even with this supposed restriction and the airbox, my car doesn't seem to be making the power or torque it should.