What BHP when running BPU.

Ok all, im BPU but not had a chance to get it on a rolling road to find out the performance. Boost goes to 1.2. Any idea's of what it would be??

Auto? Manual?

Autos, usually between 290 and 310 at the wheels on a rolling road or between 350 and 400 on a hub dyno like Thor's.

Auto? Manual?

 

Autos, usually between 290 and 310 at the wheels on a rolling road or between 350 and 400 on a hub dyno like Thor's.

lol, funny!

lol, funny!

Manual mate. so im looking at 400bhp then?

Huh? What's funny?

Ahhh, miss read slightly.

I read it as there would be an extra however many HP @ Thor.

Not 400 at the wheels, that would be very unlikely.

My BPU auto makes 300rwhp on a RR and 350.5rhhp on a hub dyno. A manual TT should make a little more but not a huge difference.

You can claim 400 flywheel from just 270rwhp if you like, just allow 33% losses. A lot of folk's flywheel bhp claims are unrealistic.

Ahhh, miss read slightly.

I read it as there would be an extra however many HP @ Thor.

Indeed, my car gained 40 rw 'X' p on their dyno

Not 400 at the wheels, that would be very unlikely.

My BPU auto makes 300rwhp on a RR and 350.5rhhp on a hub dyno. A manual TT should make a little more but not a huge difference.

 

You can claim 400 flywheel from just 270rwhp if you like, just allow 33% losses. A lot of folk's flywheel bhp claims are unrealistic.

I claim 25% losses on an auto. Only cause it give me a pub figure of 500bhp lol. If im talking to people who know what they are talking about its 380RWHP.

There would be. The Thor dyno is well known to be rather 'ego flattering'.

I know.....thats where ill be off to when im in need of a good print out to put on the for sale section. lol

edit: done the maths....im claiming about 32%....bless my heart eh!

You got 380rwhp on a rolling road, right? Not a hub dyno?

380rwhp = 500 flywheel if you allow 24% losses. That sounds fair enough to me mate.

It's the folks that allow 20%-25% losses for a hub dyno that are kidding themselves, IMO.

You got 380rwhp on a rolling road, right? Not a hub dyno?

 

380rwhp = 500 flywheel if you allow 24% losses. That sounds fair enough to me mate.

It's the folks that allow 20%-25% losses for a hub dyno that are kidding themselves, IMO.

Is the actual loss figure on a hub dyno a big can 'o' worms? I would have thought about 15%?

Sorry, but I'm not understanding the difference between a rolling road dyno result (at the wheels) and a hub dyno result (at the wheel hubs)...are they not measuring the same point of the power train ? Is there that much loss between the hubs and the tyre footprint ?

Yours, thick but curious.

Is the actual loss figure on a hub dyno a big can 'o' worms? I would have thought about 15%?

Well, using my car's results and 24% drivetrain losses as an example:

300 rwhp (measured at Surrey Rolling Road)

= 395 flywheel bhp allowing 24% drivetrain loss (24.0506329113924% if you want to be picky)

We can calculate that the

350.5 rhhp (measured at Thor)

= 395 flywheel allowing 11% drivetrain loss. (11.2658227848101%)

Sorry, but I'm not understanding the difference between a rolling road dyno result (at the wheels) and a hub dyno result (at the wheel hubs)...are they not measuring the same point of the power train ? Is there that much loss between the hubs and the tyre footprint ?

Yours, thick but curious.

Massive amounts matey. The tyre grip on the road isn't free, it's friction, and lots of it.

My dyno place used a transmission loss of about 7% for a manual. I was impressed.

-Ian

Sorry, but I'm not understanding the difference between a rolling road dyno result (at the wheels) and a hub dyno result (at the wheel hubs)...are they not measuring the same point of the power train ? Is there that much loss between the hubs and the tyre footprint ?

Yours, thick but curious.

At the end of the day, any dyno (RR or Hub) can be adjusted by the operator to give inaccurate and flattering results. Giving inflated power figures is good for business - people like good news.

The most powerful BPU cars made between 325 and 340 RWHP at Surrey Rolling road in one of the RR days

My car did 416 flywheel and 348 at wheels on a dyno dynamics in

bpu tune, dont know how accurate it was.

I was running 1.3 bar!.

Have a look at this thread:

http://www.mkivsupra.net/vbb/showthread.php?t=76414&highlight=midlands+rolling+road

Think these figures are about as accurate as you'll get on a RR dyno, there was 2 stock cars, 1 uk and 1 jap which both made just over 300bhp, a couple of bpu which made around 350 - 380 and mine which is really bpu+ made 418. The two cars with hybrids made 440-450bhp

Yep, on a dyno that shows 300bhp for a stock JSpec, expect to see 350-360max while at 1.2bar.

You can always add another 40-50% as 'losses', but it won't make the car any faster.

My BPU auto makes 300rwhp on a RR and 350.5rhhp on a hub dyno.

Yup, mine was 304rwhp on the RR - http://www.mkivsupra.net/vbb/showpost.php?p=1043482&postcount=88

Im BPU, with a mapped emanage will that eek out an extra 2 or 3 BHP or something? im still trying to work out the need for a mapped ECU with stock turbo's

Im BPU, with a mapped emanage will that eek out an extra 2 or 3 BHP or something? im still trying to work out the need for a mapped ECU with stock turbo's

Mine was overfuelling by a crazy amount (as they do) so I'd imagine another good 10bhp or more is possible through fuelling alterations.

you should see more with a mapped ECU of some sort mate.

When I had my old mr2 people with the same mods but without a mapped ECU were making 20bhp less than me.

Made 378lb/ft at 1 Bar on RR. Was just happy it was fueling well to be honest. A bit rich infact, as above, so would love to map.