What BHP figure do you think I should have?

[paulmacvxr8]

Evening all,

I'm after a few opinions on what FWHP you think I should have.

Had the car on a rolling road today and the figures I got were shocking.

The car is a VXR8, 6.0, LS2 manual and has covered 44k miles.

Mods so far are Walkinshaw Supercar exhaust, Walkinshaw headers and 200CPI cats, X-pipe to replace centre silencer. Walkinshaw Camshaft, VCM OTR CAI and 10mm Magnecor leads, car mapped by Walkinshaws when camshaft installed however no additional mapping has been done since the headers and cats were fitted.

I know that RR figures are never that accurate but I'm just wondering if the RR is junk or if my car has a problem.

I hope those with similar setups wouldn't mind sharing their opinions.

Many Thanks
Paul

Edited by paulmacvxr8 on Sunday 30th November 19:05

[Gary H 2008]

"and the figures I got were shocking."

Please define shocking. Does it drive in a shocking manner? Has the performance deteriorated since you had the work done? What are you using as the comparative?

Cheers

[fastbikes76]

Where was it run and what make of Dyno ?

[paulmacvxr8]

The figures were,

Run 1 was 425 bhp (Flywheel)
Run 2 was 389 bhp (Flywheel)

The car drives no different, I can't compare it to any other VXR8 as it's the only one that I've driven.

Paul

[r8black]

Noted mods would expect no less than 400

[paulmacvxr8]

It was run @ AMD in Essex.

I'm unsure what make their Dyno is.

[r8black]

paulmacvxr8 said:

It was run @ AMD in Essex.

I'm unsure what make their Dyno is.

They know my r8 there have run it twice there

Is your Car red by any chance

[paulmacvxr8]

r8black said:

They know my r8 there have run it twice there

Is your Car red by any chance

Yes mate it is.

They appeared to know nothing about R8's in my opinion, they struggled to find a way to strap it down.

I've been told the low figures could be because it was losing traction on the rollers.

Going to run it on another dyno in the next week or so.

[jonnM]

paulmacvxr8 said:

The figures were,

Run 1 was 425 bhp (Flywheel)
Run 2 was 389 bhp (Flywheel)

The car drives no different, I can't compare it to any other VXR8 as it's the only one that I've driven.

Paul

Given the mods you've listed, I'd say they were RWHP figures??

[r8black]

paulmacvxr8 said:

r8black said:

They know my r8 there have run it twice there

Is your Car red by any chance

Yes mate it is.

They appeared to know nothing about R8's in my opinion, they struggled to find a way to strap it down.

I've been told the low figures could be because it was losing traction on the rollers.

Going to run it on another dyno in the next week or so.

Are you local to the AMD area if so we can compare cars, did AMD stick three heavy chaps in the boot to stop it spinning

[paulmacvxr8]

Definitely flywheel figures, I double checked with them.

I'm about 70 miles away from AMD, I live in Slough.

No one else was in the car apart from the RR operator.

[badboyburt]

Paul the RR Graph is shown in HP not BHP mate, dale just pointed it out on that RR Thread.

Now sure how to recalculate it, anyone good with formulas ?

[jameshsv]

paulmacvxr8 said:

Definitely flywheel figures, I double checked with them.

I'm about 70 miles away from AMD, I live in Slough.

No one else was in the car apart from the RR operator.

Why dont you go too surrey rolling road its the one most of us use to get figures.I also think those are rwhp numbers and not fwhp.

[paulmacvxr8]

badboyburt said:

Paul the RR Graph is shown in HP not BHP mate, dale just pointed it out on that RR Thread.

Now sure how to recalculate it, anyone good with formulas ?

I'll have a look Bri, never heard of that before to be honest.

[ARAF]

You should have saved yourself the journey, and visited Vixpy at Surrey Rolling Road, Farnborough Hampshire. He has lots of readouts for big V8s, so is probably worth checking with.

BTW, rolling roads cause more grief than anything else. They do pick up the odd engine with problems, but most of the time the results are just disappointing.

Depending on your cam, and how clean your air filter is, I would expect you to have around 400hp at the wheels, and 500bhp at the flywheel.

[paulmacvxr8]

jameshsv said:

Why dont you go too surrey rolling road its the one most of us use to get figures.I also think those are rwhp numbers and not fwhp.

Have heard good things about Surrey Rolling Road, might try and arrange a session with them then.

I promise their figure are flywheel, I asked as was quite shocked when they gave me the results.

[badboyburt]

paulmacvxr8 said:

I'll have a look Bri, never heard of that before to be honest.

me neither, hence why i swerve AMD but love the free bacon rolls lol

[paulmacvxr8]

badboyburt said:

me neither, hence why i swerve AMD but love the free bacon rolls lol

I had such an enormous breakfast that I never bothered with the BBQ.

[ARAF]

badboyburt said:

Paul the RR Graph is shown in HP not BHP mate, dale just pointed it out on that RR Thread.

Now sure how to recalculate it, anyone good with formulas ?

About 20% loss has been mentioned here before, which would mean the quoted figures + 25%

That doesn't explain the wild difference in figures - but then that's dynos for you.

[badboyburt]

ARAF said:

About 20% loss has been mentioned here before, which would mean the quoted figures + 25%

That doesn't explain the wild difference in figures - but then that's dynos for you.

cheers ian, Dynos eh lol