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The mkiv Supra Owners Club

Single Turbo Debate = BHP


Jurgen-Jm-Imports
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I've gone for a BL t61 as I want good usable power, i'd rather have around 400 - 450 rear wheel bhp than something with 700 rear wheel bhp and struggle getting the power down, there's no point in having it if you cant use it. From what i've seen a good t61, t67 (or something similar), will be on boost and gone before a big turbo like a t88 gets going. A t88 would be pointless around my way.

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its going a bit off topic here but the thread is why do most single turbos read less bhp comapared to ones from japan.

 

is it due to turbo choice

badly built singles

bad mapping

Budgets

etc

etc

etc

 

 

am just curious to know, but it looks like the turbo choice and budget been the main issue

 

 

Yes, yes, probably yes, and probably yes.

 

I should imagine the Jap ones have poor turbo choice, are badly built without enough thought to longevity and drivability, are probably mapped to run as lean as humanly possible and it's most likely all down to the lack of budget. ;)

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Guest Nicholas

I think the lack of power is down to the stock cams? I have a stock engine and my single makes 537BHP @ Fly as Dan Turner say's the stock cams are very restrictive when it comes to raw HP.

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I think the lack of power is down to the stock cams? I have a stock engine and my single makes 537BHP @ Fly as Dan Turner say's the stock cams are very restrictive when it comes to raw HP.

 

Cams cannot make up thousands of rpm of loss in spool time. They make a difference yes, but it's more fine tuning than marked differences to the turbo spool time.

 

See the data logs Ian C posted last year for exact details on the difference. I think it got an extra 50bhp or so at peak.

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Guest Nicholas
Cams cannot make up thousands of rpm of loss in spool time. They make a difference yes, but it's more fine tuning than marked differences to the turbo spool time.

 

See the data logs Ian C posted last year for exact details on the difference. I think it got an extra 50bhp or so at peak.

 

Ahh I see, will take a look at Ian C's posting.

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I always thought changing from stock cams to say 256/264/272 cams increased the lag a little.But offers more power higher up the rev range.

 

I think Ian found a 264/264 setup raised both the mid range and high range torque (obviously with map changes).

 

His test on the 272/264 setup showed a massive decrease in mid range torque and spool time.

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to compare turbo to turbo ,or car to car by using BHP is pointless the maximum bhp is only a function of RPM AND TORQUE

it does not indicate how fast a car is

could a 350 bhp car be faster than a 400 bhp car -YES for example if the 350 was a diesel

1.4 turbo race cars were making way over 1000 bhp -how? they were revving to 18000 rpm!!!! but you wouldnt want to drive one to the shops or in a traffic jam!

we should ban bhp and make everyone use torque and redline

ie my car makes xxx torque and redlines at yyyy rpm

a bit off topic but who is running the highest torque on the forum?

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Strictly speaking even that doesn't give a true indication of how quick a car is.

It's all about area under the torque curve. ;)

You could have a really peaky 500lbft at 6500rpm that readlines at 9000rpm that would be slower than a car that has a flat torque curve that reaches 400lbft at 4500rpm and redlines at 7000rpm.

I'll stop being pedantic now. :)

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Cams cannot make up thousands of rpm of loss in spool time. They make a difference yes, but it's more fine tuning than marked differences to the turbo spool time.

 

See the data logs Ian C posted last year for exact details on the difference. I think it got an extra 50bhp or so at peak.

 

Usually cams will aid in spool up because it makes the head flow better. More flow = better spool. There was a dynosheet posted on supraforums that was taken before and after HKS 264 cams and it made better power across the power band. This was with a T61 or T67 turbo.

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Usually cams will aid in spool up because it makes the head flow better. More flow = better spool. There was a dynosheet posted on supraforums that was taken before and after HKS 264 cams and it made better power across the power band. This was with a T61 or T67 turbo.

 

I agree, the 264/264 setup offered increase in spool after the map was modified, I am still waiting for my 264 inlet cam :(

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