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Rough MPG on a 600+BHP Supra?


Blackie

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So, If there was a big single turbo, say 500bhp engine, and you put a supercharger on to combat the massive turbo lag would it turn said 500bhp engine in to 550-600bhp or would it just get to boost quicker?

 

The money you'd need to twin charge it would make fuel economy inconsequential.

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:innocent:

 

Mine does high 20's off boost. When I give it some it drops to about 4 :(

 

a good example ! :D

 

a mid size turbo, take for instance a 67 can make full boost around 4-5k revs but you should see positive boost around 3000-3500 revs.

A gt35r on the other hand, setup properly should make positive boost as early as 2800 revs

 

im no expert but i think my numbers are almost right :)

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It's been that long since I've driven mine I can't remember when it spools :D

 

Are these questions feelers for what sort of turbo would suit your requirements if you went single?

 

I need to go turbo first or if theres a "cheap" single for sale that could be an option. its looking good for the very close future.

Edited by Blackie (see edit history)
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So when would it normally spool up? 3 1/2, 4k rpm?

 

If you are only aiming for 500-550 bhp you'd be looking at a T61 which will spool VERY early, much earlier than a TT. I think Wez's one used to make full boost by 3-3.5k in 2nd upwards :eyebrows:

 

There is virutally no lag on a turbo that size.

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If you are only aiming for 500-550 bhp you'd be looking at a T61 which will spool VERY early, much earlier than a TT. I think Wez's one used to make full boost by 3-3.5k in 2nd upwards :eyebrows:

 

There is virutally no lag on a turbo that size.

:yeahthat:

 

Or a GT35R, best to get a ride in some T61 sized cars and some T67 sized cars to see which suits you best

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One other thing to add is to not get confused between spool and lag, they are two seperate things.

 

In really basic terms:

 

Spool is how quickly the turbo will reach full boost THROUGH a gear

 

Lag is how quickly the turbo will go from idle to full boost once it is in the full spool area.

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I went in Fearlesses Chargespeed T78 single, that was quite vicious tbh

 

No disrespect to Fearless but that's probably not the best of singles to get a gauge of a single setup on. The T78 is an old truck turbo, from the dyno charts it's a slowish spooler, but doesn't suffer too much lag. It's one of those ones that will spool later in the rev range, but hit HARD, giving a sharper torque curve and therefore a great deal of acceleration during it's spool time (i..e as you say vicious). That's not to say it'll be a quicker car, a smaller more modern turbo will provide that kick much sooner in the rev range and have almost no lag.

 

As always, best to get a drive in as many cars as you can before you make your choice

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Too much for a little man like you to handle... :)

i will try my best ;)

No disrespect to Fearless but that's probably not the best of singles to get a gauge of a single setup on. The T78 is an old truck turbo, from the dyno charts it's a slowish spooler, but doesn't suffer too much lag. It's one of those ones that will spool later in the rev range, but hit HARD, giving a sharper torque curve and therefore a great deal of acceleration suring it's spool time.

 

Do you know what BHP it is? Its more phonominal acceleration i'm going to be looking for rather than top end, Hence the idea with the supercharger

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Do you know what BHP it is?

 

Nope, but I'd guess around 600bhp if it was running right at the time.

 

BHP is not a guide for turbo choice, torque curve is what you need to look at as that defines how it drives.

 

If you're not interested in top end and want something that's going to spool fast then look at a smaller turbo (T61 or T67dbb size) on a cast manifold.

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I'm running similar to what j above is but on a uk spec auto

around town I'm guessing 15ish mpg, booting it around 8-10

 

though I did do a 202 mile round trip to pick up an exhaust from LeeP's place on Sunday, full tank of fuel when I left and more than half when I got back :) that was with a mix of motorway, a-roads and 30-40-50mph b-roads. Was very chuffed with that so in theory I could get 400 miles out of a uk sized tank

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