Blown Turbo, Replace wit a Supercharger?

DanielSlack

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So, I had a friend borrow my 3000GT and when I got it a few day latter, while on the road, it began to run rough.

Then, while looking at the car for the rough running, fire sported out of the Rear Exhaust with very hot bits of metal.... parts of the metal look like it blasted from a turbo, maybe the rear turbo?

Still runs rough, but Turbo does not hold its compression, the meters are all dead.

I was thinking, instead of replacing the blown turbo, are there any good low profile superchargers?

I could increase the capacity of one turbo then switch over to a Super Charger?
 

obi_waynne

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You'd be doing a twincharge setup which actually works quite well on these as they already come with a twin turbo, I'd probably put the turbo in as the seconodary, then supercharger as the primary.


If you strip down the turbo you should see the problem and my guess is one of the sets of fins has broken off. Could be exhaust or intake side, probably on the exhaust side though.

Rotrex do some pretty compact superchargers, or go to the local breakers and find a mercedes compressor, it's much cheaper and you should find something suitable in there.

Mapping will need to be adjusted though, the supercharger makes power much sooner than the turbos would and fuel needs to be set accordingly.
 

TCJBOLDIE

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Err Waynne superchargers do not make power sooner than a properly matched turbo as the belt driven SC only produces max power and boost at the redline whereas a turbo can get to max boost pressure say 20psi at say 3000 revs and hold it all the way to the redline when belt driven SC will be only at app 1/2 of its max pressure app 10 psi at the same revs.
 

obi_waynne

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OOPS! I merely meant that superchargers do not experience lag like a turbo. They are very NASP in their power delivery (Linear) and as you say a turbo will deliver more power at higher up in the RPM range than they do low down (exponential increase).

Once again I should have been clearer! Sorry!

The fuel map for a supercharger is different to that of a turbo, so it's not a straight swap without doing some mapping, unless you happen to be extremely lucky in your application.
 

DanielSlack

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OOPS! I merely meant that superchargers do not experience lag like a turbo. They are very NASP in their power delivery (Linear) and as you say a turbo will deliver more power at higher up in the RPM range than they do low down (exponential increase).

Once again I should have been clearer! Sorry!

The fuel map for a supercharger is different to that of a turbo, so it's not a straight swap without doing some mapping, unless you happen to be extremely lucky in your application.

Thanks for the information. Now my car has twin turbo, I originally was thinking of staggering the two turbos, just making the rear turbo a bit larger so it might last longer, but I could add a supercharger with the twin turbo and adding a water meth injection, what are you thoughts on a setup like that?

Too redundant?
A potential to be too problematic?
 

obi_waynne

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Bear in mind that when you compound compress the air you get much more pressure.

2psi turbo + 1psi turbo or 1psi supercharger could end up with 5-6psi of charge, this is a problem for fuelling and can strain the engine.

Personally I'd get the max psi as soon as I can and work on building a flat torque band that is quite wide. Small turbos work best at low rpms, big turbos at high rpms, you can switch between them or stage them accordingly.

The larger turbo is a good idea, have you looked into twin scroll turbos, they seem to be where people are heading nowadays with turbos, and you might get away with just one well designed twin scroll and save some weight.

Water Meth is a pain IMO and complicated to setup, on a road car i'd steer clear, on a track car when you can pit the car and tweak and check regularly there are gains to be had.
 

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