[Mk2] [Turbo] big power for internally gated turbo

[Quibble]

Just stumbled across this on another website and I was surprised at the power the turbo was able to make. I thought you had to go for an external waste gate if you wanted that sort of power. I also always wondered what was the better engine, the Cosworth or the 3SGTE. Any thoughts?
http://www.turbosport.co.uk/showthread.php?t=479059

[MR2 Rich]

I think the YB Cossie engine and the 3SGTE are pretty much equal. Both brilliant engines that can be tuned to massive power. They both have their weaknesses. The 3S with the Rev3 casting issues and the Rev1+2 heads not being as good as the Rev3. The YB 2wd had issues with overheating and head gaskets blowing due to smaller water jackets. The Eggenberger touring cars had an extremely strong block that no one else had, mated with a 4x4 head would be an awesome combination. Likewise a Rev3 3S engine that has been check for thickness is an awesome engine.

[Quibble]

I get the feeling the Cosworth costs more to tune.

[shinny]

Wastegates have nothing to do with power... the advantage of an external wastegate is in packaging, not in power.

[bobhatton]

I think the YB Cossie engine and the 3SGTE are pretty much equal. Both brilliant engines that can be tuned to massive power. They both have their weaknesses. The 3S with the Rev3 casting issues and the Rev1+2 heads not being as good as the Rev3. The YB 2wd had issues with overheating and head gaskets blowing due to smaller water jackets. The Eggenberger touring cars had an extremely strong block that no one else had, mated with a 4x4 head would be an awesome combination. Likewise a Rev3 3S engine that has been check for thickness is an awesome engine.

I supplied Eggenberger with lots of parts back in the 1970s/80s

The Rev1/2 heads flow much more air than the Rev3 heads but the Rev3 exhaust ports are better.

The big problem with the Cosworth was lifting the heads, they had to be bolted right the way through the block to keep them on

[Marf]

Wastegates have nothing to do with power... the advantage of an external wastegate is in packaging, not in power.

Usually the biggest advantage of an EWG over an IWG is flow. EWG can flow more than IWG, normally.

Just stumbled across this on another website and I was surprised at the power the turbo was able to make. I thought you had to go for an external waste gate if you wanted that sort of power. I also always wondered what was the better engine, the Cosworth or the 3SGTE. Any thoughts?
http://www.turbosport.co.uk/showthread.php?t=479059

Borgwarner EFR turbos (as in the car on your link) seem to do just fine with an IWG

This is from an RX7 with a BW EFR IWG - up until this point pretty much every big HP RX7 build was EWG



Might have something to do with the physical attributes of the IWG

[shinny]

Wastegates have nothing to do with power... the advantage of an external wastegate is in packaging, not in power.

Usually the biggest advantage of an EWG over an IWG is flow. EWG can flow more than IWG, normally.

Yup... that's just the other side of the same coin

An EWG flows better because it's generally bigger... and that's because it's tricky (or even impossible) to package a big enough IWG in a turbine housing. If you could get a big enough hole for the IWG then there wouldn't be much advantage (gas flow post-turbine is better with an EWG that's divorced for a couple of feet or just dumped to atmo).

Still, it's got very little to do with power, bar minor gas flow effects.

[MR2 Rich]

I think the YB Cossie engine and the 3SGTE are pretty much equal. Both brilliant engines that can be tuned to massive power. They both have their weaknesses. The 3S with the Rev3 casting issues and the Rev1+2 heads not being as good as the Rev3. The YB 2wd had issues with overheating and head gaskets blowing due to smaller water jackets. The Eggenberger touring cars had an extremely strong block that no one else had, mated with a 4x4 head would be an awesome combination. Likewise a Rev3 3S engine that has been check for thickness is an awesome engine.

I supplied Eggenberger with lots of parts back in the 1970s/80s

The Rev1/2 heads flow much more air than the Rev3 heads but the Rev3 exhaust ports are better.

The big problem with the Cosworth was lifting the heads, they had to be bolted right the way through the block to keep them on

Interesting to hear. Did you supply anything for the FOMOCO Texaco sponsored Rs500's? Many owners long stud them to prevent the head lifting but they also have problems overheating and blowing head gaskets. As I'm sure you will know?