Let's talk turbos!

[Samurai 20V]

You are effectively spending a lot of money to get a tiny bit less lag. A single turbo capable of a genuine 700 BHP will be laggy, it will kill auto boxes, and be terrible off the line. Unless you just want pub talk figures, (and in that case you should have kept the glamorous twins) aiming for a genuine 500 BHP with as small a turbo as will manage it will give SO MUCH more real world, on the road performance as to be incomparable. A good driver in a single turbo MKIV built for a max of 500 BHP will leave a good driver in an identical one making 700 BHP for dead on average roads.

 

A 500 BHP engine will still kill auto boxes, just not as frequently.

 

Forget hi-stall torque converters, useless and an embarrassment in a road car. Strictly drag race only. STRICTLY!!

 

 

Add in the fact it's an automatic and the situation is even worse. If you don't look for maximum area under the torque curve you will never make a road car automatic turbo go well, unless it's something like a seven speed box.

 

Forget the red line figures, look at the torque figures, you don't want a road car that needs running up towards the red line to give torque and power. Firstly it attracts the wrong sort of attention, a copper hearing a loud engine at 6K RPM is a hair trigger away from investigating, pointing a radar gun, or selecting 1st gear and turning on the blue lights.

 

Secondly, an old school straight six 3 litre, run hard at high RPM's will need constant maintenance. Same engine making big torque at lower RPM's is a LOT less stressed.

 

Sending a turbo to Owen Developments for a rebuild / repair or a housing / impeller swap, is a LOT less hassle and cost than sending it to the USA.

 

Garrett have forgotten more than Precision will probably ever know, they are a major player, their research and development is second to none.

 

Hi Chris..

 

Where would you rate a 450hp stock twined car is this comparison?

 

Off course assuming its a healthy car and not one wheezing its way with 20year old ceramics..

 

Sorry for the hijack.

[Chris Bailey]

Would be nice to see the spool / dyno over lay on them

 

I have an old T67 dbb with a .68 turbine housing and make 1.2by 4000 in first /second when I can get traction, turbine housing makes the most spool difference im sure .

 

I know Jamies car made full boost in 6th gear at 2800rpm. That's with a 1.00 A/R divided I think.

[JackyBoi]

You are effectively spending a lot of money to get a tiny bit less lag. A single turbo capable of a genuine 700 BHP will be laggy, it will kill auto boxes, and be terrible off the line. Unless you just want pub talk figures, (and in that case you should have kept the glamorous twins) aiming for a genuine 500 BHP with as small a turbo as will manage it will give SO MUCH more real world, on the road performance as to be incomparable. A good driver in a single turbo MKIV built for a max of 500 BHP will leave a good driver in an identical one making 700 BHP for dead on average roads.

 

A 500 BHP engine will still kill auto boxes, just not as frequently.

 

Forget hi-stall torque converters, useless and an embarrassment in a road car. Strictly drag race only. STRICTLY!!

 

 

Add in the fact it's an automatic and the situation is even worse. If you don't look for maximum area under the torque curve you will never make a road car automatic turbo go well, unless it's something like a seven speed box.

 

Forget the red line figures, look at the torque figures, you don't want a road car that needs running up towards the red line to give torque and power. Firstly it attracts the wrong sort of attention, a copper hearing a loud engine at 6K RPM is a hair trigger away from investigating, pointing a radar gun, or selecting 1st gear and turning on the blue lights.

 

Secondly, an old school straight six 3 litre, run hard at high RPM's will need constant maintenance. Same engine making big torque at lower RPM's is a LOT less stressed.

 

Sending a turbo to Owen Developments for a rebuild / repair or a housing / impeller swap, is a LOT less hassle and cost than sending it to the USA.

 

Garrett have forgotten more than Precision will probably ever know, they are a major player, their research and development is second to none.

 

Thanks for the help Chris. Fortunately I have a v160 so don't need to worry about destroying it yet at the moment to keep the car in it's power band you have to keep it above 5000rpm otherwise you'll be waiting for the boost, which is fine in a straight line but down twisty roads it can be tricky, and as you said it kills the engine keeping it at high rpm, especially as it's stock. I'm just wanting something a bit more street-usable, since this is a 100% road car. Since American's are so into their drag racing, I'm hoping I won't have trouble selling the kit over there.

[Hemanhead]

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