90 - K5 - 350 TBI - Turbo

[jack daniels esq]

Greetings Guys

Need some help before I head off to Asia

Be brutal

Thanks for a wealth of information & knowledge

BR>Jack

Truck Specs

1990 like new Truck - V8 – stock 350 190 HP – TBI - HEI – 24k miles – 700R4 – 40’’ Tires + Bling

Engine Build …. say additional 150-200 HP

2 x T3/T4 turbo
2 x wastegates
2 x 3’ intercoolers + 2 x fans
2 x K&N air filters + pipes + 1 x BOV
2 x TurboWerx Exa oil pumps – 1st feed both turbos, 2nd scavenge both
3qt turbo oil reservoir + filter + cooler + 1qt turbo puke can – below 2nd turbo + check valve, at 2nd pump
Total elevation say 18-24 inches above turbos, on firewall

MS II or III – for fuel mapping, EDIS spark, knock, timing, etc

Transmission 700R4 – fairly fresh - add B&M shiftkit + larger clutches – no donuts – sand dunes, rocks

Front mounted trans-cooler – before H2O radiator + fan + thermostat

Truck will live in Asia – ambient 35’C - cant even spell Chevy – maybe 4 row alloy H2O radiator

Q&A

What size injectors do I take – several suggestions please
Additional fuel pump size, brand
What size TBI resize/rebore
Is GM CPU up to turbo task – spark retard etc ?
EBay turbos – WTF …. all input appreciated …
more ....

 

[Russell]

The stock ECM probably will not handle the boost.

Might need to get an ECM from a Typhoon, Cyclone, Grand National or other factory turbocharged car / truck and modify the tune to run a V8 if you want a factory ECM.

TBI is not really a good platform for making big power being speed density. It fully depends on your capability to set the tuning correctly and does not have the engine protection protocols to cover your backside if you do it wrong.

Aftermarket EFI like a Megasquirt may be your best bet. If you are doing that you had midaswell just drop the TBI system and go with an aftermarket MPFI intake and injection system anyways. It will flow better, be easier to mate the turbo pot to and will have the programming options and engine protection protocols to make it run right and operate to it's highest potential without blowing up.

 

[82355]

Ditch your engine completely and install a Gen III.

Why two turbos?

Martin

 

[63chevyll]

I know accell used to make a map sensor that read vacuum and boost. Meaning...it gave a voltage reading up to 14psi.

The obviously the ecu needs to know what to do with the voltage (boost). But. The tbi ecus are very slow to compensate for quick fuel dekivery..needed for boosting a tbi engine

 

[jack daniels esq]

Ditch your engine completely and install a Gen III.

Why two turbos?

Martin

It must be my aircraft bias - redundancy works for me - easier to get home with a spare - especially in a foreign country - besides its almost easier to plumb the two turbos than just the one - I also have room for two hood- mounted inter-coolers with fresh air scoops on top, and fans below

Briefly considered an engine swap - might do that later - perhaps simply go with a 454 - no substitute for cubes

Has anyone ever bought a turbo off eBay - there is a $700 spread - can they be that bad ?

Thanks for the other additional info - will respond a little later

BR>Jack

 

[Cruz89K5]

Ditch your engine completely and install a Gen III.

Why two turbos?

Martin

This. I've got a Syclone, nightmare. Turbo LS- simple. Reliable.

I know accell used to make a map sensor that read vacuum and boost. Meaning...it gave a voltage reading up to 14psi.

The obviously the ecu needs to know what to do with the voltage (boost). But. The tbi ecus are very slow to compensate for quick fuel dekivery..needed for boosting a tbi engine

Turbo trans ams had a 3 bar map sensor, its what the aftermarket turbo GN/SyTy guys use.