TPI question

[tiger9297]

400+ hp questions

Have a '90 K5 w/ 256,000 miles on original engine. About to do a rebuild. I would like to get 400+ hp out of it. I have looked at the ZZ383 from GM performance parts. For my induction I would like to buy a TPI setup off an older Corvette/Camaro complete w/ wiring harness and computer. The computer on my '90 K5 controls everything, even the speedometer. If I buy this TPI package would that computer run everything on my truck???? Would I just use the computer that's on my truck now?? How would this work??

 

[Hossbaby50]

Your speedometer is actually driven by the Vehicle speed sensor not the computer. The VSS sends a reading to the computer, not the other way.

TPI is a great induction system. I really like my setup. TPI will not support a 400HP motor at high RPM's though without mods. It will run great and have lots of power in the low end and mid range but stock TPI runners are not great at flowing enough air to support a big motor at high RPM. You would probably start to flatline the motor in the area of 4000RPM with stock runners. Stock runners were good on stock or mild motors to around 4800RPM, and with a bigger motor that requires more are the RPM will drop some.

The low end and midrange will be awesome though. TPI really woke up my mild 350. The lowend and midrange was increased alot.

Port the plenum, add some aftermarket runners, an airfoil and or bigger throttle body and you can get the full potential of a 400hp motor.

Harley

 

[Ryan B.]

TPI rocks. The above mentioned is probably the cheapest route to try and achieve big numbers.. Ported plenum, aftermarket throttle body, big mouth intake manifold and big tube runners..
You might want to look into the accell superram... its a lingenfelter designed tpi setup for more tq and hp. a bit pricy but works well.. My friend runs that super ram on a 385 stroker.. UnTuned- put down 310rwhp 450rwtq & has gone 12.5 @ 108 in 3400lb '69 camaro.

 

[tiger9297]

So basically you are saying that I should not go with a TPI off an older Corvette/Camaro and go with a new unit?? That may be more pricey than I want to go. The Howell TBI setup will flow 750CFM and will support over 400 hp. It costs $1200. I can get an older TPI setup for about $500. I thought that if the older TPI setup would support as much hp it would save me $700. May not be able to go that route though. Suggestions?

 

[Hossbaby50]

If that Howell setup is a multiport fuel injection setup for $1200 then I would go that route, but I believe it is a TBI setup which won't get you all the benefits of a TPI setup.

You have a PM back.

The "newer" setups like a miniram or superram TPI is going to be much more expensive, probably in the neighborhood of $2000-3000+. I would run a stock system and see how you like it, and then add on some stuff to make it flow more air if you need too.

Harley

 

[tiger9297]

I made a mistake earlier by stating that the Howell system is a TBI. Actually it is a multiport system. The price is $1200. The reason why the price is lower than other multiport systems is, according to Howell, the system is set up to plug into my truck's existing computer and wiring harnesses so you don't have to purchase those items. The Edelbrock and other systems come w/ computer, harnesses and of course the system itself. The Howell system will flow 750CFM. Does anyone know what a TPI of an older Corvette/Camaro will flow??

 

[Hossbaby50]

If it is a multiport system for $1200 that isn't a bad price tag, but there are other factors that you have to ask them about. Since you want to run it on a high performance motor you stock computer chip will need to be changed out most likely since the motor specs are different then they are now. MAP systems (TBI is an MAP system) require a reading from the MAP sensor to tell the computer what is going on and make it run right.

Find out if the Howell system is a MAP or an MAF system. If it is a MAP system ask them how much chip burning is going to cost to get the motor to run right. It may take more then 1 chip to get it right.

You will also probably need to change your fuel pump to a TPI pump and make sure your sending fuel line is up to the 45 PSI that TPI fuel pumps put out. Also you need to find out exactly what Howell includes and excludes from the system. Are the sensors included or reused from your TBI setup, etc.....................

Harley