tpi vs tbi

[bonez]

my 82 z-28 currently has a 306 tbi in it..i am wanting to pull it and drop either a 350 or 383 in..question is should i go with tbi or tpi? or convert to an ls1 or ls2? looking for something dependable with as less amount or engine problems/maintance as posible,,,not used for racing just a something for the car shows are cruising on the weekends,,thanx

[nemocamaro]

if the question is tpi or tbi, tpi ftw.

if you can upgrade to a lsx, just do that.

[nighthawk15]

If you were going to go with a gen 1 motor I would use a carb on it, but if you want to stay with injection an LSx of some kind, or even an LT1 would be a better route to go IMO. TPI is better than TBI, but the stock intake manifolds still choke out a lot of the top end.

[Etown_RS]

TBI has it's advantages over TPI (top end flow, expense of parts), but I would probably upgrade to some sort of LT1 based injection over either.

[egott_91]

TPI over TBI anyday.

But like stated before, if you can do and LSX or LTX swap...do that instead!

[Giovannetti]

TPI has more power. TBI is a little cheaper. Ls1 has more pwoer and you can get more power per dollar out of it then an LT1 but a complete LT1 set up is prolly cheaper then a LSX set up

I personally have no issues with driving a TBI set up if it is ONLY a show car or cruiser. Now for racing you couldnt pay me to race a t bi set up even though they do make TBI upgrades on the intake

[Etown_RS]

There is quiet a bit of recent aftermarket support for TBI. They make a TBI-to-Vortec adapter intake (so you can run Vortec heads), a computer conversion that allows you to operate a tune on the fly computer with full time datalogging. Plus, you can use any intake for SBC with a TBI adapter. I think the most you can flow with a 454 TBI is ~750-800 CFM. If I were going to stay with 3rd gen injection, I would probably go with TBI since I already have TBI. But that's just me.
There is one thing to be said about TBI motors...if maintained, they go forever. I've seen em with 300-400k miles on em. I actually want to build a nice TBI 350 and DYI tune it just to see if I can do it. Just not very soon and not in this car.

[kcougar]

hmmm please revive this topic, im looking at a 91 z28 with a 5.7 tpi id like to hear more about the opinions.

[egott_91]

Originally Posted by kcougar

hmmm please revive this topic, im looking at a 91 z28 with a 5.7 tpi id like to hear more about the opinions.

I would jump all over that. You don't see too many 5.7 TPI in 91-92. At least, not around here! I have a 91 Zee w/ a 305 TPI and it makes good power for being a 305. I'd love to ride in a 350 Z from 91 just to see the difference.

[rolling thunder]

I think the biggest +1 for TPI over TBI is just the simple concept of how it works. One one hand you have the TBI wich is basically and electronic carberator. It give one nice heavy shot of fuel for all the cylinders to enjoy (and fight over). TPI on the other hand has a fuel injector for each cylinder. Problem with TBI is first that means that individual cylinder tuneing is not possable. And just the fact that all the cylinders are competeing for the same shot of fuel means there is the possability for an uneven distribution of fuel to differen cylinders. Not really a huge deal if you just want the car to run but performance is not really desireable. Second lets say you snap the pedal down the soonest the motor can react to this is the next cycle as thats the next time the fuel injector fires. With TPI it can react as soon as the next cylinder needs fuel. This makes TPI have better throttle responce. Finally fuel atomization is better with TPI just for the sheer fact its sprayed pretty much at the intake valve where as TBI fuel hast to travel through the intake manifold to get to the cylinders. All of theres issues arnt really such a huge deal but do give TPI a bit of an advantage. TBI was more of an economical way to produce a reliable fuel injection system where as TPI is more of a performance orented design. Eather one will work just fine theres advantages to both but i would say in my oppinion if i couldnt afford to get an ls1 or a lt1 i would take a TPI motor over TBI set up anyday.

[Giovannetti]

well now that i look back in time my car originally a 350 tpi and had some grunt. I could run with the stock Lt1's with autos and could pull a 14.1 at the track. I also could get a RWHP of 245 and i realized that TPI isnt easily upgradable. Yes the motor is to a point and all but sheesh the intake gets expensive. Now the motor i have now isnt tpi anymore and i went carb'ed and i am FULLY happy especially tuning a carb is as easy as turning a screw.

Now saying all that i decided to get me another 3rd gen but im going the 305 TBI route b/c once the motor goes i can easily swap out the 305 with a built up v8 Now the 350 TPI is costly b/c there arent too many in good c onditions but the 305 TBI is ALOT cheaper b/c it is what it is ya know

[kcougar]

well, the guy wants 1500 for it, its maroon no accidents, and a 350 tpi. any ideas on it being a good deal? also, i thought that it would have disks in the back but it dosnt, could you get a 91 z with out disks?

[rolling thunder]

Well assumeing its in good condition ide say thats a good price for the car. Disk brakes in the rear were optional and personally i havnt seen to many of them kinda far and few between deal.

[Etown_RS]

Yea, rear disks were a option. I'd get it for that money.

[egott_91]

You could get disks in the rear. Usually you only saw disks on the 1LE cars though. My 91 Z has drums in the rear...