What's wrong with tuned port?

[smitty62]

I see TPI units being sold for what seems to me to be dirt cheap. I've always thought this would be neat on my truck, but now I'm getting a little nervous. Is there something wrong with putting one of these units on my 350? I know I would have to buy a modified/new wiring harness and install an electric fuel pump---what other major expense would I have?

[lock]

Nothing at all wrong with a TPI. Awesome setups. Prices probably coming down as more and more thirdgen f-body's bite the dust and get parted. Plus there are other great setups to use now such as the LT1 and LS1. I love the look of a nicely polished TPI. Those long tubes look sweet.

[jorgensensc]

I am also thinking of doing this swap very soon. Hopefully all funds can get put in the appropriate places soon enough for me to do this swap and an overdrive tranny. Don't forget you also need the correct dizzy too. It is often forgotten.
Shawn

[chassispro]

Nothing is wrong with tune port. It seems as though now everyone is using the LS1 and LT1 because you can usually find a fairly low mileage running motor, so they just go with that. I actually have a TPI setup I'm going to be installing on the 406 I'm going to put in my truck over the winter. Oh yeah, it's gonna have twin turbo on it as well.

[smitty62]

Chassipro---how are you going to get it to hook up?

[Shane65]

Chassispro, I would really check out the tpi choice for your 406. They can't flow enough air for a larger engine. They were adequate for 305 and 350 stock engines but are very limited to any engine that has modifications that will mean the engine needs more air. Ask around before you go too far.

[neonlarry]

There are lots of twin turbo tpi cars around. Yes, there are better ways to do it (look at some of the stage 2 turbo buicks)or some of the cars on here http://www.sdsefi.com/project.html Using the tpi manifold should work fine though.

[72C203503ONTHETREE]

TPI is fine for low power or for towing since they are designed for low rpm power and throttle response. You can get aftermarket runners that will make more power than the small stock runners. You will also have to have the computer(make sure you get that and for whatever trans you plan on using) reprogrammed if you plan on using a different cam or other air flow mods. Don't bother with the Hypertech Power programmer or similar, get the computer properly set up for your set up. The stock TPI 305 and 350 kind of die out after 4,500 rpm or so, the runners are too long and small to make much top end power. Save up some money and get the Accel, Holley, or other full aftermarket system, it looks like TPI but comes with programmable computer you tune yourself and are set up for power over mileage, even though they do get good mileage.

[Shane]

The only thing I can see wrong with a TPI setup is that I don't have one.

[Mudder]

I want one!!!!!!!!

[Bowtie67]

The TPI is really a nice setup, There are guys turning in some good numbers using these systems. There are some drawbacks, the 4500rpm limit was more due to the cam issue than the limitation of the system, the TPI will go to 5200rpm, there are aftermarket baseplates and runners from Edelbrock and a different top peice from Accel to bring these up to higher RPMS. But for a fairly stock to a slightly modified engine setup, daily driver there really isnt much of a better setup than these. They really produce good torque and fuel economy. The reason for seeing the price drop on these is because of the new engines cant use these setups and they made how many of the TPI's over the years. Here is another company that builds a very simular system based on the TPI setup with a little better prformance and a bit better price than buying a whole new system setup from Edelbrock, Accel, and Holley.

http://www.firstinjections.com/products.htm

[chassispro]

Smitty62 : I'm going to use one of the aftermarket DFI (digital fuel injection) units. But if I were going to leave it stock I'd just use a painless wiring harness. You can get a painless harness for around $300 for the TPI setup.

Shane65 : The TPI setup I have is the aftermarket Accell unit. it has been ported and will flow enough air for what I'm gonna use it for. Besides, it's not a race truck, It's just going to be a play toy. The TPI and turbos are really just going on for the "ooh, ahh" factor.

[Shane65]

Here's what I run on my Chevy II for "ooh, aah's".

[chassispro]

That's pretty cool. Looks like it has been converted From mechanical fuel injection to EFI. What brand EFI you run on it?

[69 Short Fleet]

NeonLarry, WICKED link, thanks for sharing!

[Shane65]

I converted everything myself and use an Accel DFI computer and wiring harness. Been running excellent since 1999. This pic is from last year, when I changed the colour of the engine.

[gabet40]

good advise from 72c203tree. i had an accel dfi multipoint system but couldnt find the equipment to tune it cuz it was so outdated. so i purchased a brand new holley commander 950 conversion kit and totally simplified for windows instead of DOS. here the latest pic of mine, still plenty of work tho til i can turn her over. multipoint and tpi systems compute their injection based on all the same sensors, but just have different air flow pattern and point of injection

[red71cheyenne]

I really like the TPI, if nothing else, just for the looks. The throttle response is great, the "ooh, ahh" is great and its a relatively easy conversion. The one thing I don't like about mine, is that I don't get great fuel mileage. On the highway I still only get about 14 and I got that running a holley 600. If I could get upwards of 20, I would be really happy about it. If anyone knows how to improve my fuel mileage, I'd love to hear about it. Jeff.

[gabet40]

redcheyenne what ECU are u runnin? GM? cuz the aftermarket ones u can program for ur specific application and get a few more miles out of em

[red71cheyenne]

Mine is a GM ECM, with a custom Prom. Its setup for my engine and the whole deal. I even added a speed sensor, but no luck getting better mileage. I am going to drop down to 19lb injectors soon and see if that does anything.

[gabet40]

ya that should def cut the milage down but ur also gonna have to reconfigure the ECM again. itll also cut down on ur horsepower but nothin beats gas $$$$ saved

[red71cheyenne]

Ya, I'll just have the guy burn me a new prom for it. I'm waiting to get the injectors put back in til I get the plenum and runners polished though, so no rush. Jeff.

[Shane65]

Here's a formula for injector sizing. Also has a chart based on engine horsepower.

http://westers_garage.eidnet.org/tec...info.htm#cat11

[Custom 68]

I have just finished my install however it is only on the Chassis right now the body is sitting by it ready for paint before I stick it back together. They do look cool and I hope to get some good power out of it. Mine is a 327.
Dave

[red71cheyenne]

Thanks Shane! Custom, where are the pics!! Jeff