Why all the negative attitude over on the TPI board? Things like TPI should have been a "truck" intake...TPI should have never been put into a "performance" car...TPI should be replaced with a "carb" if you want faster performance. Well, maybe not literally word for word, but that's the overall sense I get when I'm in there. I've never seen so much negative talk about an induction system on an enthusiast web site ever.

Shouldn't the TPI board be "pro-TPI" instead of "get something else" if you want to be fast board? The TPI board is getting to be what the V6 board use to be or maybe still is. I don't know about you, but TPI does has some advantages. First of all, it's hands down the best looking intake designed in an automotive application. The aluminum fuel rails have a styled "ribbed" extruded appearance to them and the fuel tubes themselves have a custom light-beige metal-flake powdercoating finish on them as well. A lot of "detail" was designed into these parts. Secondly, TPI has low RPM torque and lots of it. It feels like a rocketship compared to the short runner LT1 and even the highly praised LS1. At least around town at low RPMs that is. Thirdly, it was the first modern fuel-injection setup for GM. It finally gave the old SBC a "state-of-the-art" induction system. Historically speaking, TPI gave the corporate "305" a new lease on life in the second performance revival of the mid '80's.

For me, it seems like the same people who criticize TPI the most are the same ones who want to put 4th gen consoles, doorpanels and dashboards into their 3rd gens. Not specifically, but in a general sense. Jeez, why don't they just all buy 4th gens instead and leave the 3rd gens to people who really appreciate them?

 

I think most of those negative people on the tpi are mainly ignorant. They don't understand the dynamics of tuned intake and exhaust systems, so they don't have a clue how to make it work. If you don't have to pass a visual smog test, any idiot can bolt on a carb and get performance. There are people on this board who have proven that tpi can make performance. If you are building a race car, the tpi can be modified to move the power band up the rpm range and give it more top end. I think for the street, for someone who wants good acceleration off the line, but doesn't street race or drag race on test & tune days, the tpi is probably as close to the perfect induction system as you can find.

 

Is it me or are all the stock induction systems criticized? CFI, TBI, TPI.

 

Everyone thinks what is on their car is the best thing since sliced bread.

 

yea, i have been wondering the same thing. i think it is crap all the flak that TPI gets. out of the 5 F-Bodies i have had, 2 were TPI and those were two of the fastest out of the box i had ever driven. the only faster one was my 455 Poncho powered 82 Trans Am...

Josh

 

Yep, MPFI is the snitchz! Its hard to beat wanting one of these babies. Actually, that and my intake port angles are my battle.

 

:hail: Any pictures of that?!

 

Mmmhmm, gotta love MPFI....

 

Either that or whatever latest and greatest thing they are getting ready to spend more $$$$ on.

 

each intake design has its pro's and con's. Some people want to rev their engines and make power up there and TPI was never intended to do that. It was designed to create torque at lower RPMs so you wouldn't need to rev the engine. Some intakes provide a flatter torque curve and other's are designed to be used with large airflow requirements.

 

What about the intake you are planning to run, where does it make its horsepower?

Uhh, I mean good point James.

 

The TPI was originally designed specifically for the 305's bore and stroke and power characteristics. When you compare it with what else was available circa '85, it is an excellent system, and delivers very usable power in a very attractive package. The 305 would have never top-ended a 302 Ford in stock form no matter what intake was on it.

On a 350, it is a bit of a mismatch, and as you modify for more power you need to spin the motor more, and the TPI was not designed for high airflow or higher rpms. The TPI system does what GM originally designed it to do. If you want it to do something else, you either need to modify it or change to something else. Whining doesn't create horsepower. Never did.

Troy
So Cal

 

i would much rather have a tpi sep up than a tbi set up if it were up to me but hey what you gonna do right ...lol

 

i have pics SOMEWHERE, i will have to locate them, and no promises i can do that. when i moved up to Washington from Alabama i don't know if they made it with me. they might still me in Alabama. it was a straight line ROCKET, but wasn't worth a flip in the curves...

Josh

 

LT1/miniram intakes generally provide a flatter torque curve over a broader RPM range whereas the TPI intakes provide a peaky torque curve at a lower RPM. If I was to run a LT1/miniram intake it would most likely HP peak around 6200-6300 RPM.

 

Interesting...
The stealth ram I'll be using makes its power around that neighborhood. It will allow me to take advantage of that custom solid roller im going to run.

 

The TPI was originally designed for the 305? That sounds strange to me since in 1985 it also appeared on the Corvette.

I would think it was desiged for the 350 since the Corvette is the flag ship and the F-body typically got detuned Corvette goodies.

"The first production TUNED PORT INJECTION (TPI) appeared on General Motors vehicles in 1985. The GM vehicles built with these systems were Corvette, Pontiac Firebird & Trans AM, and the Chevrolet Camaro. These systems according to the manufacturer rendered up to 30 % improvement in Horsepower, torque and economy over carbureted systems, Independent labratories conducted numerous test on the TPI systems and indicated these claims were conservative and that increases of up to 35% in these three areas are attainable.

The 350/5.7L engines from the factory went from 205 HP (1984 Corvette/ crossfire injection) to 245 HP with the addition of TPI. The only differences were the addition of the TPI (1985) and improvements in the valve train (1987). Note that this is a 20% improvement over another proven form of fuel injection."

 

Bret,

The 305cid SBC was originally intended to be used in the new C4 Corvette when it was being developed in the late '70's. I'm not sure what events lead up to the decision to eventually use the bigger 350cid block, but fortunately GM decided to go with the 350 instead of the 305. The "305" based TPI fuel-injection system was already completed so they had to use that on the 350cid block as well. Considering this fact, the decision to go with the 350 must have been rather late in the C4 powertrain program.

TA is correct. The LTR TPI setup was specifically designed for the 305 SBC. It gave the "305" 275/285ft lbs of TQ compared to the 245 of the L69. It also increased HP to 215 from 190 (L69). MPG and drivability was much improved as well. Of course, later years would see 300ft lbs and 230hp levels with the G92 option on 5spds. I believe the L69 was underated by GM at 190hp. I think it actually put more like 220hp or something like that.


Troy,

This "whining" you're talking about, are you referring to me or the people that downtalk TPI?

I'm not stuck on TPI. However, I do like that immense ground swell of TQ that TPI gives you at low rpms. At least TPI gives you something. It's not a total piece of garbage like some on the TPI board make it out to be. The Superram and First Injection's setup will give you that plus the higher RPM capability. The best of both worlds I guess. More importantly though, I already have TPI on my GTA and I'd like to work with what I already have. For the time being that is.

 

I've heard that a Pontiac motor ruins 3rd gen cornering Still I would love to have a 455 powered 3rd gen.

 

You do have a 455, i saw it written on your hood

 

well I got my intake in today. It is a hybrid system.

 

Damn James, thats a beautiful piece right there...
I got a hybrid also, its new technology that has both benefits of a carburetor and fuel injection. Ive got a prototype on my car as we speak

 

Hey I've got that X 2 !

:lala:

 

Bret, Mikos is correct. In the early 80's the smog restrictions were so bad, and GM's R&D wasnt keeping up. The solution was to make the 305 the default engine across the board. But with the successful invention of the TPI intake, GM was able to meet the new smog tests, and the Corvette was able to keep its 350 engine. The f-body followed two years later after the bugs were worked out, and further improvements to the TPI system were made. But GM never redesigned the TPI for the 350 engine, so it was stuck with the longer torque producing runners. It sure would be nice if GM had made some shorter runners!

 

I think at the time of the design of the tpi that we were dealing with high fuel costs. G.M. had decreed that the 305 was going to be the largest V8 available in a car forever, in fact in the early 80's Vettes were not available with a bigger engine than the 305.
I think the reason they never developed shorter runners for the tpi is that they were developing the LT1 and the Ls1 systems, and the tpi was going bye bye.

 

does that make that washer run any faster...LOL

 

Russ,

The C3 Corvette was available with the 350ci during the early '80's. At that time you had either the optional 225hp L82 350ci or the standard 180hp? L48 350ci. I think the L82 was phased out after '80. For the '80MY, the 305 was the only engine available in CA. That's the only year for the "mandatory" 305 in the Corvette. Other states had the L48 350 as standard equipment as always with either a 3spd auto or the 4sp man trans. In CA, '81 saw a return of the 350 in the Corvette.

GM was very stagnant back in the mid '80's. The 85-'90 F-bodies had very little changes and upgrades during those years. I read an article somewhere, a long time ago, about how GM kind of basically ignored or forgot the F-body during these years. The reason GM didn't "upgrade" the TPI system for the 350 was because they didn't have to. The F-bodies were already selling like hotcakes back in the mid '80's. They could've put a 4cyl in them and they would've sold. Oops, I forgot! They did put 4cyl's in them during '82-'85.

If you ask me, GM went from one extreme to another with their intake systems. They went from low RPM TQ (21" LTR) setup on the TPI to the high RPM TQ (3" runner) setup on the LT1. They had to up compression to nearly 10.5:1 and use reverse-flow cooling for more spark advance to get the LT1 faster.