brodyscamaro

Ding, ding, ding. That's the reason. You gotta face the facts that budget is going to determine how fast you go, and without a good start (LS1 car for example) it's going to take some cash to hit 12s or 11s....

But all in all I say TBI just isn't great for HP. Use technology to your advantage IMO...

Free Bird

iTrader: (1)

Anyone who buys a 3rdgen, regardless of TBI, TPI, or carb, is on a budget. That's why most of us buy a 3rdgen, we can't afford the newer f-body.

My point, TBI is one of the worst induction systems put on these cars. In the long run it would be more rewarding to put TPI, aftermarket f.i. or even a carb on the motor. Complete TPI stuff can be had for $300.

My original question was why is sucked so bad or why it was so difficult to find parts and upgrades. BMmonteSS gave me the information I was looking for.

BMmonteSS

Figures you would pull the old "why screw with TBI when TPI is so great" crap. TPI sucks worse than TBI for a number of reasons.

1. in stock form the intake is a huge restriction above 300 hp.
2. It's expensive to upgrade
3. It's hard to work on (torx bolts, and you have to remove the plenum for everything.

why TBI is better

1. 454 TB's are cheap (100-150$) outta a junk yard, at 50mm they're bigger than a TPI TB
2. You can use ANY aftermarket carb intake, some like the performer RPM flow right up there with the stealth ram.
3. It's CHEAP
4. We will have the ElB soon, which will have code that blows TPI code outta the water.


Up to the fueling limitations there is nothing wrong with TBI other than it's a wet flow system. Same as a carb. Above 400HP or so and I would move to another form of induction, it sure as hell wouldn't be TPI. Most likely a converted single plane, or stealth ram.

Free Bird

iTrader: (1)

Then why are so many TPI cars faster than TBI cars. Is it just the fact that most of them came w/ 305's?

Factory TPI will support quite a bit more than 300hp. I think you know this.

crrllmich

You could run 9s with a TBI......switch to a Accel 1000CFM TBI unit lol.

BMmonteSS

TBI cars and trucks are slow, not because of the induction, but because of the heads and most importantly the cam. The stock TBI cam is a paltry 180 deg duration and .380 lift.

TPI will make much more than 300 hp, but I said that the stock TPI system starts seriously hindering power past 300 hp. Once you approach that mark it gets expensive with injectors, runners, TB's and aftermarket bases.

If you wanted to compare engines that came with either system, then yeah TPI kick the dog crap out of TBI. If you want to just compare stock for stock systems from the cylinder heads up, TPI still has an edge on a stock TBI system. TBI really shines when you take advantage of the fact that you can use ANY carb intake out there. With a free flowing intake and 454 TB, you will be able to SUPPORT 400-450 HP much more cheaply than you can with TPI and whatever upgrades you need. Your looking at 300$ for a TBI system that supports 400-450 hp. With TPI you need injectors, runners, and possibly a TB. Say 100$ for junk yard 30 pph injectors, 280 for any decent runners your already past TBI's 300$.

The problem with TPI is that it's designed to make low and mid range torque, which is great in a street car, and perfect in a truck. The problem is that when you start building the engine for HP the whole system is just tuned for the wrong power band, with it's small and long runners. Thats why the stealth ram is so popular. Once you swap to a sytem like the stealth ram, your no longer "TPI" so I consider this to be the next step when you want to make more than 400 HP.

dimented24x7

iTrader: (2)

Has anyone gone 11's yet with a stock TPI intake? To my knowlege no. And as far as Im concerned someone with a high $$$ intake doesnt really have tuned port injection anymore since alot of those strive to take the tuned part out of the equation and let the motor breath and make power.

On that note, Id say neither system is good for high HP numbers. The high water mark for numbers obtained by people with mostly stock TBI and TPI induction systems have been the same.

Dewey316

Because they switch to HSRs, mini-rams, superrams, LT1.

Not many 305's with untouched TPI, that are faster.

Dewey316

Mod edit: Deleted for content.

crrllmich

HAHAHAHAH!

92_ZED

I would imagine that this guys time just blows past the 11 second barrier:

https://www.thirdgen.org/techbb2/sho...hreadid=216278

I'd say that about proves that TBI is no slouch.

Free Bird, instead of coming here and causing trouble, go check out the fullsize site forums. Lots of big truck consistently running in the 11's and 12's with TBI.

Zed

90FormulaWS6

ill take any N/A 305TPI car from a roll

Free Bird

iTrader: (1)

I don't have TPI anymore, and I'm fully aware that it isn't that great of a performer. Other people in this thread explained why stock for stock the TPI motors are better/faster, and that's what I was after. I did have real interest in this thread.

I expected a much more mature and informative response from someone who has been on this board as long as you have. I've read your posts elsewhere and they've been helpful. To say the least, I was a bit dissapointed from the above statement. Have a nice day, and happy motoring.

dimented24x7

iTrader: (2)

Thatll be enough of that.