I just don't get it. Everyone seems to think that TPI is the big bad boy, but the problem is, it only makes 15 more HP on the same engine as a TBI (I heard this somewhere, am I right?), but TBI makes more torque. 15 HP is an easily obtainable gain on TBI and it costs far less then anything for a TPI, just look at the cost of a damn MAF sensor. And people seem to think that the best way to make power on a TBI engine is to put a carb on. Why would you do that? For the cost of a conversion you could get a whole slew of TBI performance parts (like a Holley 670) and make more power then a carb and get better fuel milage. I just don't get it. Is it just because stock TPI cars have more power the stock TBI engines? That's just plain stupid. TBI engines came with wimpy cams and heads that don't flow for ****. Plus, what do most people compare the TBI 305 to? A 350 TPI of course! That's a 45 cubic inch difference, what's to compare?!
Sorry, I'm just pissed at the stupidy of some people, someone asked "Why the hell would you want to put two TBI's on that engine? To double the suckiness?" (he was referring to my 427 DTBI project, see www.theduke.cz28.com for more info on that). If TBI sucks so bad then why does my little 327 with a TBI take down 350's with TPI? I don't have anything special for a cam, and the heads are just 305 TPI heads that have been ported and polished.
The ignorance of people just pisses me off.

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1992 RS
327, Modded TBI, Rebuilt WC T-5 5-speed, PRO 4 15" rims, Nitto's, 3.73's, Soon to have SLP 1 3/4 headers and a few other things.

 

hello duke,
i'v been think about the duel TBI you are doing and the one from gr8ride.com,
i'm trying to do this for a SBC(i hope a ZZ4 ) what kind of problems have you had so far.

BTW, i use to think TBI was ok, but TPI was the best. but after doing the mods, and seeing just how little it has to work with i dont think i'll ever switch.

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(A.K.A FireBird88)
AOL SN: Zander0710
1992 Camaro RS 25th anniversary edition Adopted Feb,14 2000

Mods:
14x3 Open element w/ K&N filter, MSD GM blaster Coil and 8.5 SC wires, AFPR, 60psi. Fuel Pressure gauge, 3-Row Al rad. , 180* t-stat, Hooker 1 5/8 headers, 3" Catco cat, 3" Hooker Aero Chamber cat-back



[This message has been edited by UnderDogRS (edited October 01, 2000).]

 

they get the idea that TBI sucks from magazines. they used to say that fuel distribution on TBI is never even close to TPI with its 8 injectors. boards like this prove that TBI can have *****. and it is much cheaper than TPI.

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AOL IM: superGRtaz
ICQ: 82881207

 

Problems? Where shall I begin. I had a custom wiring harness made for me that didn't work at all, so I got creative and made my own. It works pretty good now. I'm having alot of problems getting the stock computer (with a chip change) to work with two TBI's. I'm kinda tricking into thinking there's only one TBI, but it keeps screwing up the fuel mixture at certain RPM ranges, and I'm having trouble getting it to idle smoothly. I only tried it for a few days on my 327, and it was a bit much for such a small engine, but I found that tuning both of the TBI's together is tough. I use a DVOM to test then set the TPS's, then I had to get the throttle linkage to work them evenly, and the throttle air control things won't stay adjusted like I need them to be. Also I need to get a taller hood, this setup sits a little higher then the single TBI setup.
Once I get all the bugs worked out I'm sure it will be a beastly induction setup, I just need to learn how to tune everything together.
BTW, I think I'm going to ditch the GM computer and I'll just use a good HalTech procesing unit, their far more versitle.

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1992 RS
327, Modded TBI, Rebuilt WC T-5 5-speed, PRO 4 15" rims, Nitto's, 3.73's, Soon to have SLP 1 3/4 headers and a few other things.

 

Hey Duke - pretty sweet to hear of someone else doing this! I have two Holley 670's that I have going on a stroker 383 via an Edelbrock dual quad manifold. I have been looking into this for awhile now and have found out a couple of things. You may have to run a separate set of drivers for the second TB. Apparently the "signal" breaks up at certain rpm ranges (I think this is more for OEM stuff than Holley, but idunno.) I'm tracking this "extra drivers" thing on the DIY_EFI and GMECM list, currently. You may want to look at Turbo City. They have a harness to go from a single TBI to a dual TBI - give them a call and see how they work their setup - maybe they have extra drivers in there somewhere. I was going to just flat out remove one of the TPS's and one of the IAC's. That way the computer still only has to drive/listen to one of them; forget trying to work both of 'em. After all with the dual linkage, both of the TB's will be open the same amount and the one IAC should be able to accomodate the amount of air required at idle. I have a Haltech that I plan on running my machine with, that way I can throttle back on the fuel a bit to make it "runnable." Interestingly enough, if I read the documentation correctly for the Haltech, it has the capability to drive a second pair of injectors - you just have to wire up a second harness to them.

This is all preparatory to adding twin turbos of course. (They're already in the garage and manifolds are on the way!)

Steve

[This message has been edited by scauffiel (edited October 02, 2000).]

 

No, personally i think it comes from when they get a 305 tbi and then race a 305 tpi or here about 305 tpi's and they get killed. Seriously, i hated my car when it was stock. I got beat by my friends slighty modded Probe GT and i was like, this is the crappiest engine ever made. But since then, i have modified it and i belive its a pretty stong tbi, even though it still have the stock manifold and tb unit on it and the peanut cam and restricted heads and......well you see where I am going with this.....tbi (LO3) engines are all restricted and the TPI ones were already opened up.

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Eric Natzke
91 Firebird 305 TBI (dropping in a 355 summer of "01")
ASCD Ram Air Hood-3" custom exaust-Flowmaster 80 Series-No Cat-Edelbrock TES Headers (coated)-March Pulleys-TBI Spacer-K&N Open ELement-TransGo Shift Kit-B&M Supercooler 28,000 GVW-Hypertech Thermomaster-160 Stat-3:42 GM Gears-Auburn Posi Unit-Edlebrock Strut Tower Brace-MSD Superconducters-Accel Cap & Rotor
-Rapidfire Plugs-Pablo's Free Mods-265/50/R15 Tires-Emmison's all Gone

http://hometown.aol.com/J007Golden/index2.html

 

Ive heard all the same things, TBI sucks, well you know what, my car is running right now while my friends TPI Camaro is sitting at home, because he has to have a new expensive MAF sensor. Hehe, ahh, the simple things. Later, Jimmy