I've seen a few TBI supportors say that the TPI sucks because GM put a 305 intake on a 350 engine.

Let me remind those TBI guys that GM uses the same TBI intake on 305 and 350 engines, too.

------------------
West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

TBI sucks becuase GM made it suck, they had a super small cam on it and very restrictive heads on them. TBI is great if you build up a whole new motor, single plane manifold and a higher CFM unit. What GM gives you is not the best though. TPI I good too don't get me wrong, they were in the vettes and the Z's and just got more ***** put into the lower half of the motor. If I were to choose between the two I would go with TBI, looks better and is easier to work with.

------------------
--Spyder--

1992 Camaro RS
LO3, T-56,centerforce clutch, ported and polished heads, Edelbrock Performer Intake, 14X3 Open Element w/ K&N, hiflow cats (and thats it), AC delete, alu drive shaft, 3.73 posi, 170 stat w/ fan switch, STB, Subframe connectors, KYB AGX, Eagle GSC, and poly bushings.

1982 Z-28
Project car, ZZ4 in the works.

 

TBI looks better?? I don't think TBI could make lower RPM Torque like the TPI either!!

https://www.thirdgen.org/messgboard/...ML/004958.html

------------------
Looking For:

87 IROC-Z 350 TPI
84 TRANS AM 305 H.O.

[This message has been edited by IROCZTWENTYGR8 (edited March 05, 2001).]

 

I say it "sucks" on a 350+ only because of the cost of modifying it. Other than cost its kicks *** on a mild 350.

------------------
-Tas
'89 Formula WS-6
[soon to be Torch Red with black hood and headlights =) ]

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Super GRK_Taz World
EFI & Intake Options
AOL IM: superGRtaz | ICQ 82881207

 

Oh sure, and the cost of a 350 engine, new cam, new heads, new TBI intake, and new TBI throttle body is way cheaper?

Damn, I didnt mean for this to turn into a which is better thread, just pointing out something.

 

so was I.

high flow TPI = Super Ram/Mini ram = $1000+

cheap(however not 100% legal alternative) = Holley single plane efi intake = $255 + $50 TBI to carb adapter + $75 454 TBI base to use as a TB. Injectors would be extra on both. Dunno how much TPI fuel rails would be.$600 for a TPI base and runners just seems nuts to me.

I'm not loyal to TBI, I could care less. I like EFI because I hate carb. I just want what's best for me that I can afford.

 

How can argue that TBI is better than any type of port injection? Fact remains that the TPI doesnt need to rev high RPMS, the off the line grunt and insane torque is enough to rocket the car off the line. Id rather stay below 5500RPM on the street with the TPI than go above that and risk breaking parts. The TPI is designed to exploit the low range and it does so with great effectiveness. Its simply a better design than the TBI, but I can see your point on TBI being cheaper.

------------------
'83 Firebird 2.8
'89 Firebird Formula 350
2nd owner, red/grey, t-tops, dual cats, and a 3.27:1 rear
K&N, TB bypass, No MAF screens, CAI, full Accel ignition

 

I had great success with my ported stock TPI intake. I dont see any stock TBI intakes running low 13's or putting 280 HP to the rear wheels.

And I bought my TPIS intake & runners for $400 from the classifieds. Cheap TPI is possible, and the gains are better.

 

we don't need to keep our stock intake because a NEW carb intake is only $100. How much was that TPIS stuff again?

 

If you don't mind I'm going to dive into this head first. Kevin, can you tell me who and quote any of us TBI guys saying TPI sucks because GM put the 305 intake on a 350?
I've been on the TBI board a long time and nobody ever says TPI sucks. We all think it's too expensive for OUR cars. TBI guys look at TBI as the imbetween and best bang for the buck.
I can remember me saying how GM put the 305 TPI system and only made like 15 more hp than the 305 from the factory. The 305 TBI system is on the 350 trucks and has been for a long time. The L03 came with 170hp mostly thanks to the higher compression than the LG4. The 350 (L05) trucks in the late 80's and early 90's (until vortec) came from factory with 210hp and 300ft-lbs. With the same intake different injectors. That's 40 more hp compared to the TPI difference of a 15. Obviously come from factory doesn't matter much since most of us mod the hell out of our cars but I had to stick those facts out in the open.
TPI was designed only for the 305, the TBI system was designed more for the trucks which came with both 305 and 350. I didn't forget that corvettes came with TPI 350 but they also came with crossfire injection! Vettes were just the way to launch a new intake system into the publics eye. That way everybody was like oh well it's on the corvette and now it's on the camaro, I'll buy it! The best part is they even used the TBI on the 454s hmmm...makes you wonder doesn't it. Sorry if I'm coming off as a jerk but I don't like people coming down on TBI, we don't trash about TPI and we don't talk trash about carb. It seems to me that most of the TPI guys here look down on TBI and the more you talk about it the more TPI guys reply with "TBI sucks, don't waste your money."
Some facts about TBI compared to TPI and carb: listed best to worst
1.Bang for the buck: Carb, TBI, TPI
2.Gas milage: TPI, TBI, Carb
3.HP: depends on how much is invested and that goes back to number 1.
4.Flat torque: TPI, TBI/Carb
5.Higher rpm hp: TBI/Carb, TPI (shorter runners, unless $$$ invested into TPI for mini ram setup)
6.Simplicity: Carb, TBI, TPI
7.Dependability: TBI, TPI, Carb
8.After ~150K miles: TBI=$0, Carb=$$ rebuilds to frequently, TPI=$0 or injectors $$$
TBI just seems right if you want a cheap alternative to TPI and other EFI. TBI is used all the time in high performance vehicles, they usually use SFI fuel rails like TPI but they use TBI intake design because of the options.
TPI is awesome and sometimes I wish I had it but not after I swap in the 330hp 350 next week. I'm much happier that I have 670cfm of intake and I can change manifolds for ~$100. I can install carb NO2 systems, use all kinds of superchargers unlike TPI. It just gives me more ideas to play with and I like that about the camaro. Heck, when I get a big block in you can bet I'll be using some form of TBI.
I hope this has cleared things up and if I sounded like a jerk then tough, suck it up and go kick an imports **** cause we're all owners of one of the best cars GM ever made.

------------------
, Jon (91 RS too many mods to list)

 

ok, i have spent a few grand on my engein swap in the past year, and i kept TBI. but here is the deal...how many of those thousands of dollars went into the actual TBI stuff? MAYBE 500 bucks.

now lets say you take a crate engine with a base price of say 3,000.

to add a carb, add a few hundred.
to add TBI, add a few hundred.
to add TPI, add a few hundred a few times.

its as simple as can be. why spend a TON of money on all this TPI stuff when you can have similar power and spend a LOT less with TBI??

and i am talking upgrades here, not bolting up teh old system to a new motor. that would defeat the purpose of the new engine (kinda). dollar for dollar TBi is just way cheaper than TPI as far as i am concerned.

which is better? whatever your car came with..because i think its STUPID to replace TBI with TPI or vice versa. keep what you have and WORK with it to get it where you want it.

if it came with TPI good...keep it and get a miniram or whatever.

if it came with TBI, cool...get a carb intake, an adaptor plate, ande a high flow throttle body and you will be all set.

in this world of mods that we all live in, nothing is better than anything else because there isnt really much of a comparison. but there is, however, a "cheaper" alternative, which usually turns out to be TBI.

just my $.02.

and by the way...my car hangs with the LT1s and LS1s, so TBI cant be that bad.

-brian

------------------
1991 Camaro RS - ultra blue metallic, t-tops
GMPP 350 HO crate engine - TBI, MSD ignition, SLP exhaust
700R4 - 2,400 stall converter, vette servo
10 bolt - coming soon - SLP zexel torsen differential, GM 3.73s
z28boy.fbody.com
z28boy@twcny.rr.com
AIM - "Z28 Boy"

 

Everybody got real quiet all of a sudden. Anybody disagree with me or z28 boy?

------------------
, Jon (91 RS too many mods to list)

 

Yes and no, as before said.

Cheaper yes, better no.

------------------
Looking For:

87 IROC-Z 350 TPI
84 TRANS AM 305 H.O.

 

If TBI is so much cheaper and better than TPI then why does GM use it still on all their performance fbodies? Seems like they would want to put something cheaper but effective to save money wouldn't they?

------------------
Eric Natzke
91 Firebird 305 TBI
"It Ain't Stock"
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

 

I guess it depends on what your definition of TPI is. I don't consider the LT-1 to be TPI. It is port injection though. So if you consider a "dry" intake to be TPI, then yes; GM still uses TPI. But I don't consider their newer intakes to be TPI perse.

I will have to agree with the cost effectiveness of TBI. Take the money we TPI guys have to invest in our intakes to get it to breathe and plow it into a an equivalent TBI motor and they can buy a lot more performance goodies (assuming the person will burn their own eprom for both).

Dollar for dollar, I could build a better performing TBI motor than a TPI motor. They have a $1,000 advantage to play with. Or let's put it this way: you can burn an eprom for either motor, I put a MiniRam (plus injectors and TB) with a cam but stock heads and the TBI guy uses that same money and puts on a set of GOOD heads, intake and cam. Who do you think will perform better?

 

91Bird, I think you're missing the point. Why do you think most people still use carb? TPI has it's advantages and haven't you noticed that ever car is dry flow now! Dry flow is better but harder and more expensive to modify and tune. It was setup for the specific engine/exhaust setup. When you start to mod things get stressed out. The length of the TPI runners is a good example. It's been proven that the length is very important. GM isn't going to go to wet flow again just because that's backwards technology, no good company does that. Eventually there will be super long intakes and direct fuel injection into the cylincers. The injectors will be right next to the spark plugs. Then I think GM will eventually get into the OHC and DOHC market. I think it would be a good idea for GM to stay competative. If ford used the DOHC setup on a 5.0 (instead of the small bore 4.6) then I can bet GM would have stopped making the camaro a few years ago.
Let me just say with $1000 I could get some really good heads or vortec heads and some No2 .

------------------
, Jon (91 RS too many mods to list)

 

Another obvious point that GM doesn't always go cheaper to save money: LS1 all aluminum engine. You think that was cheap? Although they are using a plastic intake manifold .

------------------
, Jon (91 RS too many mods to list)

[This message has been edited by JPrevost (edited March 08, 2001).]