i have seen a few post that say "TBI cant make power", "put a carb on and you will be faster." so lets post the Pros and Cons of TBI so everyone knows whats going on.

we all know that TBI(or at least 305's) got the shaft from GM. little a** cam, sucky heads, small injectors, little TB, and a small exhaust.

------------------
1992 Camaro RS
Mods:
Custom chip, 14x3 Open element w/ K&N filter, MSD 6a, MSD GM blaster Coil ,MSD 8.5 SC wires, AFPR,Fuel Pressure gauge,A/F guage, 3-Row Al rad. , 180* t-stat,Proform 1.5 roller rockers, Hooker 1 5/8 headers, 3" Catco cat, 3" Hooker Aero Chamber cat-back, "Ultimate TBI" mods, Nitto 555R Drag Radials

Next

454 TB,intake,SLP Posi,3.42 gears
Al Driveshaft, Underdrive pulleys,
LT1 cam. 2400 stall Tq converter

Best Time: 15.279@89.02MPH
Underdog Racing

 

please, lets not start this again. but if i were you, just do a search of the archives.

 

Yeah, GM made TBI look pretty bad by making it restrictive and then putting it on the most restrictive GM V8 right along with the LG4 with it. TBI was orginally made for emmisions and so was the computer controlled carb on the LG4. The LO3 and LG4 weren't meant to be performance V8's.

------------------
Eric Natzke
91 Firebird 305 TBI

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-180 Stat-3:42 GM Gears-Auburn Posi Unit-Edlebrock Strut Tower Brace-MSD Superconducters-MSD Cap & Rotor-MSD Blaster Coil-Rapidfire Plugs-265/50/R15 Tires-Emmison's all Gone-Free TBI mods
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 got a "Truckin'" mag where they made a 383 TBI with edelbrock parts and dynoed 450TQ. that sounds good to me. get some good tires and a torque arm and you're flyin.

------------------
-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

 

Let's take a look at the TBI system itself versus carb and TPI, not the engine it's bolted to.
Power band: Will make better high end power than TPI, since it isn't "tuned" for low end grunt. Will make better low end power than carb because of better fuel atomization since it's injected under pressure, not sucked into the intake. Maintenance: Intake manifold, and TBI unit; not throttle body, plenum, runners, and base. Also a very simple unit compared to a carb. What do the big time guys use: Look under the hood of the really fast cars at the strip, they'll be running a TBI system.

 

Andy89RS, you're right about the TBI systems having a higher rpm powerband. The cool part about TBI is the fact that you don't need to buy longer or shorter runners like in TPI. You just need to buy a spacer for the manifold to get that extra bit of low end. If only the TPI systems weren't so expensive. Another thing I like about the TPI is the faster baud speed of their computers. At the track a TPI system can get a lot more input from it's sensors. TBI usually get maybe 3 inputs during the whole ET. Oh well, still TBI is basically the bridge between carb and TPI or SEFI.

------------------
, Jon (91 RS too many mods to list), getting new engine in summer

 

TBI might make power above 4500, but 170 HP at 5000 RPMs vs 245 HP at 4500 RPMs, which would you rather have.

Also, do not confuse TBI with the MPFI that EFI cars use at the track. TBI has the injectors above the throttle body, which no serious racer uses. They all have MPFI, which is one injector at each port. TPI is a form of MPFI.

------------------
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=-

 

what are you comparing? I never heard of a 305 TPI making 245hp.

The exaust and air cleaner are major hinderences to HP. Andy should be making 230HP with his exaust and open element. stock crap cam, stock rockers, stock crap heads...

[This message has been edited by Tas (edited January 22, 2001).]

 

'


[This message has been edited by Dan W (edited January 22, 2001).]

 

What are u hiding Dan?
TBI can be made for performance. But so far, I don't see it on any high performance cars so far. Well besides some locals here on the board.

 

I was comparing the best f-body TBI vs the best f-body TPI. Forgot about the 305 vs 350 thing. The best 305 TPI was 89-92 at 230 HP. If you dis-count the dual cats, it was 205 HP. 205 HP > 170 HP. We'll find out the truth when my dad gets his car dynoed this week. Remember he took his stock TBI intake and replaced it with a stock TPI intake, on the TBI bottom end. It made 158 HP and 220 TQ at the wheels. We're guessing 190 HP and 260 TQ. 30 HP and 40 TQ just from an intake swap? I'm sold.

 

ya but how much did that intake cost? was it cheaper than a $100 edelbrock torquer 2? No doubt TPI makes kick *** power but at what cost?

 

yeah, I wonder what it would jump to if all you did was replace the intake and the TBI with better ones, it might have give about the same increase in performance for less money.

------------------
1989 Pontiac Firebird Formula LO3 Auto
-180 degree stat
-Hooker Cat-Back
*****Possible summer '01 mods*****
Open Element, Auburn Posi, Keyless Entry, wonder Bar off the IROC, 4th gen seats, T/A tail lights

1985 Camaro IROC-Z LB9 Auto
http://www.geocities.com/krt80/

 

LOL, 91bird305, What happened was I made a post but entered the wrong password hit the back button and only the quoted portion was there but I didn't realize it until it was too late. oops. Didn't have time to do it again.

I'm gonna save most of the long winded response I had before quote from a runner comparison thread on the TPI board:
https://www.thirdgen.org/messgboard/...ML/001057.html
"Here’s how a few intake/runner systems effected a warmed over 355 with "old style" 64 cc GM heads, Edelbrock RPM cam, and headers to compare EFI systems.

Performer RPM/750--323HP@5250/353TQ@4250... Ave-256HP/341TQ
RPM/Holley PJ TBI--333HP@5000/367TQ@4500... Ave-264HP/349TQ
Stock TPI----------296HP@4750/367TQ@3250... Ave-248HP/336TQ
ASM LTR (GM base)--328HP@4500/403TQ@4000... Ave-273HP/366TQ
Accel Super Ram----329HP@4750/378TQ@4000... Ave-260HP/347TQ
TPiS Miniram-------328HP@5250/355TQ@4500... Ave-257HP/341TQ"

Kevin, I saw that you posted on this thread. Did the selective vision go on when you got to the part where it shows that the TBI system has the second highest amount of power of 6 systems tested? Not bad if you ask me... especially when you consider its the only TBI player, beet out a carb combo and 3 out of 4 expensive multi point combos... were not talking just in peak power here but also average power. It also looks like the TBI combo is using an Edelbrock perf rpm intake... a dual plane intake! another handicap.


------------------
1988 T/A,
9" Ford, 3.50 gears, Auburn posi, 700r4 -w- 2100 converter
350 .060 over with forged 1 pc rms crank, and forged TRW pistons, 9.5:1 cr
Factory GM heads Pocket ported, 2.02/1.60 valves, back cut
Lunati roller 219/227, .479/.480, 112 LSA
Holley 700cfm 4bbl on TBI truck 7747 computer and chip by Howell-EFI
Edelbrock Performer EGR intake, Edelbrock TES and 3" cat

 

Yes, but Holley is not stock TBI, or 454 TBI, and it costs money just like upgrading to TPI. My dad found all his parts used, plus some of mine when I upgraded to TPIS base, runners, and TB.

 

True, the TPI engines all made more power than the TBI engines, that's why I specifically said let's look at the system, "not the engine it's bolted to". You can't possibly deny that 95% of why TBI engines are weak is because they came with heads, manifold, and a cam that only provide for a fraction of the flow of their TPI counterparts. One of these days someone needs to build a decent engine, and then bolt on a TPI, and then a TBI to the same engine and see what happens. I'd bet that TPI outpowers TBI only at lower rpms, where TBI will take over. I know someone will bring up the argument "well then why did Chevy put the TPI in the high performance cars instead of a good TBI setup". Easy: Low end torque is what feels powerful on the street, and that is where TPI is tuned. If both engines were limited to 4500 rpm, a TPI 305 would spank a Formula 1 engine, but I think we can all agree on what would happen when both are run in their powerbands. But then again, I'm more of a road racer, where you only spend the first 3 seconds of a half hour race at lower rpm, unlike drag racing where it's a reasonable fraction of the total time...

 

I've said it in the past and I'll say it again, in stock forms TPI has the advantage by far... because of the combinations they are used on and because of the stock RPM ranges used. There is no question about this, no one here denies it.

Who here gives a rats a$$ about stock thirdgen motors? Not I...I thought we were talking about the feasibility of using TBI on a performance setup and its pros and cons.

Back when I originally decided to run the 4bbl, I made an informed decision. I knew that the first thing I was going to have to do was start with a clean slate in the long block department... Everything there needs to be changed to make power no matter what form you decide to do it with. I also knew it was going to cost lots of money to convert to multi point… Fuel rails, regulator, fuel pump, lower intake, upper intake, runners, TB, Injectors air cleaner assembly, etc. The total cost added up to at least $1500 more than the TBI system any way I looked at it even if I used used TPI parts. When I looked at the short runner TPI intakes required to do the job, I decided that a short runner Carb intake would do just as good a job... and it does.

The guys here are guys with TBI cars wondering how to modify their TBI car and make power with their TBI car. I just showed an example of a very basic setup that works great...(about $600 cost for the TBI unit, intake and a few misc. small parts to install on an existing long block if used with factory ECM... custom chip required due to the additional fuel delivery of this TBI unit)

Why do you guys insist on keeping the blinders on? I've just given yet another example of the feasibility of TBI on a modified motor and its ability to run with and even beat the multi point guys on a playing ground where there are 3 of the best multi point combos around and only one good (not best) TBI combo.

 

Blah Blah Blah. To many words. Andy summed it up the first time.
*ALL READ*
TPI DOES BETTER THAN TBI IN THE LOWEND AND TBI DOES BETTER THAN TPI IN THE HIGH END. ALL SET? Sweeeeet.

 

I suppose the road racers in the Camaro-Mustang challenge all pick the TPI and Carb cars, because they suck in the top end? Uh huh... Anyway, we're going to the dyno tonight with my dad's car, and we'll see the difference between stock TBI and stock TPI.

 

*sigh* Kevin, Kevin, Kevin... Let's try it again: We are NOT talking about the engines as they come from the factory, we are talking about the system itself. Why do the racers in the Camaro-Mustang challenge all pick the TPI and Carb cars? Easy: the rules don not allow changes to the engine, so there we are at the stock engine again, which we are not talking about. Type this one hundred times, no cut and pasting allowed: We do not care about the stock engines that the systems were bolted to. Your reasoning is the same one that any 4th genner could use if you beat them at the track: their car stock is faster than your car was stock. I know you don't give a damn what stock vs. stock is in that case, so why use that argument here? :-)

 

This discussion is getting old.

 

i am semi new to this board and i have seen this more then any other topic.... TBI got crappy stuff why change to tpi? rather have a 350 tbi with a torqer2 intake a lt1 cam and some l98 heads then we'll see what your tpi can do... oops might of started a fire? i was told once the cheapest car you'll ever have is the one you already have... the tbi isnt as crappy as its rap.. give me 1 yr and i'll show some tbi speed..
Shawn
just for you tbi haterz

[This message has been edited by pimpintheRS (edited January 26, 2001).]

 

my TBI runs pretty damn good with those TPI guys (and the LT1s and even some LS1s for that matter). wait till i get some gears and tires. hehe.



-brian

------------------
1991 Camaro RS - Ultra Blue Metallic, T-Tops
----------------------------------------------
GM 350 HO Crate Engine - Vortec Heads, Edelbrock Performer Vortec Intake, Holley 670 CFM Throttle Body, Open Air Cleaner w/14"x3" K&N, SLP 1 3/4" Stainless Headers, Edelbrock Victor Series Water Pump, March Unerdrive Pulleys, MSD 6AL, Blaster Coil, 8.5mm Super Conductors, Cap and Rotor, Hypertech Fan Switch & Thermomaster Chip, AC Delco Rapidfires, 3" Cat Back, Flowmaster 40 Series Muffler
700R4 - 2,400 Stall Converter, Vette Servo, Shift Kit, B&M Super Cooler
GM 10 Bolt -coming soon Auburn Pro Series Differential, Richmond 3.73s
Brian's 1991 RS Central NY F-Body Association
Join the Third Generation F-Body TBI Web Ring
z28boy@twcny.rr.com IM name: Z28 Boy

 

z28 boy has alot of the mods i plan on doing the 350 motor and he hangs tbi isnt that bad the set up is.. get it straight haters..
Shawn

[This message has been edited by pimpintheRS (edited January 26, 2001).]

 

Nothing like the sound of straight headers.

------------------
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

[This message has been edited by 91Bird305 (edited January 26, 2001).]

 

funny guy.. you are one of the haters...
Shawn

[This message has been edited by pimpintheRS (edited January 26, 2001).]

 

i think that it could be safe to say, that everybody here has mixed feelings about tbi. im a tbi guy. i love it and i hate it. but ill probably never swap to anything else. because i think it will always be capable of giving me anything i need from an injection system.

 

So, other than a 3" exhaust system, a good air filter and a hyperchip, what else can be done to the sissy TBI 5.0 engine? Those are the mods on the car I'm buying (91 Formula).
In town, most friendly races last about four seconds, so how DO I get the edge over a 'Stang GT with that engine?

 

You yank the 305 and install a 350 or better yet buy a car with a 350.

 

What about the '85 (pre-peanut cam) 305 TPI? They made 215HP stock.



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'68 Camaro - Vortec 350
'85 Camaro Z28 - 305 TPI - FOR SALE
'91 Camaro RS - 305 TBI