http://tpis.com/faq.html

Q: I currently have a TBI system in a truck. I am in the process of rebuilding the motor, and am going to run more compression (10:1). I want to go with a bigger cam, what do you suggest?

A: If you go with more compression and a bigger cam you will not get it to run right. The TBI computers do not adapt to changes very well. And you can not even program them for the changes, it just does not work. If your really serious about getting more out of your truck you should consider going with a TPI type system. They are much more programmable, and they have a 17 inch intake runner which is excellent for torque, and towing. You could even program for a 420ci motor if you wanted.

Talk about an out and out lie...
The GM TBI truck computer (1227747) is probably the most widely used ECMs for custom tuneable EFI applications.

 

I thought our TBI computers are very difficult to program for some reason?

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Eric Natzke
91 Firebird 305 TBI (ZZ5 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-MSD Cap & Rotor-MSD Blaster Coil-Rapidfire Plugs-265/50/R15 Tires-Emmison's all Gone
http://members.aol.com/j007golden/91firebird.html

 

They are, after all, in the business of selling TPI stuff.

Kelly 'GhoSSt' Rosato

 

yup, thats nothing more than a good sales talk there.

 

TPIS is looking for your $3500!! Screw them, the greedy bastards!

 

I have a Turbo City TBI on a 383 stroker ( 450hp sbc), A custom burned chip from jet for my application and now I am having problems getting the tires planted on the pavement. I still use the stock computer from my old 305 tbi in my camaro.

------------------
91RS-STROKER

 

There is just so much utter nonsense floating around.
Who knows, given time, might even get away from the flathead ford days of 160dF thermostats are a good idea

 

hahahah thats been on their page for years

those guys are some of the KING ripoff artists out there.. they make tuned port injection sound like some sort of black magic for your engine




[This message has been edited by Pablo (edited December 01, 2000).]

 

Q: I currently have a TBI system in a truck. I am in the process of rebuilding the motor, and am going to run more compression (10:1). I want to go with a bigger cam, what do you suggest?
A: If you go with more compression and a bigger cam you will not get it to run right. The TBI computers do not adapt to changes very well. And you can not even program them for the changes, it just does not work. If your really serious about getting more out of your truck you should consider going with a TPI type system. They are much more programmable, and they have a 17 inch intake runner which is excellent for torque, and towing. You could even program for a 420ci motor if you wanted.

Talk about an out and out lie...
The GM TBI truck computer (1227747) is probably the most widely used ECMs for custom tuneable EFI applications.

The TBI copmputer can be programmed by getting a different chip the same way the TPI can and will work just fine. To lie about stuff just to make a profit is horrible.
I don't feel like going on. Stuff like that is bad PR for YOU. Click here if you want to see what I mean. Congratulations 5000 people now think worse of you(yes between this club and 2 other big ones the same people visit memeber is over 5000.)

TPiS: Have you ever tried tuning a TBI vehicle for a wild camshaft? We have, and have had no luck at all. We have had many people try to build high compression 383 and bigger motors and they just do not work out, or 350's with healthy camshafts. Maybe you can shed some light as to how to program a TBI computer. Because there is a big market for it. I no what a pain it is to tune by trying to tune them, and also hearing from TBI owners with built motors how they can not get it work right. I here this about 2-5 times a week! And they call us to see if we can help with a chip, or tech help, and we can not. We do sell cams for TBI (small ones), also larger throttle bodies, air filters, TBI spacers, and can tune TBI for a mild or stock motor. So it is not as if we wouldn't make any money from a TBI consumer. The biggest problem is the cam, you have to go mild or it is typically a headache. I have even talked to people that have built 383's and opted not to change the camshaft, or go with a mild cam, they ran great. Then at a later date they decide to add more power, so they try a bigger cam. This is where the problems come in. I have talked to A LOT of TBI owners who have spent A LOT of money on there TBI system, even going to after market systems to correct it and they still do not run right. So from my point of view and experience I feel I am saving people money by informing them of this. Maybe you can give me a number of a reputable company who can tune for a large cam, and when people call, I will gladly give them the phone number. It will save me a lot of time on the phone, it's not like were trying co convert people over to our systems. Bottom line: It is a "frequently asked question" this is why it is in our FAQ's section, and this is our "frequently told answer".

Respectfully,

TPiS

P.S.
I have changed the "FTA" on the FAQ to this:

Q: I currently have a TBI system in a truck. I am in the process of rebuilding the motor, and am going to run more compression (10:1). I want to go with a Large cam, what do you suggest?
A: We can not and will not tune for a wild TBI type setup. I would recommed running a mild cam, I here a stock LT1 cam works great.

I could of been more clear as to how much bigger of a cam. I meant a decent cam for making power. This is the first time I have had any feedback to this. Of course you can run a bigger cam, but not much bigger. Non of our performance roller cams for TPI, or LT1 would work. A TPI intake will make more torque than a TBI (torque is what you drive, and need in a truck) I am sure we agree on that. I would like to see a 420ci built motor, 520+ HP on motor, run with a stock TBI system. I do not believe it can be done.
TPiS

 

wow would ya look at that, I wonder what is so troublesome for them. If they are reading this, to answer their question: Yes, ive tuned for a 214/224 112 on a single plane on a teeny little 305 (mine, 7747, without even a scan tool!)

atleast he was cool about it and changed his page


" I would like to see a 420ci built motor, 520+ HP
on motor, run with a stock TBI system. I do not believe it can be done. "

I wonder if hes implying that that can be done with a stock TPI system hehe

 

Try going to Turbo City at http://www.turbocity.com/ Tom Millar, the owner, knows quite a bit about tuning TBI, as its their bread and butter injection. But they charge real $$ for it.

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

 

Not that much, they told one member that they couldnt tune for his cam, he ended up doing it himself and got it perfect

ive spoken to them a few times on the phone too and they werent that sharp

 

We are talking about tuning the computers. Not the intake itself, we offer more than just TPI intakes. If you run a 1227730 S.D. computer on a 420ci motor with our Mini-Ram, you will see 520-560 HP without too much trouble. We have an intake that will allow this. You are correct,a stock long runner setup like the tpi, will not allow this. But the short runner Mini-Ram will, so it can be done (tuned). I am sure if we had the car here we could tune for your 214/224 cam in a TBI. But over the phone it is not worth it. For us or the customer who has to send the chip back and forth. I beleive the biggest problem is vacuum, and am sure an adjustable MAP sensor would help a lot.

 

yeah right, good thing i only put on heads, intake, 1.6 rockers, ported tb, bigger injectors, a very free flowing exhaust, change the vehicle weight, torque convertor, and probly a bunch of other things that make the computer wonder what the hell is going on and i am only going low 14's on a stock computer and cam.
i really didn't think that there were people that stupid left in the world.

lata
tim

------------------
91 Camaro RS-LO3,Auto.
14.301 @ 94.39mph
The car is going street strip for next season. 13's here i come!!!!!
Edlebrock TES Headers, Cat Eliminator Pipe, Borla Adjustable Cat Back,Marche Pulleys, HyperTech Chip,Transgo Shift Kit,B&M Convertor(2000stall),Steve Spohn Rear Rig( all rod ends), Poly Front Bushings,Ported TB, 350 Injectors, Edlebrock Performer TBI Intake, Performer Heads, 1.6 Roller Tipped Rockers

 

Well, thats the idea, You probably have put together enough miniram combos to have a real general calibration ready right off the bat because of your in house testing where as you dont get many people asking you to do 7747 + TBI 500+ hp setups. I also understand that you want to sell your in house parts such as the miniram rather than holleys or GM's and someone elses carburetor manifold. Not much of a profit margin there, doesnt make much business sense to just sell chips on combos youll need to go back and forth via telephone or email to get right. So in reality, your stated specialty is tuned port injection not throttle body injection which is alltogether different than saying throttle body cant be done because of the ecm when both the 730 and 7747 are speed density based and are otherwise similar enough in terms of the guts to run the same motor identically (be it port injection or whatever, there are lots of folks out there running pfi setups with a 7747)

i think the key is parts

your typical miniram combo is pretty standard
x injectors
x displacement
x heads
x y or z camshaft

x kind of car

once you get a few nailed its probably alot easier to send a chip out the door the customer is satisfied with.. after all you did a car just like it last week


the only thing standard on a tbi car is the fact that its tbi, can be built as a short duration dual planed stump puller in a truck
or a high rpm screamer
both very different fueling, cam, heads, manifold, vacuum.. theres no standard choice like a miniram setup (ive never heard of a miniram stump puller)

the difference is like a mass produced suit vs custom tailored except a custom tailored side of it you only have a picture of the guy you are making it for and no measurements, the mass produced unit you are only making for 3 or 4 sizes and youve made enough of them to get all the proportions just close enough for those 3 or 4 body types to where the buyer doesnt complain

in the mean time I'm content with my cheapy unique home made brew of a combo running off my chip and the podunk ecm

 

Plastic 1,

Just wanted to say thanks. I have some respect for you for coming forward and making the change.

TBI definitely has its place among the $ challenged crowd. Ed Write from fast chips has done tuning for some board members... one board member Texas Heat has a real stump puller of a 2bbl TBI 350 in his car, tuned I believe by Fast Chips in house. http://www.fastchip.com/

Check my signature for my combo... its got a mail order chip by Howell Engine developments. http://www.howell-efi.com

You might consider those companies for your TBI customers special needs.

------------------
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
Comp Cams 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

[This message has been edited by Dan W (edited December 02, 2000).]