Black89TransAm

i was wondering how much better a TPI intake would run with my car, would it be worth it to switch from TBI or just to beef up the TBI, i also plan to get ram air, and i have found a kit for both.

Fast355

iTrader: (2)

You are asking the wrong board if you want advice on a TBI-TPI swap. I have made the swap and the TBI setup is better for most things when properly dialed in.

rockit

iTrader: (3)

it depends very much on what you are going for. but yes he's correct in saying that tbi is more appropriate for most things.

if you live near/race at an eighth mile track, tpi is a god at the eighth mile, i've taken cars with dr's off the line with my l98 and 3.23's what it lacks is top end. the same car that murders in a stop light drag, gets eaten up by cars i far outclass on the highway, moddability on a tpi car is also sooo much more expensive and constrained on tpi setups. it's also a very misunderstood setup.

tbi on the other hand, makes use of the older carb tech, and IMOP is easier to tune plus with the EBL now released so much potential has been made for these cars.also you have cheap and flexible options for cams, for intakes, for powerbands, it's just carburetion stage 2. plus given that scenario people like fast have allready done alot of what you may want to try so the "tech support" is there for it.

i suggest remaining tbi, you'd be surprised how much of a different world it is on this site hanging out in the tpi forums vs tbi, i think you can get more done on this board with less money and without dealing with half the attitude that you do on other forums, people are just more tolerant here

FreeLoader

switching to tpi has it's advantages.

it's a bit more efficient in the mid rpm's which is good(especially for autos) when cruising, specificially, though less than ideal for all out racing.

it also can get you to switch to a maf setup(though it's cheaper/easier to get an SD tpi setup if you're swapping), which can make tuning much easier, as well as making it easier to do general upgrades without throwing off the stock tune.

it also looks cooler, in my opinion.

unfortunatly, none of those reasons merit the $500 you need most of the time just to get the PARTS to make the switch, much less if anything is broken, or you don't know how to do it, or whatever.

tbi's have been switched to maf, ebl has made leaps and bounds in ease and accuracy of tuning(so i hear, I haven't personally tried it), and a nice, home made CAI/RAI setup can make you prouder while looking under that hood than any piece of metal will.

long story short, if you want to switch to an 8 injector setup, go with something aftermarket, you might actually see some gains there, the stock ones are hardly worth the money though.

and I agree about the forums. tbi owners are the underdogs, so there's always been much R&D around here to disprove the "suckiness" of our engines. as a result, you'll find that many of the most intellegent people on the forums are in the tbi section. not that the other boards don't have many knowledgable people, they most certainly do. the tbi board just has...more .

rockit

iTrader: (3)

tbi certainly has had the lions share of the innovation in the last 5 years.

Black89TransAm

im just trying to beat my friend

FreeLoader

then stick with tbi, your money will be better spent elsewhere.

Black89TransAm

would getting performance injectors help?

1988-305-tbi

ejectors would help on a moddified car, i even messed around with some different ones on my car, you dont need more injector unless you change your cubes i.e. go 350, or swap in a cam and some good flowing heads.

besides a nice vortec setup should work better than just going to tpi


A decent set of headers, and a full exhaust with some 1.6 rockers, and CAI/ RAI should put you about whwere the 5.0 tpi runs, but those mod are prob easier than pulling off your heads/ intake manifold/ running a new harness, and replacing your old fuel pump, which is necessary to run the tpi setup

FreeLoader

you won't need bigger injectors for a good while, so long as you tune the car to some extent. simply increasing the amount of fuel going into your engine isn't going to give you any power if you didn't need it in the first place, and if you're engine is still stock(or even mildly modified), you don't.

getting a vafpr would cover any extra fuel you'd need until you were well into the 200 hp range, but you'd have to get there first.

if you're looking for more power, look at the stickies at the top of the board, or in the various threads pertaining to making more power out of the engine, they all pretty much follow the same guidelines.
----------
https://www.thirdgen.org/forums/tbi/...used-what.html

perfect example.

Dyno Don

iTrader: (7)

Just go ahead and switch, no one that has done it has any regrets.

The TBI guys just like to prove their right, but only they can do what they do.

Black89TransAm

i think ill go with whatever is cheaper after all, im gonna be leaving the car home in a few months

CamaroFreak85

Ok let me get this strait....only guys with TBI seem to understand the system and be able to make power with the system......and you're surprised?

TBI is a speed density system, which requires tuning to make more than stock HP levels. A SD TPI system will require the same. Once you get this through your head TBI has very few limitations and the benefit of being uber cheap and easy to bolt onto a free flowing carb intake that will outflow ANY TPI style intake.

Dyno Don

iTrader: (7)

[QUOTE=CamaroFreak85;3415105]Uh...no just a select few!

Let's see...
In my neck of the woods

TPI systems in the 12's....7 (last count)

TBI systems in the 12's...0

Not too good !

(free flowing carb intake) Won't pass the visual so that's out.

Fast355

iTrader: (2)

[QUOTE=Dyno Don;3415462]I disagree as I run the 2.00" bore 454 TBI unit and factory TBI-Carb adapter from a 454. It is on a Vortec Carb intake with EGR provisions from GMPP. Underneath the intake is a pair of ported 906 Vortecs and a LT4 roller camshaft. The 1980 C10 pickup that it is in runs in the 13s with a stock stall TH350C and 2.73 gears out back. I've never had a problem getting through the visual inspection here in Dallas.



My 1983 G20s Edelbrock Performer Vortec intake lacks EGR provisions and I run a Holley Projection adapter plate on it with a 2.00" bore 454 TBI. It recently ran a 14.7 @ 94 mph in the 1/4 mile.

This engine made 369 RWHP @ 5,400 and 377 RWTQ @ 3,600 on a Mustang Dyno, its only 350 Cubic Inches.

FreeLoader

[QUOTE=Dyno Don;3415462]that's vague and general misinformation.

tbi camaros simply didn't come with the same options as the tpi's...the heads were different, the exhaust manifolds were different, the cams were CONSIDERABLY different, FAR better rear gear ratio's, the entire exhaust system was larger, hell they even upgraded your suspension, gave you an oil cooler, different fuel pump...should I keep going?

if you bought a tbi car, throwing a tpi setup on it isn't going to do anything. change out all those parts, then throw a tbi next to a tpi, then we'll see...actually we'll see that the stock injection system has little to nothing to do with it making 12 seconds, as all of those people have poured considerably more money into their motors than just about anyone on the tbi board.

so, you've proven nothing.

I've stated the advantages to a tpi setup, that's all there is to it. make your decision based off of that.


I'd also like to reiterate that I'm not at all against switching to tpi, I even actually like several aftermarket ones(stealth ram, mini-ram, etc). and in fact, if I remember correctly, fast355 actually has or had an engine he swapped to TPI, so this isn't a territorial thing.

just trying to give out real information.

Dyno Don

iTrader: (7)

Ok...I left out the one with a ton of money invested.

383 454 unit four barrel manifold.....13.20 Wow!

FreeLoader

can't say I know a whole lot of people on this board with E-tec 200's(or tremec t-56's for that matter)...most don't even have aftermarket heads. some do, but the majority of those people have invested in many aspects of their cars and are running similar times to what you're talking about.

BMmonteSS

https://www.thirdgen.org/forums/tbi/...ack-times.html

How about 11's ......with a 305????

Naaa tbi is completely uncapable of making power..

The key with TBI or any SD FI setup is in the tune. TBI requires a slightly different tuning strategy but is completely capable of making serious power, and more cheaply than most types of FI.

P.S. That was me posting under BLMcamarofreak, I was logged in as my brother by accident.

Kevin91Z

iTrader: (1)

One 11 second ET in a lightweight car by the TBI Superman vs hundreds of 11 second and faster ET's in TPI cars by regular people. But I am impressed its a 305. That takes more skill than luck.

Black89TransAm

wow, looks like it'd be cheaper just to beef up my 305 tbi

BMmonteSS

Hang on back up the TPI is great train and show me how many LTR TPI setups are in the 11's. Sure there are plenty of HSR, super ram, and mini ram setups in the 11's but that is NOT TPI.

I believe the "400hp TPI" thread going on right now on the TPI board shows that it's pretty tough to break 400 hp with TPI. Fast has shown that it really isn't all that tough with STOCK TBI parts if you have the motor to make the power. The truth is no one runs TBI, and fewer people even know that you can reprogram the chip. Therefore very very few people have the necesary knowledge to make power with TBI. Thats why we harp on the fact that you can make power with TBI if you know what you are doing, and why we back up that statement and supply the knowledge to anyone who is willing to work at it.

Don, why in the world are you shoving that "select few" BS around?? Sure not many people have done it, thats why we are here trying to share the information required to do it. If fast can do it with a set of ported stock heads and 68 lb/hr injectors Joe blow can do it with a set of AFR heads and 90 lb/hr injectors.

FreeLoader

*applause applause*

dimented24x7

iTrader: (2)

FWIW, TPI is only TPI when you have a TPI intake. In my book, with other intakes that take the tuned part out of teh equation, its then MPFI.

TPI was good for what it was, but it really forces the motor to make its power in the mid-range. Ive kept the TBI rather then have another TPI car due to the fact that I have more selection intake wise and the existing system was cheaper to mod.

Kevin91Z

iTrader: (1)

Ok, look at it this way then: thousands of 13 second 305 and 350 n/a TPI setups vs how many 13 second TBI setups? A couple hundred at most?
I consider the Super Ram to be a TPI setup still, since it uses the regular TPI intake manifold and TPI runners, even if they're shorter and use a huge plenum.
For performance in a thirdgen, there are a heck of a lot more fast setups for a TPI engine than there are for a TBI engine. You can still use a 7165 or 7730 thirdgen TPI computer on these setups, while a TBI engine practically requires an EBL or truck TBI computer to work.
You guys have done some great work in the last couple years getting TBI to perform, but the fact remains there are still more fast TPI setups, just like there are more fast LT1 setups, and just like there are more fast LS1 setups. The multi-port EFI setup is king.
Again, I have never known anyone who switched his V8 TBI to TPI and regretted it. And I have never heard of anyone who was sick of his TPI's slow performance and switched to TBI, but there are tons of the opposite.

FreeLoader

the number of people that have done it has no bearing on whether or not it can be done.

I'd have done it by now, if I had the money. or any money, for that matter. I'm sure many people can relate.

as to the various 8 injector setups, I'm stuck. I agree that they really are seperate systems(aside from the super-ram), since they do remove the "tuned port" aspect that's really bogging down the power potential of the tpi system. but I also agree that they are essentially the same in that they're all very similar 8 injector designs, and swapping them out causes FAR less issue with any tpi setup vs. a tbi setup. in a sense, the tbi being "carb stage 2" would be like the stealth ram or the mini-ram being "tpi stage 2". the main difference is that with tbi you can make a ton of power with technically stock gm parts(admittedly from a handful of different gm motors though) while you have to go to another company to upgrade tpi, the exception possibly being the modified lt1 setups.

none of any of that information matters though, as it has nothing to do with the point of this thread.

the question was whether or not switching to tpi would help him gain any power to "beat his friend", and the simple answer to that is NO. i think anyone who has actually read the thread to this point can agree with that. while a tpi F-BODY may have more potential overall, taking a tbi f-body and simply throwing on a stock tpi setup will do practically nothing. if it does make any gains, it'd be due to the improved air box design, not the fuel injection, and it would be ungodly cheaper and easier to build your own tbi air box or even just go open element to compensate for that.

so..there.

Azrael91966669

90 + tpi and tbi cams where the same exhaust was also the same

all i know is i went from having a slow tbi
to having a car thats keeping up with cars that used to have lengths on me

example my Buddy's mustang 5.0 gt with tbi not only did he kill me off the line he had 4 lengths on me by 70
with tpi i pull him off the line and around 40 he takes over but i stay on his *** all the way till 120 something tbi never saw and pass him up by 130 and can just wave bye to him at 140

not that anyone should be doing those speeds but i had to see what it would do with no limiter

i did all the normal things that make cars get up and go gears weight reduction but i couldnt get it faster then a 16.1

i havent took the car to the track yet but i can say tpi made it much faster
with the stock cam heads and exhaust

there is much more pull all over the powerband then tbi ever did
now i kick down the gas and can smile

FreeLoader

something doesn't sound right.

you'd have to be at like 4200 rpms in 4th gear to be making that speed, and tpi or tbi, the stock motor would take quite some time to get to that speed.

but basically, what you're saying is that after changing out a bunch of parts on your car, not tuning it, then switching it to tpi, you made more power.

suprising.

Azrael91966669

changed to better gears bumped the fuel psi alloy shaft for less rotateing mass and tbi still couldnt get out of the 16s but identical setup with tpi and im really makeing power
wonder why tpi didnt need any tuneing to make more power then tbi on the exact same setup


every one talks tuneing but yet why wont tbi react like every other fi system
i gave it the most free flowing filter i could find open element i tried a cold air but lost power in the 1/4
i gave it more fuel pressure all it did was waste gas
bumped timing all it did was ping
i gave it better gears and i gained a little but yet couldnt keep up with "stock" tpi cars with 2.73 gears
i tossed on a tpi and bam 2 differant worlds instant power when i hit the gas
may not the fastest car on the street but atlest i can keep up with 14 sec cars now before i was left in the dust any time a car with any kind of power pulled up

and makes alot more low end the i will admit the tbis torque converter is annoying with tpi but im beating tpi cars now that shows me the problem was whats on top the motor


all i know is i slapped a "stock" tpi on my car and now its faster then a modded tbi weird huh

Kevin91Z

iTrader: (1)

No, the camshafts were NOT the same. All 90+ TPI's 305 and 350 have the same larger 350 camshaft, regardless of options. The TBI's all have the small "peanut cam." Yes the exhaust is the same as the TBI's on 305 TPI's with the single cat setup.

Fast355

iTrader: (2)

This is just another case of lack of knowledge and a further indication of the mis-information that gets posted on the TBI setups.

Az seems to be putting ALOT of false information into this thread.

ALL 1990+ TPI engines recieved the L98 camshaft.

The TBI 305 had the PEANUT camshaft, 1 7/8" manifolds, and a 2.1/4" Y-pipe and cat (rated 175 HP).

The non G92 TPI 305 had the L98 camshaft and the TBI exhaust setup (210HP).

The G92 TPI 305s had BOTH the L98 camshaft, the larger 2.25" manifolds, and the dual cats (rated at 230 HP)

The tuning in the TPI ECM is worth probably 15-20 HP over the factory TBI tuning.

As far as adding timing to the TBI setup, that is shooting yourself in the foot, as is adding more fuel. The TBI setups have plenty of total timing and timing at part-throttle. It is the low rpm, high map part of the timing that needs help, basically more initial advance and a faster advance rate. The TBI engines run lean at part-throttle and go VERY rich at WOT. By advancing the timing you raise the total timing and the part-throttle cruise timing and welcome engine pinging. By increasing the pressure you make the PE air/fuel ratio even richer than it was stock (I've seen stock engines drop to 10:1 afr).

Speed density is speed density, it needs tuning to run correctly. If your TPI is a MAF setup, that would explain why it ran better.

The 187 TBI heads make a little more torque than the TPI heads and the 081s on the TPI make a little more peak HP.

Here is the cold hard facts for a TBI exhaust TPI 305 vs. TBI 305.

1990 TPI vs. TBI

Engine--------HP-------------TQ
TBI 305-----170 @ 4,000-----255 @ 2,400
TPI 305-----210 @ 4,400-----285 @ 3,200

As you can tell most of the extra 40 HP comes from the fact that GM shifted the powerband up 800 rpm with the longer duration, higher lift of the L-98 cam. The TPI intake limits peak HP from shifting up even further. The reason this is obvious is the cam specs and heads are virtually identical to the L69 which made 190 HP @ 4,800.

Azrael91966669

well then apperently the tpi engine i have is a ultra rare 1 off that has the same cam as a tbi even but even the replacement cam for these engines is the same one listed for tbi
from what ive seen only 5speed g92 cars got the l98 cam

any one wanna buy an ultra rare 305 tpi engine that has 081 heads and peanut cam?

also i swapped to a speed density tpi from a 90 formula same engine as noted above but only used the tpi

All 305 TPI (LB9) engines (1987-1992) came with one of two basic cam grind profiles
the best way to identify the type of cam on an LB9 car is to check the redline the peanut cams have a yellow line at 4500 and red line at 5000the l98 cams have a yellow line at 5000 and red line at 5500. thats about the easiest way to check other then pulling it out and looking for its pn

i am so tired of being called a lier about this spec or that spec
the formula i pulled the engine from had a 5000 rpm red line every G92 car ive seen has the redline set at 5500 even the 145 speed cluster i pulled from a 1992 g92 305 5speed camaro has its redline at 5500 yellow at 5000

Fast355

iTrader: (2)

ALL 305 TPI engines from 1990-1992 had ONE AND ONLY ONE CAM CHOICE, PERIOD, the L98 cam. If the engine has ever been rebuilt or opened all bets are off.

Replacement cams from NAPA, ALL list the L98 cam for 1990-1992 TPI 305/350s.

Furthermore, EVERY TPI engine has the SAME FUEL AND TIMING tables in the prom.

This was my dyno graph comparing my tuned tBI setup to a tuned TPI setup.

Azrael91966669

every non g92 car seems to have a smaller cam but whatever and a different red-line
ya i believe napa also lists the l98 cam for the tbi but then again napa will also sell you a cast iron 083 head instead of an 113 alloy head for the vette as direct replacement to bad the vettes intake wont even bolt on to it

and will put 187 heads on a lb9
i would never use napa as the ultimate guide for part numbers or what belongs with what

Fast355

iTrader: (2)

I never said that NAPA was the end-all of parts listings, but I do KNOW that the Speed Density TPI cars all have the same camshaft in them, the L98 cam. I also know the main difference in the engine of a G92 equipped F-body is the dual catalyst, N10 option exhaust system. That exhaust system is a 15-20 HP benifit to the car equppied. DynoDon even proved this with his 305 TBI test car. I can tell you also how I know this. Remember the 1990 LB9 automatic, non-G92 power rating that I previously mentioned. Lets take the 1988 LB9, auto, peanut cammed car and compare it to a TBI car. Then lets take all the L98 cam equipped cars and look. I immediately notice the similarity in the power ratings. The RPMs for peak HP/TQ are practically the same for engines with the same cam.

Peanut Cammed
1988 L03/A4---170 HP @ 4,000---255 TQ @ 2,400
1988 LB9/A4---195 HP @ 4,000---295 TQ @ 2,800

L-98 Cammed
1988 LB9/M5---220 HP @ 4,400---290 TQ @ 3,200
1990 nonG92---210 HP @ 4,400---285 TQ @ 3,200
1990 G92------230 HP @ 4,400---300 TQ @ 3,200
1990 L98------245 HP @ 4,400---345 TQ @ 3,200

BMmonteSS

AZ, you simply changed way too many factors when you did your swap to attribute them all to the TPI system itself. Like fast mentioned the reason you were so slow with the TBI setup is because of the lack of tuning, increased timing, and way too much fuel.

I know for a fact that I spend half the time tuning a 730 setup as I do tuning a 747. The ECM is just that much better than the old TBI ecm......yeah I said the TPI ecm is better than the TBI ecm. No one said that TBI is better than any other form of FI, we are just saying with proper tuning (even on the stock ECM) TBI can and will make as much or more power than TPI for way less money.

Enough internet babble, I'm off to tune a 350hp vortec 350 with.....gasp!! TBI on top

Fast355

iTrader: (2)

That is the honest truth of it the 7747 and 8746 TBI style ECMs in STOCK form SUCK. The slow 160 baud kills them. Recently, I have been re-pinning the TBI ECM connectors to use the late model TBI PCM. The PCM is a much better ECM using the same 8192 baud rate as the TPI ECMs. I have also been wiring the vehicles I switch to the TBI PCM with both the WOT A/C cut-out relay and electronic transmission provisions. That way when the 700r4 goes out, I can put a 4L60E right into its place.

Azrael91966669

so if increasing time is a big no no then why is it in one of the stickys
why on earth would anyone need a afpr then
all i hear about was a boost in fuel pressure and timing made for one fast tbi
i tried it ya i ran smoother and was "quicker" but even gears didn't help much
i ran a best time of 16.4 @ 84 with timing at 4 with 2.73 gears after trying desperately to beat my girlfriends 96 firebird at the track that was the time i won but was her worst run
0* got me constant 16.8s @82
8* got me a 17.3 but i also spun all the way threw the 1/8 mile marker one wheel peel sucked
then i put 3.23 gears and posi in mainly as i didn't want to repeat the losing streak and the embarrassing 1/8 mile worth of very expensive rubber

i tried the same adjusting both fuel and timing till i ran the fastest
that netted me 16.1 @86 ya i still spun a bit but then the 2nd run was a 16.4@88 had let it cool down and hooked but yet a worse time but yet my my 60 foot was better
ya could i have worked it into the high 15s ya i bet i could but what was the point i needed it to run a bit more consistently fast
i thought about keeping tbi but not only did i not like the look of it or the sound it makes sucking air sound from open element mind you ran both stock and open element it ran consistently slower with the stock in place

after doing so many things just to get beat by an old 90210 looking BMW convertible i figured time for tpi
i went from a modded tbi to a stock tpi and gained power ill see how much when i dyno it again
stock was putting down 153 hp @ 4100 and 231@2400 torque sae corrected
my mods got it to 161@4300 and 243@2300
open element added a whooping 3 hp and no torque
bumping fp from 9psi to 13psi made 6 more hp all threw powerband but peak hp remained the same
then messing with timing 4* got me the best overall results it made the hp peak at 161 thats how i "tuned" my car

made a car that ran stock a 17.2 consistent with a 16.9 "cold" every so often to a whooping 16.4 consistent with a 16.1 as the best

sofar I'm racing cars and beating cars that beat me badly before so what else can i blame other then tbi

i never expected the car to be a rocket with tbi but i was hoping with gears it would have at least made it consistent 15s

but i couldn't knock the 29-31 mpg it would get on the freeway with 2.73s and dropped to 28-30 with 3.23s it felt much faster but didn't prove that way on the track at lest it became fun to drive as slow as it was

so far with tpi I'm getting 30-32 mpg on the freeway if I'm nice with the go pedal
but i also get much better mpg getting on it i can get 300 miles to the tank city driving and just flogging the car for all its worth
before with tbi i mite have got 250 doing the same

no i know you will say oh but you boosted the fuel pressure hence you bad mileage stock 9 psi and 0* got beating on it a whopping 270 but also a sluggish
and not so fun to drive car
i came i saw i gave up
so far not one regret people do double takes at car shows
I'm much faster then i was before
and better mileage and i drive alot as this is my every season but winter driver
and so far i noted tpi dose a much better way of adjusting the fuel pressure via vacuum maybe tbi would have got better mileage with one of these fprs

i mean i made a 3.1 v6 run consistent 16.4 with just some minor mods starting out with a 17.8 i felt pretty good with that by just boosting fuel pressure and increased timing and minor little things like mod the intake and pull the padding from under the carpet it really sucked having my winter beater v6 rs being faster then my almighty V8 rs

1st all i heard was "get a V8" then i get a V8 and that was a disappointment and then all i heard was "get a 350" and keep tbi
i swap to tpi instead and it acts just like a Friends 350 tbi apparently tpi really was made to make a 305 act like a 350

i know my posts tend to ramble but he wanted reasons for swapping id say those are a few good reasons

FreeLoader

I'm sick of beating a dead horse really, but i'll say a few things.

1. 8 deg of timing is very high, most people who do advance their timing do 2-4 deg. and they switch to premium gas when they do.

2. 13 is fairly high for a completely stock motor, you only needed 11-12. did you bother to check any of the inbetweens, or did you just read up and go for max everything on an otherwise entirely stock motor?

3. you didn't do much to the motor overall, some bad tuning, and open element, and gears. the gears helped the most, but if you're running rich and knocking at higher rpms, it's not going to do much to help when you get better gears.

your tpi on the other hand has a different cam and heads...I'm sick of repeating this same **** over and over. if you're too thickheaded to see that tbi is feasable, then DON'T USE IT. I could care less either way, honestly.