iain.thornton

Hi I understand cars in general, but I'm new to F Bodies

Can someone tell me the exact difference between TPI and TBI?
I'm not a novice when it comes to fuel injection-I just don't know the difference between these two specific systems

thanks for any help

Dale

iTrader: (12)

TPI looks like a silver spider.
TBI looks like a carb.


TPI has a fuel injector for each cylinder, has runners, and a throttle body facing the front of the motor. Is generally more efficent then TBI or a carb.

TBI works almost just like a carb. Except rather then fuel just getting poured in, its sprayed with 2 fuel injectors. Is generally more efficent then a carb

Both have sensors all over the motor, controlled via a computer.

iain.thornton

Ah right so TBI is just a more primitive system than TPI?

Dyno Don

iTrader: (7)

Bingo....you are correct!

Street Lethal

iTrader: (16)

I wouldn't say more primitive, just less complicated....

Jproz1167

iTrader: (3)

TBI

Alot less bolts to remove it (always nice) .. Dinosaur in nature yet reliable for everyday moping around and still able to outrun most people on foot. Low end torque pretty much taxi cab like but easily overcome with 373 or 410 gears.
Looks wise not much you can do aside from a chrome air cleaner.

TPI

Many bolts to remove it. Dinosaur in nature but unlike TBI can evolve into something better. Has the ability to outrun even the best of athletes and most cop cars (although I don't recommend this)
Looks wise, all polished out all you can say is WOW

I was bored and wrote this it's not meant to insult either system so please dont use it to open a war LOL

TA

iTrader: (1)

The TBI is both more primitive and simpler than the TPI. The critical difference is that the TBI is pretty much a 2 bbl carburetor with 2 "shower style" injectors mounted above the air horn, whereas the TPI unit has an injector squirting into the cylinder head port for every cylinder. Thus the TBI intake manifold is "wet", and the TPI intake manifold is "Dry" (just air, no fuel), which solves a number of efficiency problems.

Unfortunately, the TBI engine packages as delivered in 3rd gens are pretty lame compared to modern powerplants, but they can produced decent power (most '90's Vortec trucks are TBI, and they produce very respectable power) by changing just about everything from the oil pan up. Not quite as efficient (less power and mileage) as port injection, but very simple, reliable and cheap to produce.

The TPI intake system has so many parts its very complicated and expensive to produce, so were not as made in the same numbers as the TBI. Very trick looking, but designed for low-end torque and strangles the engine up high. This was really one of the first fully computerized mass-produced port injection systems, and many features of this system are used by just about every manufacturer in the world to this day, but in it's stock form is somewhat archaic. The TPI system is also capable of putting out good power, by again changing everything from the oil pan up.

Today's awesome LSx Corvette power plants are an evolution of the TPI system introduced in '84 Corvettes, so I predict early TPI cars will become collectors items.

C-ya


TA

Jproz1167

iTrader: (3)

84 vette had CFI not TPI

rgarcia63

Althought it's called cross fire (guess I should say I call it cross fire, did they cross the firing order?,)LOL it's a misnomer, it's cross TBI, a wet system, true not a TPI, but is an attempt to use long runners and therefore the precursor to Tuned Port Injection. A Tuned Cross Port TBI would be a better description.
Yes, I know it's cross fuel injection, but Cross Fire sounds so much better.

Trinten

Hey guys, sorry to dig up an old thread, but this one seemed to be the best place to start out of all the ones on TBI/TPI I've read.


I'm posting here because out of all my google searches, this place seems to have the most things in common, lots of discussions on TBI and TPI, and lots of turbo discussions, and it's a community that is familiar with my engine.

I've got a 350, currently with a carb. Expense aside - I'd really like someone to help me figure out the best way to go and what to get.

This gets complicated a bit by two factors - the first is that I'm also planning on tacking on a turbocharger, secondly the engine is sitting transaxle because, well, it's shoved into my Fiero.

Here's a picture of the engine compartment. This pic is about 2 years old, and I apologize for the engine being dirty. You'll see because of the way the engine is orientated (and I take more pics if you guys need them from different angles or something), I'm not even sure if the TPI solution would be viable (since room is limited on the passanger side, unless I'm mistaken about which way the TPI would or can sit).

Now if the TPI can sit with the intake facing the driver side, then great, because there's actually a decent amount of room over there, and that's where I was planning on sticking the turbo, and using the original air intake opening on the driver side of the car to bring in fresh air to it.

The more information, the better. If you have a preference towards TPI, please explain why, and let me know if you have any preference on company/kit. From what it *sounds like* (please pardon my ignorance here) a TPI system using a MAF would be provide the most efficient, tunable option, with only a mild power loss up top if enough air flow is provided (assuming the usage of things like knock sensors, wideband o2, etc)?

tinymay

Almost to the bottom of the page you will see a side mounted throttle body on the FIRST plenum. Put an elbow on that and you are looking at your inlet air. It's made to fit tight places like yours...
http://firstfuelinjection.com/products.htm
Active group purchase going on:
https://www.thirdgen.org/forums/grou...ml#post3964043

First elbow I came across...
http://store.summitracing.com/partde...5&autoview=sku
the FIRST throttle body looks as if it will need a round shape instead of the oval type I linked you to.

Be sure and post pics as you build... Looks like a cool project!!

Trinten

Hi Tinymay,

Thanks for the links, I'm reading up on the first one now.

So I'm guessing that you're a big proponent of firstfuel - and since there's a groupbuy going on, that alot of other people are as well?

Do you know of anyone that has tacked on turbos to their equipment?

I see for one of their complete kits they note it is a speed-density system, but "works well" with MAF. Do you know if they would provide help with a MAF setup, or should I just buy the hardware from them and look someplace else for all the sensors and electronics?

Thanks again!

tinymay

Yep, I'm pumped on FIRST for the mechanical arrangement that fits my current plans. I'm still waiting on perfomance feedback from the guys that install one in the near future. By the time Uncle Sam gives my tax money back, I'll be ready with the order slips. That's the plan, anyways.

The way I read it was they offer both MAF and MAP. The base electronics package was MAF. Maybe I should go read it again.

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

Well, you're right. Now I gotta regroup.
I was going to use my old MAF electronics.

Dale

iTrader: (12)

I think you would have more problem installing the TPI system due to clearance. However, IMO it would look better.


Another setup you could look at, and if you have some fabbing skills. Early 90's caddys used a throttle body smililar to what most know, but it has no injectors in the body. The injectors are port injected.

So i'm thinking you could possibly use a camaro or truck lower intake(they are different, the trucks sits higher). Drill and heliarc in some injector bungs, then some fuel rails, use the caddy TB. The same caddy also uses a trick looking airhat that could be fabbed up to make a CAI.

Also, if your good at wiring and go with some sort of port injection. Look at the top of the TPI board about installing OBD2 on it. You can go with a single coil, or 8 coil packs like the LSX.

Trinten

Wow Dale,

That would be a really impressive idea... sadly alot of that goes way beyond my skillset, and I'm not sure my mechanic would feel comfortable doing that (he already hesistates on doing of the things we've talked about, always adding the caveat of "I'll install whatever you hand me, but you can't hold me responsible if something goes wrong because of your parts." Which I can understand.

That's why I'm trying to figure out what I can buy and hook up. As far as clearance goes, I have another decklid in my shed that is slated to be modified to accomidate whatever I ultimately end up with.

The only reason I'm looking into doing the injection work is because I want the thing to be streetable, and try to eek out a little more MPG at the sake of some performance (right now it only gets about 12 mpg!! and this car weighs next to nothing!)

tinymay

12!!! I'm banging 19-20 in my square shoebox Jeep with a 350. Something ain't right. In that little rod you should be gettin at least 16-17.

Trinten

Tiny,

I *wish* I got that much. Maybe I'm just running the thing to rich, but you wouldn't know by trying to start it up. You try to start it up without spraying some starter fluid down the barrels and you'll be cranking it for 10 or 15 seconds, tapping the gas, before it'll even start to sputter over.

Once it's running it runs strong, idles around 800 rpm (when the engine is cold it idles higher for some reason about 1200 - might just be the throttle getting stuck and it loosens up with some driving).

tinymay

Just lookin... Is that a big 2 barrel on it now??

If it is, you will definitely benefit from a TPI or TBI in it's place.

Trinten

No, it's 4 barrel. I think it's Edlebrock (that's off the top of my head - I know my filter/screen/holder/thing is, but that doesn't mean the carb itself is). Part of the mileage issue is that it's currently mated up to my Muncie 4 speed, so at 65mph on the highway I'm just a little shy of 3000 RPM.

I'll be swapping in one of the 6 speed transmissions from the Pointiac G6, hopefully this summer, along with a gear-driven LSD for it.

I don't mind spending money for the "Right stuff" (though sometimes the best/right way isn't expensive), but what I dislike is doing things over again. So I'm trying to plan out the entire thing from top to bottom, so that once I do an upgrade, I know it'll stay there and not need to be removed/replaced anytime soon!

General engine question here - please pardon my ignorance on it, but what impact does a cam have on your intake? In the First group buy thread, one guy was saying that he couldn't use it because of his cam, and another guy was wondering if his cam would be an issue as well. I don't understand how one can cause a complication with the other.

tony_cogliandro

iTrader: (3)

you might outrun a cop car but you are not going to out run the helicopter.
never run. just take the stop, give them your license, and keep yoru mouth shut.
and im a fan of stock tpi. gm spent millions developing it and it works great for me. im not racing anyone or going to the strip but it has plenty to run the streets on. you can get them cheap, with everything you need, including wiring, computer, everything, for less than 500.00.

Trinten

Tony,

Sound advice, but I don't race it on the streets, I only race it at the track. However, I do like to be able to drive it on the streets.

I've seen alot of people talk about the GM TPI setups, but the ones I've seen are for the 305, and converting it over to the 350 is a bit iffy, especially depending on your heads (If I remember right, this was a 98 or 99 crate engine, so I think that should have the Vortech heads).

Any places you can recommend for buying the complete system, and what else I might need to change/do if I do have the vortech style heads?

And lastly, with the way my engine is orientated, I think I'm going to need to get an intake that has a side-opening, or try to use an U-elbow or something... any suggestions on what to do there? If it'd be best to get the GM setup and just a different intake housing that has the side-mount intake, or just pope a bend on the standard one?

I can provide more pic if you guys would like.

Thanks again!

tinymay

It does not get more complete than this guy on eBay...
http://cgi.ebay.com/ebaymotors/POLIS...1%7C240%3A1318

and you really need to know if you have Vortec heads because that will define what base is required.

Trinten

Oh, nice find!
Thank you for the link. I might get ahold of that guy and ask him how much extra it would be to rig up a MAF system!

The other drawback is that with the possible involvement of a turbo, and no set decisions on cam and pistons and such... having him make a burn and then possibly having to have to keep sending it back for returnes could be a pain...

Damn, decisions, decisions.... lol

But I appreciate you tracking down the option for me! I'm going to drop that guy a msg and see what he says.

Dale

iTrader: (12)

Sorry, kinda assumed you were doing the work yourself.

Clearance issues I was talking about was where the TB would stick under the vent on the pass side of the car. And while I "think" the upper intake can be rotated, I dont think the TB will clear the dizzy cap.

Now, about your current setup. I'm only getting about 15-16mpg intown on my TPI. And if your having to spray starter fluid in the carb to start it. You have some issues with your current setup. Going to FI may very well fix it, but it may be cheaper to just fix whats wrong with what you have, then going to something else.

Anyway, as I mentioned, TPI would look trick in that thing all polished up. But I think a TB may be easier to install. Have you looked around to see if anyone else has put a TPI into a fiero?

Trinten

Hey Dale,

I wish I could do the work myself. I don't have a garage, nor much in the way of tools beyond an extensive collection of the basics (I've got a massive socket set with all sorts of adapters and stuff... really comes in handy for the few things I can do).

Right now it's in the shop getting the suspension eyeballed and I asked them to pop the heads and find out if they're the newer vortech style or not.

I have been looking around and asking questions on Pennocks Fiero Forum as well - however alot of them actually say "Go to Thirdgen and read up!" lol

Not to mention I'm having a tough time finding someone who has done what I'm looking to do - that is the TPI with the MAF. And sadly, most of the threads over there that talk about TPI swaps get sidetracked with alot of people going "Do a TBI instead!" and going into details why, instead of just helping the guy out with what he wants to do (or just moving on).

So basically I need to do all the planning and research, buy all the stuff, and if it's things I can get done over the course of a weekend with my ton-o-handtools, then I'll do it myself... but if it involves have to do any heavy modification to the parts I get or to my block or anything... I'll have to take it up to my mechanic and say "Here's my stuff, install it." lol

Dale

iTrader: (12)

Finding out if they are vortecs is easy. Does the intake manifold have 6 bolts per side, or 4? Can also pop the valve cover and find the casting number. (edit, I can see right now you do have newer vortec heads)

Reason on the maf system, the MAFs in these are not all that good(newer cars are MUCH better), and its sometimes difficult to put in the air intake. Thats why MAP systems are easier for the custom setups. You can do it with either system, dont let it be your deciding factor.

I think your biggest problem will be clearance on the pass side. If you need measurements on anything, starting monday (1-5) I will be working on my car hopefully daily and can get you measurements off the intake if you want to measure around.

86White_T/A305

I for one have seen many Fiero TPI swaps making very good power,streetable,decent on gas,and naturally aspirated.The ones Ive seen were mostly speed density due to not having room for a maf setup.The advantage of speed density is that you can fab your own intake tube where ever you need it,slap a filter on and call it a day.

In my opinion I think if you build the motor up a lil with some basic mods,heads,cam,exhaust with Tpi.You will be very satisfied making just around 300hp in that car will be a rocket.

I myself converted a carb 350sbc to TPI with speed density using the kit on ebay which included the harness,ecm,sensors.The tpi itself i bought seperatly.Its fairly easy to install ..the install guide was well layed out too with pics and wiring diagrams.When you originally order the kit they will ask you what your setup is regarding motor specs like if your auto or stick,stock cam,cruise control,emissions equipment or not and then make a proper chip fully tuned.

Aside from that the only other parts you will need to go from carb to tpi is a tpi fuel pump,small cap distributor,injectors,proper length throttle cable and tranny kickdown cable if auto.. for tpi,maybe a diff water neck depending on location of rad hoses on that car,alot of patience,and spare change for nickel and dime parts you may encounter.Dont let this intimidate you.Take your time and it will get done right,there is plenty of info here to assist you if you look up threads regarding carb to tpi swaps.Start there.I did this in a matter of 2 days on my first try and im no mechanic.

Ive now swapped in a beater motor in my transam to build the original up quite a bit more and I know the car inside out and understand how things work alot better.Some pre tips for you if you go this route.I had the lower tpi intake base drilled for new and old style heads so that I wont have to worry about it being vortecs or not,ask as many questions you can think of,label or tag all the parts n bolts that you buy or take off the motor.

Once you have a running,tuned tpi 350.Then worry about if you still want a turbo...I thought I wanted one aswell untill I realised what I can still squeeze from it with bolt on mods.Sorry for the long post but it was needed to be said

Good luck.
Regi

Trinten

Hey Dale and Regi,

Thanks for the posts. I had actually tried to post a reply after Dales originally... but for some reason it did not show up. Anyhow -

My reason for the MAF route (and this could be totally wrong, please feel free to point out mistakes in my thinking), is that the computer can more accurately/efficiently monitor air/fuel, instead of doing more "guesswork" based on readings from the O2 sensors, and that the programming/monitoring options for tuning become more advanced with a MAF. Again, I could be way off.

*update here* Another guy on another board that I'm getting some info from just gave me his explanation for pro-speed density versus MAF. He said that basically GM never did a very good job at integrating the MAF system, and coupled with some of the airflow restrictions in other parts of the system it makes the Speed Density a better choice with GM engines. Opinions on this would be appreciated! If I can get some more sound reasoning like what Regi and this other individual is giving me, I might go with that system intead. *end update*

Since Dale was kind enough to point out that I have the vortech style heads (Thanks!!) I can work on planning the internal upgrades. I like things to last, and if parts do need to be replaced, for it to be done so easily, but I also like efficiency (hence getting rid of the plain carb). That being said, and since I've got the turbo, I figured I'd plan to incoporate it. The reason for the turbo is to help push enough air through at higher RPMs.

On the point of the MAF - I've *heard* that there are "reverse intakes" out there, so the intake would be on the driver side, but if those do not exist, I can get one of those "side intakes" like First makes, and then use an elbow to give me the room to hook up my MAF, which will also be in the direction my turbo is going to be mounted anyway (driver side of the compartment, some good room there), so it works out there.

So with all this in mind, my internals will include forged rods, pistons, and probably a cam from Compcams, since they'll help you spec one out for your application when you tell them all the stuff you've got. I feel the forged stuff is a necessity in ANY kind of boosted environment. I'm paranoid that way.

The hard part at this point (which I hope to solve this weekend) is find out if the turbo I have is adequate for my engine, and then figuring out what kind of pistons to get to work well with any other stuff that gets changed.

I'm guessing I'll need to decide on pistons last? Since the cam will affect how the pistons move? What order do I settle on parts? Cam, lower intake, pistons? In order to prevent anything from smashing into anything else.

So if you guys could help me plan out what I need to buy at this point, I would be really appreciative. And if you guys are ever in North Carolina, drop me a line!

86White_T/A305

Ok based on your update Ill ask this simple question that will greatly tell us what to recommend before you start buying parts at all regarding tpi or any other form of intake.

What are your goals for the car/motor...and what is your budget?Anything can be done..but be prepared to make your wallet cry lol.

I wont touch the subject of whats better..SD vs Maf.In my opinion it depends on setup which one will be more beneficial to you.I choose SD because I didnt want an air restriction for limit power once im done my build for a 383 holley stealth ram using the tpi ecm.Tuning wise maf is more forgiving in its ability to adapt to mods such as heads,cam,bigger intake where as speed density must be more finely tuned for max potential.

Ill point out to you that with stock tpi your limiting your powerband already to about 4500-5000rpm..after that a tpi just flow enough for high rpms but will produce more *** whooping torque than you can imagine lol.Using a turbo..your best bet is to post on the power adders board and find the specs on the turbo.See what those guys recommend if its within your goals.Building for boost is going to require alot more attention to detail than I think your ready for.Understand that if your set on a boosted 350 with efi...learn about tuning because it will only greatly wake a motor up under boost.

Trinten

Hey Regi!

Thanks again for posting and helping me out.

To answer your questions, based on my knowledge from guys doing build-ups on other cars (don't want to start any flame wars, so I'll leave it at that), I'm estimating that my budget on the engine is going to be a total of 4-6 thousand. That's between the TPI setup, tunable ECM, cam, and other forged interals, plus odds and ends. That does NOT include the costs of getting my turbo in place - assuming it's the right one to use (I will be finding out hopefully this weekend on that, if not, I'll sell it and get one that *is*).

My thoughts behind the turbo is that alot of what I've read on the various types of air intake is that at the upper RPM range it's hard to feed the engine enough air, so I figured a turbo is the most efficient way to help relieve that problem.

Ah Goals - to be honest, I don't have any set HP I'd like to achieve. What I *DO* want is a car that I can drive around town (not daily driver though), and take to the track and have fun with. I'd like to accomplish this as efficiently as possible - IE, find "the point of dimishing returns" in expense vs. performance/efficiency and stop there.

Horsepower TV did a show on the SBC 350 about a year ago, maybe less, and they invested about 3200 dollars into their naturally aspirated setup and had it pushing out around 400 HP. This engine was Fuel Injected though, IIRC. I have the specs of what they installed at home, I'll be happy to post it.

I figure if I start with what they used (or at least what is applicable to my engine), and just get a cam that is made to support my turbo, then I should be golden.

I do have the book "Maxium Boost" on order, alot of what I read said that it is basically the turbo-bible. I'm hoping that holds up to be true!

As I said, I'll post that upgrade list tonight, and then answer any other questions I can, and then hopefully you guys will be able to help me spot any bugs or bad ideas and get me through the planning stage!

Oh! For what it's worth to mention now, I currently have a manual 4 speed muncie. One of my upgrades will be to put in the 6 speed from the Pontiac G6s, mainly because it's one of the few transmissions that have a gear-driven LSD out there. I really don't want to go the clutch-pack LSD route.

Additional upgrades will include better brakes, and maybe some suspension work (I am Not lowering it though. It's low enough!). After that... just a fresh coat of paint.

Dale

iTrader: (12)

I agree and X2 on Regi on the maf/map aspect. As well the learn to tune the pcm. Even if you dont turbo, I'd suggest you learn.

I have zero turbo experience, so I have no comments on that.

Again, if you want measurements, let me know and I will get them for you.

Trinten

Hey Dale!

Thanks, anything that will help with the planning would be greately appreciated, so if you could take those measurements - any you think would be pertinent, I'd be thankful.

Seems we posted just on top of each other, not sure if you saw my long-mega-post just above yours or not.

Trinten

Hey guys, here are the specs/parts I mentioned earlier that were used that I was considering using myself. I *think* the only thing I'll need to change is the cam to support the turbo - and of course the carb-related stuff. What do you guys think?

(Cut and paste from their website/article on this episode starts here)
we added a street package consisting of a GM Performance Parts dual plane intake and a 600 cfm Holley standard 4160 four barrel. This bolt-on combination raised performance throughout the curve delivering peak power of 306.3 horses @ 5300 rpm (16.3 hp +) and peak torque of 339.5 pound feet of torque @ 3800 rpm (13.5 lb/ft +). With this particular combination costing $559.87, each extra pony cost us $34 bucks.
PACKAGE INSTALLED
Combination installed was sourced from Summit Racing Equipment. It includes the following components:
1) GM Performance Parts aluminum intake
NAL-10185063
2) Holley Street Avenger 600 cfm four barrel carb
HLY-0-81851S
The combination is available as package
SUM-CRTM1 price $559.87


For the second round of our small block Chevy testing, we installed a parts combination that upgrades our GMPP 290 hp 350 dyno mule into a late-model Vortec style small block. This package includes Edelbrock's new Top End Kit with 170cc E-Tec aluminum heads, Performer RPM Air Gap dual-plane intake, Edelbrock hydraulic roller cam and all required fastners and gaskets. To that we added new hydraulic roller tappets from Crane, shorter length pushrods from Summit Racing and a set of Summit 1.6 ratio roller rocker arms. We topped it all off with an Edelbrock "Thunder Series" AVS carburetor. This parts combination raised performance throughout the curve delivering a peak 411.9 HP @ 5800 rpm (121.9 HP gain) and maximum torque of 419.8 lb/ft @ 4500 rpm (93.8 lb/ft gain). The cost of this particular combination is $2770.75 meaning each additional pony cost us approximately $54 bucks.
PACKAGE INSTALLED
The part combination installed was sourced from Summit Racing Equipment. It includes the following components:

Edelbrock Top End Kit
EDL – 2099
Edelbrock AVS 800 cfm carb
EDL – 1813
Crane hydraulic roller lifters
CRN – 11532-16
Summit shorter push rods
SUM – 1457200
Summit 1.6 roller rocker arms
SUM – G6920B
The combination is available as package
SUM – CBB2 price $2770.75

Trinten

Well I finally found out more about the turbocharger I have. Unfortunately it's too small, Garrett lists it for only being recommended for vehicles up to 3.0L.

On the other hand though, I had started reading up on Garretts site, and I think this is the one I'll want to go with - GT4088R 751470.

I noticed that with the next few models on the site, the 751470-2 -3 and -4 the only difference in them is the Turbine A/R, going from .85 to 1.19. How does that impact the performance of the unit?

I mean I understand it's talking about pushing more air, but the listed horsepower range doesn't change - or is it that way because there are two ranges, the one for the engine size and one for the horsepower? So for a 5.7L it'd need one of the higher flow units to make "x-horsepower" than it would for a smaller unit?

Here's a link to the units that Garrett is making:
http://www.turbobygarrett.com/turbob...ison_sheet.htm

Someone else also suggested a unit from the Borg Warner s400 series... what do you guys think of those?

Or should I start a new thread in the turbo section on this? lol

Thanks guys!

BMXarkid911

I have a 88 formula that I got from a buddy with no engine and im wondering what I should do since its tpi and im having trouble finding a rebuilt tpi. I have the whole tpi sytem from the old engine just wondering what else I need if i get a tbi and put the tpi system ontop? sensors and such?

rgarcia63

Should bolt right up.
My TPI is on top of a pre 80s non-roller block.

bratkabruh

Where would I find an entire tpi setup for around $500?

Tuned Performance

iTrader: (92)

This is a very old post, if you need a 90-92 camaro tpi Harness send me a pm. I also have the ecm.
posting in the wanted classifieds and looking on eBay for a complete tpi.