https://www.thirdgen.org/techbb2/sho...38#post1616838

 

ok, and why should i switch?

seems like alot of time, money, and effort, for possibly zero, or a negative gain.

 

Thats up to you.

Some of us like the MPFI and the '730 ecm, especially for tuning. Not that '746 is bad, I've tinkered with it. I think jprevost has done lots of work with the '746. But for folks wanting MPFI, or modified TBI (mpfi intake, and a TBI throttle body with injectors removed - i.e, holly, edelbrock) the '730 is the way to go.

-- Joe

 

Each system has its own advantage and disadvantage. I plan on converting to TPI soon myself...

 

congrats, knock yourself out, my question, and the only reason i replied, is what is this doing in the TBI forum? i am all for posting, doing mods, chaning things, inovation. but this has nothing to do with TBI, i think it would be better suited in the ECM forum or the TPI forum.

 

It's geared twords TBI guys (whom believe it or not hang out in the TBI forum), who are considering switching to MPFI.

Obviously once your running the '730 ECM, you can run HSR, victor efi, etc. Not just stock GM TPI.



-- Joe

 

if you are going to all that effort, why bother with the 730? the 749 is a better system than the 730 is. and then if you are really seroius, you are ready for a supercharger

 

The '730 and '749 is the same thing, with the exceptions of an additional injector driver in the '749. You can run $8D in either ecm, and same with $58.

If your refering to code, $58 is good on a boosted app. $8D better for N/A though.

$58 also has some issues, like it can't control the air divert solenoids, or EGR so its not really emissions compatible.

-- Joe

 

Please explain into more detail in the thread above where the die-hard TBI guys won't flame you to death. You should've known how badly you would have gotten flamed. I've already begun collecting parts for a TPI swap, but the cost was outrageous...the Vortec manifold and the wiring harness were my two hold ups because they were the most expensive. I may resume my project if you can dumb this down for me, its hard for me to imagine this from reading it...its seemingly too good to be true.

 

I don't really care. If someone wants to flame me, it's their own time wasted. If my post helps people, then I've done something good. What good does flaming do?

If you have to run aftermarket anyway because of vortec heads, you might want to look into either a converted CARB intake, or HSR modified, or something along those lines. Noone ever claimed the stock TPI design was "wonderful" just that the '730 ecm in conjunction with a MPFI setup is really nice.

The wiring is straight forward. I talked to Jim at www.jimsperformance.com, and he said he's been converting TBI harnesses over to TPI for years.

 

i completely agree, at least step up to a superam, if you are already buying a vortec base.

 

There is no short runner system for Vortec heads, to my knowledge.

How in the hell would I adapt the superram to the vortec base or HSR? No way in hell could you adapt the HSR to a vortec TPI base...The SD Vortec tpi base is the same thing as the stock one except...it fits...vortec heads.


Carbueration is out of the question...I'll stick with TBI before I step back in time. I hate carbs, yes I know its an easy and cheap fix to all my problems, but I hate carbs...more than TBI. I do not want it..I want fuel injection.

If you convert the TBI to TPI wiring harnes, I've read it takes like 2 weeks for them to do it...How is an end user supposed to do this in 2.5 hours?

So do I have to rip out the engine harness or...not? If I have to rip out the engine harness, I might as well get a TPI harness to begin with.

 

the superram runners attach to the manifold exactly the same as TPI runners, then the plenum attaches to those runners. it WILL work to get the superram runners/plenum and use them with the SDPC vortec base.

From LPE

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

 

and that superram is better than getting some SLP runners and using a LT system?

Where can I buy, Jegs?

 

Vortech base, superram runners and top. All the superam is; is a plenum and runner package. The baseplate is the same dimensions.

You can adapt a HSR to work on vortec heads, if thats your desire.

I said "carb style intake" I.e, victor EFI, accel powe-ram, and so on. Looks kinda like a TBI intake, except its multiport.


If it takes 2 weeks to repin 3 connectors, and extend a few wires then there is a problem somewhere.. It took me UNDER AN HOUR to repin from 1227165 to 1227730 which is the same amount of wires as 1227746 to 1227730. I then spent about 20 minutes under the hood, removing maf sensor, wiring a map, removing esc, jumpering it to the knock. Then about 10 minutes replacing the knock sensor.

We'll spend more time talking about this on the board, then it actually takes to do the conversion..

-- Joe

 

i think it is, i am not a fan of the LTR's when you start putting in a larger cam that can make power about 4500-5k, the tuned long tube runners start to work against you. well the pulse wave tuning creates good torque at about 3500 rpm, above that it works against itself. the supram gives you a few benifits. 1) is the shortened runners, that helps make power above where a stock TPI system dies off. 2) larger plenum. 3) more airflow, it will plain and simple flow more air than TPI. not much explantion needed.


i don't htink jegs or summit carry LPE parts, you could try to call, i think you will have to get it from accell/LPE, i bet other venders sell it, TPIS might, thunderracing might, you will have to look around. being that i am TBI now, and have no plans to switch i have never really looked into where to buy a superram.

 

On my heavily modifed 355, from stock TPI to SLP runners, ported plenum, edelbrock baseplate I gained like 1 tenth.

On tpi_roc's car, from a aftermarket TPI setup to LT1 I think he gained like almost a second. (on a modified car)

The Victor EFI setups are rated for like 550hp.

Superram is nice, but I'd go with a Victor EFI, Lt1, or Miniram. I don't think Superram is worth the money.

I just wanna add.. If your not running vortec heads, I don't really remember you getting them. They're an OK head for a lot of apps, but they don't flow as much as people think. They have really nice designed ports and all, and are good for prolly around 340-350hp.

I'd go with an AFR-190 or equal if you were building a new motor.

If you allready have vortec heads, you might be able to use a vortec truck manifold, if the injectors can be made to work.


-- Joe

 

Hi, I'm Fred and I have the Vortec 350 H.O. and all I want to do is flow 600cfm so I can get decently close to this motor's 330hp/380tq ratings that GM gets from a 600cfm carb. I have been terribly dissappointed with TBI and I think its ugly too because it looks like a carb.



Ok, not on a smart *** note, like I said before, I WISH I had gone with the zz4 crate motor and gotten the regular heads, as I would already have the Holley stealth ram.

I think what I'll do for RIGHT now, is just buy some 89-92 runners from the yard and be happy to get it working, then save for the superram upgrade later...

Thank you for this enlightenment, this has made the swap a TON easier.

 

Superram plenum and runners, new from jegs is 780 dollars + shipping. Not for 19lb-ft of torque...HAHA

I'll be happy with my choked down 250hp (maybe) or whatever TPI can give me for right now. I like seat of the pants feeling, I like it a lot...screw above 4000rpm, I'm not dragging with this thing every day anyway.

 

Superram is wicked expencive, but to be fair that 19hp is on a stock L98 motor.

If your motor is cammed to rev 3200-6500, you're gonna see higher improvements. Your combo needs to match.

-- Joe

 

...

 

If you want the HSR so bad why don't you look into modifying it for the vortecs like they suggested?

I've never heard anyone change a form of induction because it "looks ugly" sounds like your mind isn't really set on the best performance for your engine.

 

In response to your jack *** reply, here is mine. I don't want HSR. I'm not a machinist. So why don't you put your opinions on a tape and I'll play it back when I care. And what use does this add to the discussion? You obviously do not plan to go MPFI...

I drive this car daily, if I run a 14.5 I'm happy. so why don't you worry more about your car instead of mine?

 

Ok, why don't you take it easy with your harda** replies. If you want MPFI post on the TPI board and they'll be able to help you more. This post does not belong on this board. Sorry if people on here get offended, because its people like you who give TBI a bad name.

You couldn't have honestly thought that throwing that much of a different engine in that car and running a 305 balancer and setting timing by ear, with the stock tune and basically everything else stock that it would run right? You have serious problems with your engine setup, that is why you're running so horribly. People have tried to help you on here but you've been too stubborn to take advice and fix what needs to be fixed before you swap induction.

This is not trying to upset you or whatever you think, but you need to look at this logically. If you swap to TPI or something you're just going to be more disappointed when you drop all that money and it still doesn't run right. I would say straighten everything else out on the engine first and then worry about MPFI.

This is not a flame or trying to provoke another response like that, just take the advice you've gotten on this board and fix what needs to be fixed first and I think you'll be a lot happier then by all means swap to a superram or TPI and you may pickup some power.

 

I agree... No matter what you have on top its going to need to be tuned, simple as that. The tbi that you so hate would have been able to meet that engines needs. With a 670/bb tbi with the proper size injectors and a good dual plane intake with a siamesed plenum or possibly a single plane intake your air/fuel needs would have been met. The stock calibration is probably one of your biggest problems. The stock calibration only works for an unmolested L03 305 and nothing else. The tpi's calibration will probably get you a little closer but it will still need tuning just like the tbi did. With tuning i suspect that you could get the tbi to run jsut fine and drop your quarter mile times to very low 14's or high/mid 13's with some attention to detail.

 

He needs to get into prom tuning.

He's running vortec heads, so what a vortec baseplate and a TBI adapter?


-- Joe

 

I'm almost positive GM makes a vortec tbi specific intake. He could use that or any other carb intake made for vortecs and then just a TBI adaptor plate.

 

I have the GMPP Vortec TBI manifold.

For the record, so you people can stop flaming me...or sending jackass replies. Sorry the waste of timers that are unrelated to the thread really **** me off...The one guy who just posted .... and your jackass reply Bronyraur **** me off..As I posted above if you hadn't noticed,I said he should not have posted in here...The TPI guys seem to flame a LOT less than the TBI guys do..I guess its all the harassment you take or something...or you have outside problems. His (anstheses) response was he did not care and it might interest TBI people that want to switch to MPFI...which must be at least say...5 people? Their certainly wouldn't be a tech article would there?

For another record Please stop telling me TBI is better...I know it has a a better value as far as gains go. I don't care. Its my car, its my money, I'm chosing this. End of story. I'm begging you, stop with your harsh replies and stories of how TBI is better. PM with your addresses and I'll mail you some extra sony cassettes and I might play them back one day when I care. I thought about upgrading and keeping TBI, but with this post, it has changed my mind back. Again, my car, my money.

1)I've always wanted TPI. I made a huge mistake 2 years ago when buying this car when I was barely 17. I bought a 305 and TBI . At the time, I thought, "wow its a V8 it must be fast." How horribly, terribly wrong I was.

2)The 350 balancer is on order as well as the walbro 255lph fuel pump. I also have the Zexel-torsen posi and 3.42 richmond gears sitting in my garage. I plan on installing all 4 items BEFORE I swap to TPI. I'm trying to collect all my parts before I do this.

3)I have taken your advice, but I'm not made out of infinite money. I do make enough to play with my car though, but not to go out and fix every other problem that goes wrong with this car. I realize that its an old car and things are gonna break along the way or not work right...I swear I must have a 1-2000 dollar list of imperfections suspension, cosmetics wrong with my car or that I would like upgraded.

4)Just you ALL know, I do plan on getting on the balancer and timing it correctly BEFORE the swap. Chip tuning and further TBI, upgrades, absolutely not. I'm not spending another dime on when I have TPI stuff on order and the TPI setup sitting in my garage.

So please let me know, Bronyraur, why your little "I've never heard of anyone changing induction systems because of looks." comment was warranted? I'm sorry, Last time I checked it was my car and my money. So who REALLY had the jack *** reply? So when I give a little of it back, you can't take it? If you want to continue this, just PM me and we'll settle this.

 

I'm not going to waste my time PM'ing you. You obviously are too immature and have no humility at all to take advice on how to get your engine running well and have to sit there thinking oh no somebody gave me a "jackass" reply. I find it funny that you're getting so upset about this, I specifically said it was not a flame, so take it easy. Honestly I think you should swap to TBI, you don't have the patience to work with what you've got and my comment about changing induction because of looks is directly quoting you. How does that require explaining?

I've been on these boards for a while and I've never got into it with anybody like that. You need to understand that you're not getting flamed but when you reply to other peoples questions on these boards saying TBI is bad because it didn't work on your combo that's when guys on here get upset. It didn't work for you because you didn't make it work. Now you're done with it so swap to TPI and go to the TPI board, there's no need to respond to questions on this board anymore.

 

Yes master.

 

i guess i'll be the only one to say it..

thanks anesthes... ive just about given up on getting a SD harness at a decient price....

im probly going to run the $58 on a 730 and mod my TBI harness to work....

 

He is right. Also, Thank you anesthes. I started yard hunting today for the parts. Your information will save me a great amount of time and money and has inspired me to continue with the conversion.

 

Your welcome, and to run $58 you just need to swap the injector and IAC wires around. Once you get it to '730 to run $8D, just do the $58 conversion.

Also, you don't need a '749 ECM to run $58. It works fine in a '730.

Good luck!

Your welcome as well. Two things I wanna point out though.

1) You can send your intake to a shop and have it modified for MPFI
2) You can run your stock TB, or a larger one with the injectors removed. I thik if the intake is ported, MPFI rails are added it will make more power than the stock GM intake. Might cost you less than finding the parts to boot.
3) 305 and 350 is the same harmonic balancer. What matters is the diameter, and if the engine is internal or external balance (like a 400). However, CAT power engine products sells a fluid damper thats SFI approved. You can get them on ebay for 100.00 + shipping.

Take care

-- Joe

 

Hey guys, just wanted 2 mention a few things:

1) Anesthes, I think having a manifold sent out to be modified for mpfi might not be as economical as just buying one, would it?

2) Someone earlier mentioned that TBI can meet the fuel/air needs of the motor in question, personally, I think this is a really misleading statement so I just want 2 throw my .02 in.

A 670 holley TBI will only flow to about 4500 rpm on a 350 cid motor, not by any means high enough to support anything more than a bone-stock camshaft. However, a TPI setup is no better, they're restrictive and stock, not a whole lot better than TBI (probably marginally b/c their throttle bores are larger initially).

Go with one of the ram multi-port systems. Thats the only way to go other than LT1 or something (thats the only stock system other than a carb I'd say is worth trying).

Ty

 

I think its been proven that a 670 TBI properly tuned and setup can support more than just a bone stock cammed 350. Check out some setups guys are running on this board. The biggest is r90camarors's 383 with a Holley 670, he says he should be in the low 12's I think now. Also, jon prevost and swerve-driver are running vortec heaced 350's pulling mid-high 13's I believe.

 

Holley 670 is factory on Mercruiser 260hp boat engines.

-- Joe

 

You guys are 1/2 right - my TBI 350 is 270hp (dynoed) and thats with the holley, but my point stands - the peak is at about 4500 (depending upon volumetric efficiency of the motor). As far as the 383 TBI motor, I'd be convinced with dyno sheets or time slips - there's a lot more to a combo than just the motor, so someone really pushing a TBI setup will definitely run 12s, but I bet he'd run 11s with a 850 demon (or at least he'd run faster is all).

Ty

 

This is one of the stupidest posts I have read in a long time.

 

also, tpi is factory on 245 hp car engines, what the hell does this prove? nothing. This post was pointless. I am really sick of all the tbi vs tpi crap lately. Get over it people. Who cares.

 

Who cares? Those who want to learn more about their cars. Those who want to go faster. Nobody forced you to read anything.

-- Joe

 

I'm with anesthes. We're just bouncing ideas back and forth about the systems capabilities, s'all. 25THRS - if you think its so stupid, don't read it. Everyone on these boards loves flaming others and throwing accusations around but nobody ever likes talking facts - which is what we're trying to do. Grow up. And yes, that was a flame.

Ty

 

*looks around*


ITS JUST A FUGGIN WAY TO GET FUEL INTO THE MOTOR PEOPLE!


as far as air.... they both suck(stock). its just easier to make TPI suck less.:lala:

 

ugh, i quit.

 

no, it is a matter of having more aftermarket parts that are 'TPI specific' but they all cost way more than the TBI options.

For every 12 second wonder TPI car people point out, i know two who have spent the money, done everything right, running 350ci or larger engines, have the HSR, miniram, or whatever and still are in the 13's. Just like with TBI.

I am still of the opinion, that trying to convince people to undertake a swap like this IF THE ARE ALREADY UNHAPPY WITH HOW THEY RUN, is stupid. if you have problems with the motor, or tuning issues, going from one for of MAP injection to another is not going to fix anything. argue all you guys want, but TBI is cheaper to get you into the low 13 sec, probably high 12 sec range. beyond that, it is still cheaper, by the time you talk about getting a miniram, new injectors, ect to support low 12's and beyond, you can get a 900cfm TBI unit, and that will easily support 500hp.

 

double post.

 

to be honest.... i dont really care. i'll help someone fix either one, whatever one they have.


i AM kinda pissed that you guys are even bothering debating it.

im cheap. i have boost. i can get 8 bigass injectors and make it work..... but i cant find a harness... thats what this stupid threads about...


and you guys have to go.. duuuur why!? bla bla bla...

i dont give a **** what you or someone can or cant do with either system. now, cant we just keep it on the topic of swapping a TBI harness to TPI, or just not post here?
i dont think thats alot to ask.... i mean, i already have to scroll allthe way to the bottom of this stuff to see if anyone has anything meaningful to the topic to add.


edited out the part that i dont even want to start another debate about.

 

because i am trying to save some poor soul who doesn't need it, from dropping his/her hard earned money into a TPI system + computer, when it is NOT GOING TO GIVE THEM ANYTHING, but possibly more headaches. you guys make it sound like TPI is the end-all solution for these cars. there is another thread on this already, why not use that one for the couple of people that this might help, or might want to do it, and not waiste space in the TBI forum. now we have this post, and people who are not happy with how their car runs, and are thinking...hmmm should i drop the money to switch? when after they switch they are still going to be unhappy with how it runs, and now they are $500 or more poorer.

 

i dont need it.

i need a affordable multipoint EFI solution.

a $15 ECM and some junkyard wiring to complement my current TBI sounds great to me..... not to insult you or your way of thinking, but for the price of one holley TBI and a $100 carbed intake, im going to have a running TPI BASED multipoint injection system.
the only "tpi" parts are the thottlebody, throttlecables, and fuel rails, and stock FPR... the 730 could be out of any GM car...


im not making TPI sound like anysolution... the "system" is crap... its just the fact that they have a superior and fully hacked ECM is all im after.

TBI isnt all that, nore is it the best bang for the buck, nore is it the solution to my or everyones problems.

rather then being general, go address specific things or somthing.. heh, i respect your work and your opinion on that, and im well aware of the facts, but theres no "tuned port" involved here.


should we just go get a mod and change the name from 747 to 730 ECM wiring help?

 

Ermm.. So its better to spend money on an aftermarket TBI setup, than spend money on an aftermarket MPFI setup?

How many guys in the diy_prom board are running 500hp '746 setups? How many are running 500hp '165 or '730 setups?

If your gonna spend $500-800.00 upgrading the intake (be it a MPFI intake and throttle body, or TBI intake) than why not spend the extra hour repinning your harness to run good software?

My intention here wasn't to bash TBI, or to get people to convert. I just wanted to help out, and I think I did that. If you want to run a 900cfm TBI setup, than I'm happy for you. Go for it! But I know on my car I like the MPFI stuff, I like the software in the ECM, I like the 8192 baud scanner and datalogger, I like all the utilities available for assisting the tune, I like the hacks on the 'net for going above and beyond, and most of all I like the fact that there is a ton of guys out there to bounce ideas off of.

To get your TBI setup to run 500 hp, you'll need a 900cfm throttle body, a decent dual-plane intake manifold, an upgraded fuel pump, and some very very large TBI injectors. I'm not even sure
what you'd have to run for a fuel rail pressure. IS that where you'd rather spend your money?

If you look at any aftermarket setup, the MPFI kits are rated to much higher HP than the TBI kits. There is plenty of reasons.

Something that I would consider on a TBI setup however, is using an edelbrock conversion intake. If you can purchase the intake + fuel rails seperately, you can then use your 900CFM TBI. You get the benefits of even air distribution with a center mounted throttle body (IMO TBI's only pro over TPI), and the benefits of MPFI.

-- Joe

 

Yes and you participated. I wish a moderator would have just locked the post down and made it a stickey somewhere on this site with his information...so all you guys can shutup and worry about YOUR OWN CARS AND YOUR OWN MONEY! If we have money to burn on this, IT IS OUR OWN BUSINESS! WHO'S FAULT IS IT IF WE GO DOWN THE WRONG PATH? OURS!! NOT YOURS!