i am alittle new to this whole forum thing to bear with me but i have a few questions. i have a 88 z28 camaro 305cc TBI 700R4 and very soon i will be putting a 350 with some engine work and vortec heads into it w/my grandfather. i can only do one thing at a time but one thing i plan on doing is working on the induction side of the engine but do to funds i can only afford to stick with the stock tbi + intake manifold for now. it doesnt have the best response but its something i want (response). i've talked to many poeple asking what i should do. one guy of which was a GM world technician (i'm not sure of the technical name for that position). i asked him what i could do to my "intake" to improve its performance and response. he said that an alluminum intake manifold is always good and he said that he often see's people put a 454 throttlebody on a 350 because of its bigger bore and bigger injectors it can deliver more fuel and air. and i'm sure that some computer tunning may be at hand also but i'm not sure what to tune or how to go about doing it. does anyone have any input?

 

first of all you have a (about) 5000cc engine, not a 305 one.
secondly is you need to be able to tune, if not, you are stepping backwards by modding this car to this extent.
third, id go with a nice single plane intake manifold...

 

GM Perfomance parts sells a TBI intake, try looking at summitracing.com or jegs.com

As far as the 454 TBI, you can adapt it to your stock system (the TPS connector has to be rigged) and you should get an adjustable fuel pressure regulator or mod the stock one so you aren't running excessively rich.

 

spend the next six months learning how to tune hands on. then consider the changes to motor. vice versa you could be potentially lost.

 

Howdy Concord, NC. Boone graduate here...

Listen to Ronny. Unless you are an old hand at the Chevy SBC, take the time to learn more about your engine and see what you can do on your own. Soon, you'll figure out the short list of things you should do based on the information you learn on your own as well as that from this forum.

Cheers,

~C

 

ok well i understand now that i may need to tune if i went this route but i spoke with this GM world master tech (again i dont know the "official" name for this position) again at my school (nascar technical institute) about his suggestion with the 454 throttle body on my 350. he has to be by far the smartest man about cars i've ever talked to (not to say anyone here is stupid, just stating his intellegence on the subject). i asked him what sensor upgrades and tuning would be required. he said that there shouldnt be much tuning needed, that the 305 computer should be able to operate it just fine cause its still telling the injectors to turn on and off no differently, just injecting more fuel then normal due to bigger injectors and it will be taking in more air due to the bigger 2" bore (i wont go with a 454 throttle body unless i had 2" bore intake manifold put on to compensate) and i wouldnt need any sensors replaced really but i guess the only people who would know FOR SURE would be people who have done it already. i guess if i decide to go this route i'll have to due some trial and error. but before i decide that this is maybe what i want to play with does anyone have any input or suggestions as to some other things i can do for a good highperformance intake with my tbi. or tell me what you have done to your car that has worked good with you to give me some more ideas. most of my friends have carbs. or tpi. i'm the only one with tbi i know personally.

 

"i will be putting a 350 with some engine work and vortec heads into it ""with the stock tbi + intake manifold for now"

did i hear that right?

 

yeah you heard that right and i wouldnt be putting the stock tbi + intake manifold if i had the money right now to get something better. i am extremely strapped for cash right now and i was wanting some advice on systems and components that work well for future reference. i fully understand that with the stock tbi/intakemanifold that my engine will not run nearlly at its full potential but i havent much of a choice due to money reasons so if anyone wants to share with me what they've done it would really help me in the future.

 

Stock intake manifold won't bolt up to Vortec heads. You'll need a new one no matter what.

 

do you know for sure? i'm not trying to second guess you but i was told that before but he didnt know for sure and i wouldnt know because this is my first engine swap. well aside from the fact that i'm gonna have to fork out even more money that i dont have, can i get somemore recomendations as to a new intake setup???...and what kind of intake manifold do you recommend since i have to get a new one now? anyone???

 

Vortech heads have diffrent port angles, and a diffrent bolt pattern for the intake. You intake will not bolt up.

Learn the computer side of things, you GM master tech may know plenty about chevy motors, but may not know the first thing about what a TBI computer is going to do with mods, ask him how many modified TBI cars he has dealt with. Do a search for the people in this thread who are telling you this. They are the people with some of the more modified TBI setups on these boards. They and myself are telling you this, because we have done this, we know how the computer will react to the changes.

As for intake, I would suggest a single plane carb intake, with adaptor and a 454 TBI unit, with the injectors that will match up to the HP level you are going for with your motor.

--John
(going for 12's with my TBI this year. ;-))

 

well since i've been posting on this site i've been surfing around on this site and i've learned alot about tbi and things i COULD do to my intake and throttle body. there is no doubt there are some very smart individuals here which is why i keep asking questions to better understand what would work well with my application.

"As for intake, I would suggest a single plane carb intake, with adaptor and a 454 TBI unit, with the injectors that will match up to the HP level you are going for with your motor."

first of all thanx for your input, it seems i have no choice but to get a new intake if i want to put my 350 in. you recommended a single plane carb intake with adapter. if i didnt ask anyone i would just go with an alluminum vortec tbi intake but u obviouslly would know what works better then i do so why should i go with that? what is the benifit of going with this setup? i read in another thread that a 454 throttle body and a holley 670 tbi unit work well with applications like mine. you recommended a 454 tbi but would one of these work better than the other? i was also told in this thread that i may need an adjustable fuel pressure regulator to keep from running rich. what kind should i get? i think this will be my last thread of questions to stop annoying those of you who are smacking me in the face with knowlege and i really appreciate everyone's help on the subject.

-my1st88camaro (NTI student, moorsville N.C.)

 

keep posting, that is how you learn. ;-) No one is annoyed.

The single plane is ideal, because for a few reason, the first being plenum volume, TBI likes a large plenum. it also allows you to draw air from both bores, by all cyls. this gets rather complex, so we will leave it at that.

670 and 454 throttle bodies are very similar, the 454 unit is much cheapers, as you can probably pick one up at scrap yard.

The real key will be in turning, adjustable fuel pressure regulator or not, the car will not run right with a vortec engine swap, unless you put in the time tuning the computer.

 

thanx alot, i know i'll have to tune the computer eventually but would it be possible to just switch out the computer with a 350 computer or a 454 computer to get it to run right or is there no way around this?

 

there is no way around it. neither the 350 computer of 454 computer come close to matching the motor you are putting in. My best advice is to start reading and tuning on your motor now, so when you do the swap you have some experiance messing with the computer and know what changes effect what.

 

You wouldn't even need an entirely new ECM, you'd only have to have a new chip burned for the existing one to compensate for the additional air and fuel....

 

well i guess i only really have one more question about this subject. i only have a short window of time to put my engine in which is coming up due to my busy schedule and work and i know i wont have the money right away to have it tuned once the engine is in so i'm wondering what are some effects the engine swap will have on my cars performance since it will be running on the stock throttle body? loss of hp? torgue? gas mileage? etc. and or will it damage anything? should i be concerned if i dont change the throttle body right away?

 

If you run really rich on a new motor, the rings may not seat right. and depending on the combo going in, and the chip being used, the car may not even run.

 

I'm the one he has been talking to about his car. I have the equipment to tune TBI cars and have tuned a bunch, but since I spent most of my time on TPI cars and have since moved up to LS1s, I sent him here to get more "accurate" information.

I told him to do as much research as possible before deciding what to do, so keep the good info coming!

 

lol haha hey GMTech. i hope you're not mad for me refering to you but i tried to keep your actual name anonymous out of respect. but yeah you were right about coming here i've already learned a lot about TBI withing the few days i've been posting. there are a lot of knowlegeable people here and everyone's been a big help. i have a pretty good idea as to what i'll do with my intake setup but its just a matter of time and money and i hope that nothing is really damaged during the period that i have the new engine in without some computer tuning. actually after surfing around this site i've come across tuning your own chips and it sounds like something i'd like to read more about and maybe sometime try on my own car. anyways thanx for everyones input and advice. i guess i can end this thread now...

 

Just to mention, the last TBI project I did was for a co-worker when I was at the dealer. He built a 350 w/ LT4 hot cam, vortec heads and the GMPP Vortec/TBI intake. He put it in his S-10. I cannot remember which TBI he used, but it ran suprisingly well before I did any tuning.

I used to frequent here quite a bit a long time ago, so many of the older members know me by name anyway. No need to be anonymous.

 

can we assume this is a second car for you? not a daily driver? if you are dependent upon it to get to school/work daily you may be disappointed as some days it may not happen. if you decide to mod it have a second car around to get you to church.

 

actually this is my everyday car. i understand this maybe a mistake but i'm a guy with lots of testosterone

aside from that i e-mailed a guy that custom tunes TBI chips and i told him i was considering a 454 or a holley 670. he said dont go with those that i should go with a throttle body on this website http://www.xtremefi.com/QA.htm and i was wondering what does everyone think about these throttle bodies?

 

I've heard some very promising things from many different people regarding that "horsepowerguy". If he really can bore out you're stock throttle body to 750-cfm, with or without sleeving it (for under $200.00), then I say go for it!

If you decide to go with him, then try and post some pics of the finished product. I'm curious to see, as is everybody else, I'm sure....

 

well on that link i dont think it says anywhere that you can send in your throttle body to have it bored. it just gives a link to ebay where you buy these throttle bodies already bored. and if what they say is true about their throttle bodies then they would be the way to go. especially since its just bolts on with no problem. well it will be a while before i do anything with my intake setup because i have to get my new motor in first but i think i may look into this some more. but if/when i do i'd be glad to take pictures of it and give my opinion of these throttle bodies to everyone so they can get one too...anyone else have an opinion on there throttle bodies on that link???

 

I used to frequent here quite a bit a long time ago, so many of the older members know me by name anyway. No need to be anonymous. [/B][/QUOTE]

Bernard, right? Last I recall, you were building tranny's, right?

Now you're getting paid to teach folks, too cool.

Don't you/didn't you run SEthirdgen?

Not sure if you remember, but you helped me out a few years ago with my mom's quad4.

Seems like it's been treating you well.

 

Sure you can. In fact, here's an e-mail that he sent me when I was contemplating my own throttle body getting worked on (although, not 750-cfm);

"We can bore your TBI unit to 50mm, and rebuild the throttle shaft for $169.99".

Thanks,

Tom Bishop
7000 Vallecito
Austin, Tx 78759

 

oh well i would ask how but i would probably just buy a new 350 throttle body instead of having my 305 throttle body bored out. when i have that done i'll probably get a new intake manifold also so i dont need to worry about sending it in. actually i'm putting my engine in july 5th 6th and 7th (with new trans too) so i'm hoping everything goes smoothly. after i get it in i'll let everyone know how it runs with the stock 305 throttle body. shortly after i should be getting it tuned so it should run better but we'll see.

 

besides occording to that website their "already bored" 350 throttle bodies flow better then a 454 so i guess if it will bolt on perfectly then it would be the way to go...

 

i would consider running it with the stock TB first. tune that first and then swap in the larger TB later after you are comfortable with your tuning efforts.

 

well i got the new engine in. it runs fairly decent but it could use some tuning. but i cant go driving it yet there are some things still wrong that need to be fixed.

 

Such as..........?

Also- I am not clear on what Throttle Body/Injector combo you have on the car right now.

Ronny had some good advice in his couple of posts as far as what order to do things in and the suggestion of using the stock Throttle Body prior to going for the bored out one from Tom Bishop.

I had work done to my TB by Tom with relatively good results. It is about half way down in my first post of this thread:
https://www.thirdgen.org/techbb2/sho...hreadid=307640

My previous set up was similar to yours. I wouldn't worry about the big TB until you understand tuning. I would look into running a stock TB with 350 injectors and get it running right using WinALDL (or similar) and burning some chips (or using Prominator).

I tuned my vortec TBI combo using the stock fuel pressure and 65# injectors. Never had a problem with fuel delivery. Air may have been restricted somewhat, but running 13.8s on that setup met my expectations.
I am expecting a little more out of the new setup.

Best-
S-D

Also- if you grandpop actually helped you with the swap as indicated in your original post- he is a cool dude! ~~

 

well as far as the problems it has a trans leak, an oil leak, and it over heats at a high rpm. i posted a thread in cooling about the temp. problem. but the oil leak i can fix its no biggy and the trans leak i can fix but dont have the means or equipment to do it. i'll probably just go to cottman transmissions and get it fixed and be done with it so thats no biggy. but if you want to help go to the cooling threads and look up my post and let me know what you think. as far as whats on there now it is the stock 305 intake and throttle body. its runs fairly well i was surprised. although from time to time a sensor of some sort varies the idle up and down and up and down and the check engine light came on. but i guess all this is to be expected.

 

Post up your SES codes!

https://www.thirdgen.org/techbb2/sho...ight+codes+get

The up & down idle might be the IAC on the Throttle Body.

What injectors are you running? The stock 305s?

S-D

 

That up and down idle is probably being caused by an air/fuel mixture that is way too lean.

 

yeah i'm running the stock 305 intake and throttle body...i only chose to do that due to money reasons. and you are probably right about the air fuel mixture...i'm hoping i will get to tune it soon before the a/f mixture does any damage. i'm going to have to get an exhaust soon though so i can let it breath. u can tell its being sufforcated alittle

 

i see you refer to TB's often in posts. but i dont see a Q? regarding injectors. consider running the stock TB's as is which may be inadequate but car should run decent up to WOT; mainatain the stock injectors but up fuel pressure a few lbs at a time and determine results. OR swap in some larger injectors with stock TBI/manifold and run 13-17 lbs and see how it responds. i would love to see a datalog(winALDL) or same with WB.

 

i dont know what you mean...

you know adjusting the fuel pressure doesnt sound like a bad idea. i talked to someone who might be tuning my car soon since he's done it before on a throttle body so i guess i'll do whatever will work best with his tuning but for the time being i guess the cheapest way to help its mixture would be to adjust the fuel pressure like you said. but i have every intention in the future to go with a bigger bore intake and throttle body with bigger injectors. but right now there are other things that i need to focus on the car now like getting a decent exhaust so the car can breathe, paint job, tires, rear brakes, diff, etc... atleast i finally got my engine in. anywho i'm on my way tomorrow to try and fix the overheating problem i hope. more details about that in a threat under cooling

 

i would install the larger injectors first. it will make the tuning efforts much easier. once you have the tuning understood the addition of the large TB's and subsequent retune will be easier to master. i made the mistake of doing all at once( heads, intake inj's, TB's, exhaust) and the tune was and still is very challanging.

 

i'll keep that in mind when it comes time for me to do some tuning