TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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So basically look for a '97 up truck ? Hmmm that might be difficult out here, once they arrived at the junkyards here they're already partially stripped, give it two days and everything else is gone.
So basically look for a '97 up truck ? Hmmm that might be difficult out here, once they arrived at the junkyards here they're already partially stripped, give it two days and everything else is gone.
(L31) 96-99 Chevrolet and GMC 1500 pick-up (Silverado & Sierra), Suburban; 96-00 Chevy and GMC 2500 and 3500 pick-up; 99-00 Cadillac Escalade and GMC Denali; 96-00 Tahoe and Yukon; 96-02 GMC and Chevy full size van
hey fast, i had an idea... it is possible to put hemi heads friom mopar onto the 350 block? would that decrease fuel economy while increasing performance?
I had the idea, but i wanted to know if it would hinder the build up that you outlined
Dodge Hemi heads will not fit on any Chev without some serious mods. You can get a hemi head for small blocks from an aftermarket supplier but I dont think that you would like the cost to much!! Not worth the money or time. A good set of aftermarket heads would get you much better performance along with a possible increase in mileage. Just my 2 bits
Fast, I checked and the 454 TBI fuel pressure regulator is discontinued.
Went to a local parts store today, and the only real difference I could see between the 350's regulator and the 454's is the size of the spring.
So........is it conceivable that just changing the spring will increase the fuel pressure to the 454's 30psi level?
When I took the regulator apart on my truck, it had a MONGO size spring in it. I had another throttle body with a more normal appearing spring in it, replace the King Kong spring with the normal one and have 15psi at idle. Did I mess up?
I'm really convinced this thing is starving for fuel, and that I need to raise the fuel pressure to crutch things til I get all my tuning stuff in.
so 1.5 years ago I got interesested in repalacing my stock 2x4 old style holleys on my 57 Tbird y block. I contacted customefi's for a harness and ebl modified computer. turn around time was to be 1-2 mos (I know, trusting can be stupid.) I built adaptor plates for the small holley bases to tbi. rebuilt the tbi's while I waited. the harness finally came but the base programming never came. I have been reading all of these posts and your build up is clearly the most organised discussion I have read. Total cubic inches in the small motor are 305. Mild stock cam 9.5/1 compression. I converted the distributor to a ford reluctor and pick up, took out the mechanical advance and am using a GM module. I sure could use some help with the programming but IT LOOKS AWSOME and will all hide under my stock air cleaner. I am a life long car guy and the electronics are great but getting this 2 TBI set up going has me at my wits end.
I'm going to use my 355 or my 383 , have both now for my 92 RS and was wanting to leave the TBI on it for the simple reason that it works great. Was wondering if there anyway to get some help on this build. I built my 92 Z but that is a whole different game and I went with a stealthram and love it. I have built big blocks small bolcks and 4 and 6 cyl engines but this is new to me. I have headers, 2400 stahl, new 355,383, aftermarket vortec heads that will accept the tbi intake, and a 350 tbi unit. I was also wondering if I use a aftermarket aluminum intake and tbi adapter plate if thats better than a stock or aftermarket tbi intake. My last question is if I can get by easy with just a chip or have to get a new ecm , or ? . Thank for any info, Les
Hey I have a 1993 Cadillac Fleetwood Brougham which has a 5.7 Litre 350 TBI....Its obviously old and runs like ****, hows a good way to make it haul *** but not too much *** :P I don't want to rebuild it but a bunch of bolt ons and things like exhaust would be good i guess, can anyone give me a few ideas of what to do whether it be adding a lot of performance stuff like fuel pumps, camshaft, etc.....thanks.
Alright, I read the intake manifolds section, but I'm not sure which would be better. The reason I ask this is because of the type of heads that I might go with. If I go with the Vortec heads, then obviosly the Vortec intake will be a good combo, but the Vortec heads are cast iron. I'm trying to shave a few pounds off the car while upgrading it.
What I am wondering is, what are some good or great aluminum heads for the LO3, that are reasonably priced? Then what would be a good intake manifold to complete the combo?
im still researching, but patriot freedom heads and tri-state heads are both aluminum and are around the 700 mark.
The patriots flow awsome over .500 lift. I think u get what you pay for tho, ive heard they arent completely "clean" as in they dont compair to the 1200+ cnc'd heads. But for the money sounds like a good deal. Ive never ran a set or have seen them in person just basing that off what ive been reading up. Im thinking about getting a set or splurging for some eddy's or somthing.
ok ive read this and im just wondering what would i have to do to ensure i dont get the (ae) as said by fast , im doing a 350 swap in my 91 rs it had the tbi ho set up. my new 350 has a 10.1 compression and am running a torker intake on it , it has the lo3 305 ported n polished heads and the cam is a 236 duration and int/ext and a 488 lift i think in not sure but it is a 488 lift. and i currently have a 91 tpi fuel pump in maybe from a v6. not is there any thing i need to worry about in the fuel systen about getting enough fuel to just lay on the gas. and im currently running the stock ecm
Old thread , but just to note i had a 97 c1500 automatic ext cab with 3.42 gears and dynoed 245 rwhp/317 rwtq with just a set of edelbrock headers ,dynomax 3 inch single exhaust and the flap removed from the TB blade no tuning. never went inside the engine.
Alright, I read the intake manifolds section, but I'm not sure which would be better. The reason I ask this is because of the type of heads that I might go with. If I go with the Vortec heads, then obviosly the Vortec intake will be a good combo, but the Vortec heads are cast iron. I'm trying to shave a few pounds off the car while upgrading it.
What I am wondering is, what are some good or great aluminum heads for the LO3, that are reasonably priced? Then what would be a good intake manifold to complete the combo?
Good cheap aluminum heads would be some aluminum L98 heads or look into patriot performance. Intake manifold is edelbrock 3704 for a direct bolt on, but if you want better then get a good carb intake manifold and then a TBI to carb adapter plate.
But if you want to go vortec then im not sure.
Hey fast if i were to run the setup you were talking about, with the L31 and the vortec tbi intake manifold, with the LT4 cam. Could i just upgrade my stock throttle body to the holley 670cfm? would that work, and if i bought that 670cfm doesnt it already come with the injectors?
Hey fast if i were to run the setup you were talking about, with the L31 and the vortec tbi intake manifold, with the LT4 cam. Could i just upgrade my stock throttle body to the holley 670cfm? would that work, and if i bought that 670cfm doesnt it already come with the injectors?
I wouldn't even go to the Holley, too much headache for not enough gain. I would however upgrade the fuel pump to a TPI pump. You can also plumb an external EFI bypass style regulator to the return of the TBI. Most are adjustable from 20-80 PSI. With raised pressure your stock 55# 305 injectors can support pretty decent power.
hey fast if i buy the l31 hd crate motor like it is and dont replace the cam, how much HP difference are we talking about if i dont put the LT4 cam in it?
hey fast 355 ive been trying to get some info from you, if anyone else can help me it would be much appreciated.
im doing the 305 to 350 swap, and keeping TBI, ive decided to go with the GM 350/330 HO for warranty reasons and so i dont have to change much in it.
my question is about the throttle body i have know, if i purchase the 30 psi regulator that you talked about and plumbed it to mine, would i still need to get new 350 injectors, and if so what ones, do you have a link or a name. any info would be greatly appreciated.
thanks
If you raise the fuel pressure the stock 55# 305 injectors will work fine. The later model 454s used the 46# 4.3 injectors at 30 psi. I have also played with 36# 2.8/3.1 TBI injectors at 50+ PSI to feed 300+ HP.
I essentially have this combo in my car. The performer flat tappet that I have is very close to the LT4 cam, except it has slightly less lift, a touch more duration @ .05 and .006 and a tighter LSA. While it wont run 11's or anything like that, its definatly a fun setup for the street, works very well with the factory 2.73 gearing and stock stall, and still gets good fuel economy.
STOCK STALL?? IS THAT RIGHT... WHAT RPM IS A STOCK STALL, DID NOT KNOW IT HAD ONE OEM IN A 89 RS??? OR DID THEY
I am seriously considering on getting this L31-R for my 88 iroc and keep the TBI. 1 it would have potential for future upgrades 2 its new at a reasonable price 3 I am pretty sure with the right cam and exhaust and intake I could have 300 hp at the rear wheels and have decent MPG and a decent street car.
I am also considering getting a used one depending on my budget for the next few months. I decided that 300hp was good enough for me for now.
I am interested in this budget tbi build and am very interested to try this.
A fuel injection system is designed and calibrated specifically for the type(s) of fuel it will handle: gasoline (petrol), Autogas (LPG, also known as propane), ethanol, methanol, methane (natural gas), hydrogen or diesel. The majority of fuel injection systems are for gasoline or diesel applications. With the advent of electronic fuel injection (EFI), the diesel and gasoline hardware has become similar. EFI's programmable firmware has permitted common hardware to be used with multiple different fuels. For gasoline engines, carburetors were the predominant method to meter fuel before the widespread use of fuel injection. However, a wide variety of injection systems have existed since the earliest usage of the internal combustion engine.
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Sam Link Building
What machine work would need to be done to get the heads to accept a cam with lift of something like the LT4 hot cam? Also, would it be possible to run a set of 1.6 rockers on these heads?
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Thanks! I assumed it was something to do with the vavle seats, but you know what they say about assuming.
I've noticed that the pressure regulator (17113079) is no longer available at GMPartsDirect. Scoggin-Dickey has it, but it's $93.80...
If I were to modify the stock FPR, would it be capable of metering the desired pressure ~32psi?
Last edited by 91_5.7_TPI; 10-25-2008 at 11:07 AM.
for a true emissions legal setup, you will need the GMPP TBI Vortec intake and plumb the external EGR suppy to the intake from the driver-side header. (GM P# 12496821, $314.41 gmpartsdirect.com) If you painted the whole engine flat block with this intake, the smog inspector would really never even notice it wasn’t factory equipped this way. This intake also has all of the tapped holes, etc in the correct locations. You can even get a throttle bracket from several sources so that you can keep your stock cruise control setup, TV cable, and throttle cable.
I have two questions:
1. Could you post some more pictures of the EGR setup on this manifold? I don't understand why you need to plumb an external EGR supply. To me it looks like you just have a regular EGR valve. Or is that just "for show"?
2. Can the stock TV/cruise bracket be used? If not, which places sell one for this manifold.
Vortec heads do not have an egr passage to get the exhaust gases back into the intake manifold. So you need to externally plumb from the exhaust manifold to the intake manifold chamber. Then when the egr valve opens the exhaust gas can flow into the engine.
The mounting and bolt holes for the tv bracket do not line up with the bolts for a vortec intake manifold. In my case, a little bending and fab made it work fine or you can purchase one specific for a vortec intake manifold.
Damn reece146, it's his 1st post!!
But for real, 91custom, you really should at least read all the general rules, stickies, and all the announcements before you post. http://www.thirdgen.org/techboard/tb...uidelines.html
Learn to use the search feature, it'll be your best friend.
First post newbie to third gen. I was searching and found thid topic. I might be able to help others and gain some too. I am doing a dual TBI setup on a HO 383 going into a 1994 AWD GMC Safari.
Please take the to take a look at my photo's. I have not started my motor yet but I can help with the process up to this point.
Like I am the one to be talking but man that engine is almost too pretty to put into a van/mini-van. I can tell its a van/mini van origin TBI because your rear TBI is a front pull.
Like I am the one to be talking but man that engine is almost too pretty to put into a van/mini-van. I can tell its a van/mini van origin TBI because your rear TBI is a front pull.
Thanks, I think...
Yep, it came out of a 93 full size van. I had a 4.3 CPI in the van originally. The 4.3 is now sitting in the my barn.
I have a van complex... The Astro/Safari van is more like a truck then any "Mini" van. Go to my link above and look at the chop work this far. I'm keeping the AWD system (as this is the same as used in the Chevy Cyclone turbo).
Tell me what your running and maybe we will get together and see just what my "mini" van can do. If you think about it, it is almost a setup that you will loose any way it turns out. Sort of like fighting some old guy. If you win, you are looked down upon for kicking a old guys butt. If you loose, you got beat up by a old guy. Same here. If I win, you lost to a 'mini" van. If you win, it's no big deal as it's just a van.
I know you are just poking fun but us van/truck guys are sensitive. We have sports car envy.
The estimators have this engine around 500 hp and when you take off 100 hp to drive the front end it still should be a head jerker.
Yep, it came out of a 93 full size van. I had a 4.3 CPI in the van originally. The 4.3 is now sitting in the my barn.
I have a van complex... The Astro/Safari van is more like a truck then any "Mini" van. Go to my link above and look at the chop work this far. I'm keeping the AWD system (as this is the same as used in the Chevy Cyclone turbo).
Tell me what your running and maybe we will get together and see just what my "mini" van can do. If you think about it, it is almost a setup that you will loose any way it turns out. Sort of like fighting some old guy. If you win, you are looked down upon for kicking a old guys butt. If you loose, you got beat up by a old guy. Same here. If I win, you lost to a 'mini" van. If you win, it's no big deal as it's just a van.
I know you are just poking fun but us van/truck guys are sensitive. We have sports car envy.
The estimators have this engine around 500 hp and when you take off 100 hp to drive the front end it still should be a head jerker.
HAHA, I know how that one goes. Hell I got the original idea for this post from driving my then new to me Express with the stock L31. I have always felt it is a hell of a platform. With only a tune it runs great. I have beat many a L03 from 0-60 with it.
So you do have some van Blood in you! I will let you off the hook. I have since learned that you have some good times and the strip with your van. That true?
So you do have some van Blood in you! I will let you off the hook. I have since learned that you have some good times and the strip with your van. That true?
That is true. My 1983 G20 was running a 14.3 @ 96 mph in the 1/4 before the transmission (stockish with shift kit 700r4) let go. Building a stronger transmission as we speak. Th
was over at a custom engine shop getting some prices on various items for my l31 build.
I asked about intakes and he mentioned that the carb intakes dont work as well as the GM TBI intake but that intake is around 750 bucks CDN
Any other choices out there? Besides the rpm or air gap
Also I am looking to buy some tooling online to do the mods to the vortec heads I have IE spring seat mods and to cut the valve guide down and to get the guide cut for the new seals.
I am gonna go with the LT4 hot cam and thinking of putting in some 1.6 rockers.
Justin (IROC-Z Racing) 
I can tell its a van/mini van origin TBI because your rear TBI is a front pull. 
