TBI ideas thread

[Tylerz281500]

My ideas keep escalating as far as what a new motor will entail. Lets face it i cant leave anything well enough alone. my motor is tired, specd out for summit k1103 cam, edelbrock tbi intake and heavily ported heads that i did not stud and very well should have (nuff said). ive researched very heavily and will not carb swap or ls swap yet despite the peer pressure, i like my tbi, my cheap budget and tuned motor makes decent power for what it is.

so far in my research ive decided im using my 880 block, rebult per stock spec, nothing more nothing less atm besides glyptal and oiling holes drilled. m99hvs pump with spacer removed. probably reuse my 7qt pan on my current motor. double roller of course but it leads me to cam and intake and heads which i somewhat picked backwards. I hate my edelbrock intake, its going in the trash, I wanted to use my single plane wieand, and after some research it looks as though TBI seems to be quite comfortable with it from what ive read and searched. heads im acquiring some sportsman 2's already studded and 1.6's, i could throq a polish job at them but may leave them, camwise i wanted to go a bit crazier and saw a few threads based on the voodoo 60101(different part number now) and had great results. and that was my build plan...........

Up until a few days ago when i considered a blowthrough setup with a ford intercooled m112. seems as though 19/hr 454 stuff at 13 psi will be fine. im reading up on tbi and blowthrough as we speak still, found a decent way to mount it and run serp so i guess tuning is my largest obstacle. I havent found a ton on the supercharging aspect though, anyone have any recomendations? ill need to find a new laptop as mine died but im already set up with the moates G1 and everything needed for chips, my last tuning experience i relyd heavily on eaglemark who is dearly missed so im on my own this time.

anyone have any thoughts/concerns/suggestions? did i miss anything or overlook anything? should i change anything before i go ahead and buy things so i dont have to return them?

[1project2many]

The GM TBI regulator is referenced to atmospheric pressure. When adding forced induction the regulator should be referenced to manifold pressure to reduce the dynamic range needed by the injector. But the low pressure 90#/hr TBI injectors may not play along as fuel pressure increases with boost. If the injectors will work you'll want to make sure your pump is capable of the higher pressure. Stock replacement TBI pumps are not. Since you're running supercharged you could use PE mode for the job of adding fuel and removing spark as RPM increases. You might end up disabling MAP codes as the MAP voltage will be at peak value whenever the engine is in boost. There are few safeguards available so lotsa datalogs and care while tuning would be wise. You might want to keep static compression on the low side to allow a little more room for error.

I don't believe I'd spend money on high lift, high flow heads for a small cam TBI engine. I'd recommend doing research into how low lift flow affects a street engine. It's probably a good idea to think about how a wet flow system can be affected by such factors as poor port velocity, large plenum/port size, and intake manifold heating. You're planning a forced engine so maybe a stock-ish head with good low lift numbers like the L31 would be a good choice?

Don't throw out the Edelbrock intake. Sell it for parts $$.

[Tylerz281500]

alreadyrunning a tpi pum so my fueling should be acceptable. ive never messed with forced inducton but as i suspected and hoped im missing some stuff oviously. tuning will be my hardest part, the SC was an idea after i specd everything out such as the cam for NA. i just thought they may cooperate. heads i already have so ill use them, i think they are still a good choice for what i want to do wether NA or Forced. low lift? really? so stick somewhere around the cam im already at then? any threads on low lift velocity and such? i thought about vortecs, but dismissed it after researching briefly on the hi rise intakes on TBI acting well, and since i already have one with carb intake pattern i thought the sportsmans would be a good option to mate them, flow decently and are already set up with studs, 1.6, good springs etc

allright maybe ill sell the intake, i cant stand that stupid thing though, was a waste of money.

[Tylerz281500]

Been reading up on cmas and such for supers and what not. alot of people runnign 110 duration and such, and as much as the stock cam stuff is admitted alot of dyno results are showing 50hp improvements NA with cam in most cases, and 100hp average gains with Vortechs, whipples etc, now these are on aftermarket injection motors or carbd but boost always drops when compared to a more stock series cam as they are allowing it to breathe better, im thinking ill stick with my choice, not trying to be stubborn but i think it will benefit me more than expected. i also want to stay close to what the tbi is gonna like tuning wise and that may also make the voodoo cam worth it. power level may suffer a hair down low but im ok with that.

so far
fuel: tpi pump 454 pod and injectors with AFPR
2bar map: new from dealer at cost, not sure what i have to do tuning wise to get that to work, just adding things to this so i dont forget. ebl flash would be nice but pricy

[1project2many]

The cam you want to run should be ok. It isn't a big cam but the heads are made for bigger cams. Mixing ported heads with larger ports and valves plus small cam can work against you. If you're set on the head then try them. But if you're having a bunch of trouble making around town, off idle, light crusing work ok then maybe consider swapping out. If you switch to 2 BAR sensor then a lot of other stuff gets messed up... everything with a vacuum or MAP setting has to be changed to work right.

What computer are you using?

[V8Astro]

I ran a Weiand 142 on a small block for a few years using TBI injection. I had one of the original EBL's. Stock BBC 90# injectors worked fine for me at 30psi

I wouldn't pair a SC with a cam that has 110* lobe separation. You'll be pissing into the wind. Tight lobe separation capitalizes on intake reversion which becomes mostly irrelevant when you have an "air shovel" cramming boost into the cylinder

[Tylerz281500]

goo dinfo guys, the heads are plausibly sold from under me, so thats totally up in the air. i can either try them if i get them or ill eb runnign a different sbc based head with some work.

im told 2 bar is the way to go? is there a way around it with boost? i havent looked into any of the tuning aspect yet but from what ive seen on one fellows build he has the whole required steps to build boost with a tbi setup and it seems like good measure to run a 2 bar.

intake i cant remember part number but know its discontinued. cam is 112lsa from what i saw http://www.summitracing.com/parts/lun-10120702lk/overview/

from what i recall bcc was BDJY ill have to pull computer back out to find the numbers, i had all my info in a file and i cant seem to find my file now. i have pictures of it somewhere too that im not seeing. its a 93 gmc, 5.7/60e

v8astro oyu have a build thread on that or something i can pick through info? bear with me guys ive never run anything but NA big learning curve here

[1project2many]

The ecm doesn't know what sensor you have attached. It knows what voltage is supposed to equal a pressure. At any give pressure the 2 BAR gives voltages that the ecm thinks are for a different pressure. So the ecm will never know what the real pressure is. So you will have to change everything related to pressure. It can work. You just have to make the changes.

[Tylerz281500]

ahhaaaaaa that makes sense i thought it was actually plug and play but im assuming youll have to swap files in the computer or something for it to read. or probably end up using alot of segments from the scy/ty programs in the 5.7 ecm

[1project2many]

Segments are an OBDII thing. Code wasn't so modularized in OBDI... no sections that can be swapped easily. You would have to change all the MAP values to lower numbers so they would match the 2BAR reading. IOW you'd have to lie to the ecm wherever there's a MAP reading. And in turn, it will lie to you whenever it has MAP or Vacuum information to provide.

[Tylerz281500]

i still want to proceed with a remote mount m90 or m112 but i think with the specs of the build i want i can run it NA just fine and thatll get me back into the whole tuning thing again because ive been out of it for awhile and dont remember a ton. how would i have to lie to it? wouldnt the computer then to told to read properly via a 2bar?

[1project2many]

Computer will not read 2 BAR properly. It will think 14.7 psi boost is 0 psi. It will think 0 psi, atmospheric pressure, is vacuum. It will think vacuum is more vacuum. ECM will only use about 1/2 of main spark table NA. ECM will only use about 1/2 of VE table NA. Other values will have to be adjusted to match what ECM will actually see.

I'd consider using MAF code and skipping pressure measurement.

[Tylerz281500]

not using 2 bar at all? s there a writeup on the basics of adding maf to tbi? best maf to use etc? something i can read up on? and thatll completely eliminate my map? or i keep the stock one still

[Tylerz281500]

ok got a bunch of stuff figured out,

things im not finding info on.

-what had a 3 wire o2 from factory?
-mechanically how does a VAFPR work? and can i make my own? im not finding any info on what spring diapgragm to use or what else is needed to make it vaccuum.

[V8Astro]

I use a 3-wire O2 in everything I tune. ACD part # AFS-74. Recommended by RBob for use with his EBL and the 7747. I installed one in my truck recently. Using a relay for key-on power to the heater circuit.

I used an Aeromotive regulator with my supercharged setup # 13301. I cut the center out of the stock TBI diaphragm so the fuel would pass thru freely. The regulator was down-stream of the TB. I originally tried a setup where the fuel fed to the TB with one line but it would vapor lock. The flow-thru system would purge ok. I had it for a couple years until I went turbo and things got really out of hand haha

[1project2many]

This should give you some ideas.

http://www.ebay.com/itm/VAFPR-Vacuum-Referenced-GM-TBI-Regulator-Kit/231579463461?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%2 6asc%3D34008%26meid%3D1de1c0bd55c14611974cbd29745b 2c61%26pid%3D100011%26rk%3D1%26rkt%3D1%26mehot%3Dl o%26sd%3D261626762309

[Tylerz281500]

got any pics. im not looking at it right now but wouldnt that regulator cause trouble with my current regulator thats inline the pressure side due to my tpi pump?

how are you cutting out the center and blockig it?

ill be NA before charged so its good info on both