Hi everyone, I've been talking the guys at turbo city to figure out some ideas for the engine I'm building, but I'd like to get some input from people who have experience with TBI performance and AREN'T trying to sell me stuff lol... I've read the stickies as well as lots of other stuff, but I'd like to hear from you guys what you think of my combo, as well as what you think of my future plans...

Here's what I have right now:
1:)Stock LO5 short block out of an 88 Chevy Suburban (slightly off balance at close to 4,000 rpms thanks to .040 over flat top pistons, .010 under crank journals, and no rebalance lol, oops lol).
2:)Stock LO5 swirl port TBI heads, rebuilt and milled slightly, with Crane Valve Springs.
3:)Crane Compucam (Powermax) 2030 Cam (204 and 214 duration, .423 and .446 lift (with 1.5 rockers), and 110 degrees lobe seperation.
4:)Crane Anti Pump Up Lifters (not the cheapos that cam with the cam), and one piece forged chromemoly pushrods.
5:)Crane Gold Race Full Roller Rocker Arms (1.5, non self aligning, narrow body).
6:)Edelbrock Performer TBI intake manifold.
7:)MSD Pro Billet Distributor and Blaster Coil (TBI direct replacement style).
8:)Stock TBI Unit and Injectors (55lb hr), with the stock regulator spring shimmed to 14.5 psi fuel pressure.
9:)Hypertech Thermomaster Chip and 160 degree thermostat.
10:)Stock truck style air cleaner with the thermac removed and sealed off.
11:)A.I.R. system removed.
12:)Edelbrock T.E.S. headers and Y pipe, no cat, flowmaster muffler.
13:)Retrofitted a late model 3 Wire O2 sensor in place of the OEM 1 Wire O2 sensor.

And here's what I want to do still...

1:)Pull the engine back out and rebore it to .060, and install a new balanced rotating assembly (so I can run it up to 5200 rpm or so).
2:)Replace the cylinder heads with ones that don't suck lol.
3:)Get a bored out TBI (Turbo City 625 cfm with injector spacer).
4:)Get a new Fuel Pressure Regulator (Turbo City Adjustable or Vacuum Reference?)
5:)New Match Flow Injectors (65 Cop Car or 75 Big Block?)
6:)Custom Prom Chip.
7:)Higher Flow/Pressure Fuel Pump.
8:)Hypertech Powercharger and K&N E1500 Air Filter and MSD 8.5 Plug Wires (should have done these already lol).

I really need to know what you guys think of my current mods and future plan mods. Also here's what I can't decide on, firstly it's the regulator and injectors.

1:)
Turbo City claims that I should use a Static FPR (constant pressure) and the 65lb hr injectors, as the big block ones will give me a poor idle, and the 65lb ones will get me the HP I'm looking for (300 to 330 hopefully). With only 2 injectors though, a max duty cycle of 80 to 85%, and an approximate BSFC of .50, I don't see how the 65's at stock pressures (9 to 13) could possibly fuel 300+ HP. I can see the 75lb hr ones overfueling a stock motor at idle, but I wanted to use a Vacuum Reference FPR to lower the high vacuum fuel pressure and prevent async at idle, and this will not be at all a stock motor. The VRFPR would have 17 PSI at WOT, making the 75lb hr injectors flow 90lb hr, but the pressure would be down to 9.5 to 10.5 psi at idle giving it a good clean idle mixture. All of this would be run with a custom chip of course. Turbo city did say I could run the TBI either way (65's with an AFPR or 75's with a VRFPR), but that it would be harder to program a chip for the latter due to the varying fuel pressure. However, beings that the computer knows the engine vacuum, and it's easy enough to figure out what the fuel pressure is at different vacuums, I think it shouldn't be that hard.


2:)What kind of fuel pump should I upgrade to? I wanna use a stock type in-tank fuel pump, and I want one that's reliable (AC Delco possibly), and one that's not gonna over power the regulator. I heard you can just swap in a TPI fuel pump, but I'm not sure.


3:)Lastly, I wanna know what kind of heads I should use. I been thinking I could possibly get the stock 193 heads pocket ported and combustion chambers unshrouded and high flow stainless (possibly larger 2.02 and 1.60) valves installed, but I'm not sure how much it would cost or how much it would help. Option two would be some World S/R Torquer heads, but I read in their instructions that you have to like, drill em to activate the EGR, and all the bolt holes need to be thread sealed (ALL of them), and you have to disassemble them and have the valve cover ridge milled to use center bolt valve covers. Option three would be Edelbrock Performer Centerbolt heads, but those are kinda way expensive. Any suggestions?


Any input would be GREATLY appreciated. There's alot of info floating around on the web about this stuff, but I'd like to get ya'lls input, cause it seems like you guys know what you're talking about.

 

If the ring seal is in good shape (no smoke) there should be no reason to bore it out further.

I highly doubt the over-bore and undercut bearings are causing your vibration. It's more likely that the balancer has slipped or something else is amiss. The over bore would only account for grams of weight. The only engine I've ever seen that "needed" to be pulled back apart to be balanced had a set of lunati pro mod rods, forged pistons, and stock balanced crank. Even it only had a hint of vibration at around 3000 rpm. The vibration could even be caused by a misfiring cylinder. I think you are chasing your tail on this one.

For the TB, you may just try to get a 454 unit off of ebay. They have 2" bores and anywhere from 70-90 lb/hr injectors all for less than 150$, throw in a rebuid kit and a can of carb cleaner and you are good to go.

You need a regular fuel pressure regulator unless you run the EBL system. You are on the right track with changing the VE curves based on the engine vaccume, but in practice it doesn't work out very well with the stock code. With the EBL system Rbob has added a table that will allow you to compensate for the changing FP.

You can tune around just about anything if you DIY. There is no way a mail order chip will get this motor running well as you just have too much stuff changed from stock.

You do need a better fuel pump, the popular choice is the walbro 190 as any larger of a fuel pump will over power the stock return line and cause the fuel pressure regulator to not keep up with the flow. A TPI pump will work but a walbro cost the same so it makes sense to go with the bigger pump.

As for heads, I wouldn't waste my money in the stock heads. The SR (stock replacement) heads are ok but for the money you can pickup a set of vortec heads along with an intake and make about 30 hp more than the SR's. Keep in mind you will loose your EGR with the vortec heads. There is a GM intake that has provisions to mount an EGR valve but requires you to plump in the exhaust externaly.

 

Much appreciated, I was actually considering doing a vortec conversion and selling my current intake. I would also need to get new rocker arms and plumb the EGR from one of the headers. I guess Turbo City has a whole setup (chip and TBI unit) made just for the 330 Horsepower 350 crate motor from GM Performance parts (the chip is dyno tuned even, supposedly), and I could real easily duplicate that. I think the cam in that engine is a tiny bit bigger than the one I have, but I'm sure it would be easy enough to get a hold of that one, or just hope the one I got works (prolly does). Few questions about that though, how hard would it be to plumb the exhaust from the header to the EGR, and is there a kit or some part numbers that would make this realy easy and not super ghetto?

Also, do you know if I still need to run narrow rocker arms with die cast aluminum valve covers (proform)? Cause if I'm gonna get new ones, I kinda wanted chromemoly Comp Cams Pro Magnum ones (in favor of the Crane aluminum ones), but they don't come in narrow body. I noticed there are no internal reinforcements in the new valve covers like in the stamped steel ones, but I didn't know if the bolts themselves or the baffles would still get in the way. Guess you might have to have actually tryed that to know though, but I don't know.

Any input would be awesome though... thanks.

 

Even small differences in the motor will necesitate changes in the chip. You can build two identical motors and tune them seperatly and the tunes won't be the same. The TBI ecm's rely heavily on the VE tables unlike the a MAF setup, so mail order tunes just don't work like they do on the newer LS1 type ecm's. Close enough works on those types of ECM's.

The bolts will be the problem, so narrow rockers would be required. If you are willing to spend 300$ plus on rockers you need to take a step back and re-evaluate where you need to spend your money. A set of AFR heads will give you more bang for your buck than any other mod you can bolt onto your motor.

You can simply disable the EGR system in the chip and just run the EGR valve as a dummy to get through a smog check. I highly doubt any smog **** would have a clue how the EGR worked with vortec heads let alone be able to even spot vortec heads.

 

If I were building another engine today, I would switch to the later model TBI PCM and run Dimented's MAF code, like I have already done.

That being said, with a properly dialed in chip, big block injectors will NOT idle poorly. My old 305 had 125# of injector flow, per injector. 68# injectors @ 32 psi. The result was 423 FWHP @ 6,600 rpm out of 312 cubic inches. It had a nasty little idle to it too.

The first run was roughly 1/2 pedal through 1st and 2nd. The second was WOT short shifting first.

http://videos.streetfire.net/search/...050122bb79.htm

 

IMHO, I would consider a completely different ECU entirely. I know a few people who've had tremendous success with stand-alone setups on their TBI equipped vehicles, especially with a unit known as the MegaSquirt. My TBI project has been on the back burner as of late due to this twin turbo 3.1 build I got going on, but am definitely ordering two MegaSquirt systems for both projects, way ahead of time. Leave the ole chip swapping/burning method where it belongs, in the past....

 

one question...why go TBI??? why not just go carb?

 

^ Really no reason to. Took this throttle body that I was working on these last couple of months ever further than the last pics I had up, so it's really not a matter of air, fuel or spark (in reference to TBI). Rather, tunability. MegaSquirt has something known as "auto tune", which will tune your engine (regardless of what injection system it came with), on the fly, for you. Let's see a carb do that, unless you like carrying around a small screw driver....

 

It was 10*F outside the morning this was taken.

http://youtube.com/watch?v=FmS1m3zlqHo

 

amazing wealth of info all in one place. i just bought a 350 TBI from a caprice cop car and am planning a similar buildup so I'm sure I will be referring to this many times.

just wanted to voice my thanks.