Hi another newbie here. I have a 91rs with the lo3, auto. Ive upgraded it when I bought it in 98. Some of the mods are.

Holley projection intake
edlebrock headers with 3in y pipe
3in exhaust
extreme efi 700cfm tbi
160 degree thermostat
accel high voltage coil
MSD cap and rotor
Ultra 40 wires
e3 diamond fire plugs
silencer ring delete
custom made intake with ss ram air hood functional
K&N filter
Jet stage 2 chip(Now for sale)
Ebl flash
March under drive pulleys
EGR delete

Those are the engine mods that Ive done My questions are,

1. To set the timing would it be beter to reinstall the stock chip while seting it or does disconnecting the brown/black wire bypass it or does it matter.

2. Is the stage 2 chip actually hindering me in performance area as Ive read in some areas.

3. Is the 160degree thermostat also hindering me?

4. Ive read alot on burning own chips ect is there a way I can buy a custom made chip that will work for me or will it have problems? I just didnt want to get into all the work of it. Buying the equipment and Learning how ect,ect,ect.

5. I know the TBi is a little big but I started this build with bigger intentions and also by myself before I learned about this site. Question is what should I do next for performance help?

Iknow alot of this stuff was probably address at some point. With lots of reading in the last two day I have not really got the answers. Plus there is a lot of bickering about this and that I just didnt really want to read anymore so here it goes and thanks for all the help and suggestions ahead of time!!!!!!!!!!

 

For #1, with the EST/BYPASS open the ECM can not control the timing. So it doesn't matter which chip is installed.

#3, I've always preferred 180 or even a 195 thermostat.

RBob.

 

T#3, I've always preferred 180 or even a 195 thermostat.

Thanks for the reply to some of the questions. So the 160 wont make more power, or is that because of over heating issues on hot days with ac running. Or is it the chip is tuned to that specific range. I believe the stock was 190 so to leave it that way was better?

So the link on your reply should that be my next step? I have a laptop already so for $380 plus shipping is how I could make my own ecu tunes ect. Should I switch to WB o2 also? How hard is it to do with no experience in tunning any of that stuff for a first timer?

 

No work if you get EBL flash, you just plug it in and load your bin. Must have equipment is the lap top, the NB 02 is ok for a decent tune, you can always due a few sniffer test for confirmation.
I had better experiences with the 180 Tstat and a 200/210 degree fan switch.

 

My fan runs all the time with key on has since I bought it in 98. Is it not supposed to?

 

Not supposed to. Someone wired it that way, The fan switch probably went out and that was their quick fix. You can always pick up an adjustable and wire that in. More control when you want it to turn on.

 

EBL can also control the fan.

 

I dont think its wired wrong no splices that I know of and the sensor on the side of the head was replaced when I put headers on years ago (I broke it and had to replace) and that didnt stop it. So it must be the relay right? If someone were to wire to come on with the ignition switch what would be the easiest way to do that and have it look like it came that way so I know what to look for.

Plus Ive read lots of the coolant articles and Nobody really came up with a decision on the better thermostat. One thing I know they were wrong about was that the cooler engine lasts longer. It does not. The reason for the higher temp by the manufacturer is for upper cyclinder lubrication. Back in 98 it was the first thing I had switched out even knowing this about upper lubrication because of the extra power I was told the cooler engine would make. The Nascar guys run even hotter than our street car temps to keep the wear in check so the engine lasts longer at high rpms for extended periods.

 

The small ground wire on the fan relay (often green with white stripe) would be grounded in order to trigger the relay on with the ignition.
That's all the fan switch does, - ground the relay at the proper time.

Sometimes the two main 12v+ contacts inside the relay will fuse together locking it in the ON position.

Question one - already answered.

I like 160 - 180 tstats depending on how efficient the cooling system is and what type of driving I'm doing +season. It is best to make adjustments to the ECM calibration for a lower temp tstat, especially the 160*, though it will work fine most of the time without.

I like a hot oil temp, but cool coolant temp. The lower coolant temp is great for controlling detonation. For a performance engine tuned near the edge, detonation will cause more damage than slightly accelerated cylinder bore wear. A cooler coolant temp will often pick up power on a high mileage engine due to the pistons expanding relatively more than the cylinder bore - making a slightly better fit with less piston rock.

IMO, the EBL-flash system suggested above would likely be your best option to control & tune what you've got. Follow the EFI link in RBob's post.
I highly discourage using an aftermarket performance chip, as they usually cause more problems than they solve.

As far as mail-order tunes for your combo, some are better than others depending on who you are working with, but should be a second choice to having it tuned in-person or by you.

Your TBI should be fine. I think your next mod should be to get a handle on the tuning/ECM control first. practice with that for a while, then look into cylinder heads and camshaft.

 

Thanks 305sbc, I will look into the fan later. So do you think it would be better for now to run my stock chip instead of the jet stage 2 chip? What cam and head combos are recomended for my setup? Anyone?

 

Okay so after reading alot. I realize until Ive got the tunning down then not to even look into heads and cam. Could I throw a set of 1.6 rockers on it thou or would that be the same or similar to the cam. I heard somewhere the computer would learn as long as it always had power and compensate for the differance.

 

For the fan running, there are three items that will turn it on. Note that this is from the '92 FSM, so may be a little different then a '91 car. All three control the fan relay and will enable it.

First is the head coolant temperature switch
Second is the temperature control head in the dash. Any time that A/C MAX, NORMAL, or BILEVEL is selected
Third is the A/C pressure switch. High A/C pressure will enable fan relay

Each will provide ground to the relay coil to enable it.


You asked about 1.6 rockers and the tune. No issues there. Not enough of a change to affect it. However, I don't think that you should go with them now if you are planing on changing the heads in the near future.

Roller rockers are not cheap, and you will need to comprise your selection to fit the stock heads. Better to wait for the new heads and then get rockers to go with them. An example is the Comp Cams Pro Magnum rockers. They require a longer stud since the trunnion is thick.

So they can't really be used on stock heads. And stock heads have pressed in studs. Unless they get machined for threaded studs, it is a no go.

At the same time, since a longer stud is required, then get them in 7/16" along with the rockers to fit. This is better as the larger stud will reduce flex in the valve train. So you kill two birds with one stone.

RBob.

 

Well thanks for that I thought there was a stamped steal roller rocker that was a direct replacement that could work and be had on summit for fairly cheap. Netting around 10 to 15hp. I guess Im wrong, wouldnt be the first time! Thanks!

 

Okay have been away awhile. The fan did have a splice on the green with white stripe wire that was grounded. It just looked factory the way it was done and didnt notice it. Removed and seems to work like it should.

Ive been out working on it and noticed it is running rich and pops when I rev. it. I noticed the injector pod. was not only spaying but every once in awhile a drip would come off of the pod. So I ordered new ones I have ordered flow matched 55lb injectors from a 350 engine.

I think with the larger than stock injectors I will definitly need to tune it.
Rbob if you can give me a list of things I will need and prices please. To do so.

I know the running rich problem was not a problem Ive always had. If it is still there after the injector change is there something else to look at. I had this problem before installing a new cap, rotors, wires, and plugs and after the upgraded stuff it seemed to get worse. Why?

 

You already had 55lb injectors from the factory.
Also dosent sound like you are running rich.

 

You already had 55lb injectors from the factory.
Also dosent sound like you are running rich.

WHAT??? Every where I looked showed the lo3 had 40lb or 44lb. The ebay sight I bought from said that 55lb from a 5.7. Plus other sights said 55lbs were from 5.7. Is there more clarification on this? So it doesnt sound like Im running rich? Im not geting back fire in the intake sounds more out exhaust. I also smell gas. I can run it in the mode so the light blinks on the dash to see if which way it is running will do so later. I will take Ideas and suggestions for now.

 

After further investigation I found on here some of the threads listed them as 61lb injectors. I wonder why they were listed as 55lb injectors. Part#5235206.

Ive desided to buy the ebl flash. What kind of power would I see with the setup I have and good tunning. Im I right to say that the 61lbs would be a better?

 

I had to go trough the etire post quickly, appears you have 3 upgrades, once tuned: full exhaust +15hp, free flowing air filter sitem maybe +3hp and 1.6 rocker +7hp. You should get another 10hp out of a decent EBL tune.

Higher fuel pressure with smaller injectors is the way to go.
The 61lbs injector will support 221hp with stock fuel pressure. The good thing is your 61lbs injectors with 25psi fuel pressure are good for 320hp (vs 288hp for the 55lbs injectors @25psi) probably won't need to buy injectors for a while

Do not belive and use the ebay scam statements as reference.

 

So the Holley projection intake was a waste of money or was that missed,and the 700cfm tb. I dont have 1.6 rockers yet I was told that I couldnt put them on my stock heads. I thought summit sold a 1.6 roller rocker that was a stamped steal kind that replaced the stock ones?

Okay so I should just stick with the stock injectors and crank-up the pressure instead. Or should i just through in the new ones because I have them?

 

The stock intake manifold and TB aro no restriction up to 280fwhp. Its already incredible luck if it runs good with the 700cfm tb. What are the bore sizes of the manifold and TB?

First datalog to make sure you need to increase fuel pressure, if out of fuel icrease FP and adjust in the calibration.

Since smaller injectors with higher fuel pressure are more effective, I would keep the stockers untill out of injector/fuel.

 

[quote=thomas1976;4463098]The stock intake manifold and TB aro no restriction up to 280fwhp. Its already incredible luck if it runs good with the 700cfm tb. What are the bore sizes of the manifold and TB?

The bore sizes are 50mm for both and the tb has basically the ultimate mods done to it also. I believe the intake is a restriction at that same point (280hp). It is considered a highrise dual plane tbi intake. So It sounds like I wasted money on it. I could have bored the stocker out to get the same result. The olny reason I had bought the 50mm was that I wanted to build a nice 350 or 383 at one time. I had two spare engines and started building. Well I got laid off and sold my spare engines ect.ect. ect. Things are still not that great now but I have a little money and want to make the best of what I currently have.

With my fuel presure all the way down it sits at 13.5 so if I have 55lb injectors this probably would put me right in the ball park of what I needed in terms of the power Im currently making. I guess I should have just ordered new flow matched 55lb injectors. (Well thats what I thought I was ordering.) I figured 58lb to 61lb range. So understanding my injectors are 61lbs at 13.5 they would probably flow way to much right now.

 

In theory the 55lbs@13.5 are good for 212hp and the 61lbs@13.5 for 235hp.
As the FP, changing injector size changes fuel delivery # and needs to be set up in the bin./tune.

 

My understanding of the ProJection intake is that it is a decent step up from a stock intake. The 700 CFM TBI may be a little overkill, but at the same time once you start to open up the breathing (headers, exhaust, cam, intake), the stock TBI unit will then be a restriction. And the 700 CFM TBI then isn't so much overkill.

And of course can take that engine or a larger to the next level.

It can be difficult to buy parts for a current engine with a future engine in mind. It becomes too much of a compromise.

From your original list, check the exhaust board on headers. For some reason I don't recall the Edelbrocks being high on the list. It was the Hookers that ended up being better. But please double check me on that.

Accel coil, better off with the stock GM coil. Same with ignition modules, stock GM. The MSD cap & rotor should be OK.

RBob.

 

Everything in that list was what I already had. I guess I need to start selling things, and planning out again. Sell used to buy used. I wish I had known this site earlier like back in 98, but Im sure even then many people didnt know what was best. If the present day people are still trying to fiqure it out or coming around with whats best.

 

I need to learn to read better. I was thinking that this was what was being planned, not what is already on the car. With the Edelbrock headers already on the car I don't think I'd pull them off. Too much work for any gain.

Although the Accel coil I would change out to an OEM one. They don't seem to hold up and is liable to leave on on the side of the road some day. Same with aftermarket ignition modules.

You have mentioned stamped roller rockers. These would be roller tip only. Would be better off going with a cam change. The LT1 take outs are a good choice. Although they did put LT1s in a bunch of different vehicles. With that an f-body pull out would be the better choice.

The stock L03 cam is so small even 1.6 rockers won't but much.

RBob.

 

Thats okay Rbob this thread is going all over, Thanks for all the good info.

Your money will be going out tomorrow so expect it probably befor friday.

I have something from the people I was buying injectors from and asked if I could return them for the regular 305 55lb injectors and this is what he sent me in reply.

So much miss information out there. All GM 5.7L motors came from the factory with 55pph rated injectors -except for the 5.7L police car with the 9C1 package which were rated at 65pph. The 65pph injector is very rare and has a completely different part #. If you can find the 65pph injector - they usually sell for $200 a pair. Back to the 5.7L 55pph injector. They are factory rated at 55pph which means they can vary from the low 50s to the high 50s - which is why we flow match them. How do we know this - 1) we flow test every injector and the flow bench doesn't lie - but, if you don't want to believe that then 2) Every PROM requires that you program in the injector size and guess what, the GM PROMs from the factory are rated at 40pph for a 305 motor, 45pph for a 4.3L V6, and 55pph for a 5.7L motor. No 5.0L GM motor ever came with anything but 40pph injectors. You are getting exactly what was advertised. Please don't believe other online forums that are famous for publishing wrong info. Thanks


- save$sales

 

Yes, lost of different information around on this subject. If you dont trust the flow# of the seller, you could try to get in touch with dctrumpet, he is a tg member offering some flow matched injectors, im sure he can help you out.
It has been reported that the injectors dont flow all the same from the factory, thats also why you have them flow matched, it may be possible that some 61lbs flow closer to 55, and some 55lbs closer to 61.

 

Well yesterday I threw those flow matched injectors in. Once I got it to start, it ran good smoother no popping and seemed to have much better throttle responce. I have not drivin it so Im not exactly sure. After awhile of running it went back to running very similar to the way it was before popping when I wack the throttle. Put the flashing check engine mode on the dash and It seems rich most of the time except at idle, very seldom it registers lean. When I shut it off it will not start back up unless I give a touch of throttle. Kind of like starting an old carberated engine. When I get my EBL Flash should I beable to get it to run right or will I have to take the injectors out and replace with the 305's injectors? I think that there is more going on because it ran that way before the injectors, but it did start with out giving it throttle befor. I was wondering if someone had an Idea on whats going on. It didnt always run this way with the setup I have it did run good at one time. Well Im sure when I get the EBL flash that I will probably figure it out as I will beable to hopefully see it on the HUD. My idea is that it maybe the Map sensor because the O2 is fairly new. So is the cap,rotor,wires,plugs,TPS,IAC. I also checked the TPS for correct operation and reset the IAC after installing the injectors.

 

For the popping on a WOT wack, most likely the fuel pressure is dropping off. Either a clogged fuel filter, split hose in the tank, or the fuel pump is on it's last legs. Do not use a 255 lph pump if you replace it. Better off with a TPI pump or at most a 190 lph pump.

The other item that causes a intake back fire is a lack of spark timing. However, if it is set correctly then don't crutch the lack of fuel by adding timing. That will just cause other issues.

With the EBL it is easy to adjust for the larger injectors. The BPC vs VAC table takes care of 95% of the fueling changes. Then reduce the two AE PW tables by the ratio of the change in injector size.

RBob.

 

The pop sounds more out exhaust. It will usually pop before I get to WOT. I made sure the timing was set correctly how ever I did notice I ran much better with that timing connector unplugged and reved it with it unplugged and no popping issue. I have a pressure gauge hooked up in line and it seems to stay right a 13.5 even when I wack it. Im thinking of putting the stock chip back in to see if that helps. The only thing with that is that I know it used to run pretty descent before so I dont really think its a chip issue.

 

Well the not starting unless giving a little throttle was because the diagnostic code reader was still plugged in.Doh!!

 

Okay I just installed the EBL flash board in my ECM. I have not put it back in the car yet. Im sure this is the next step. What do I do after that? I expect it is load a BIN how exactly is this done? Is there a thread on this? Iv already down loaded tuner pro. Someone please lead me in the right directions.

 

Load the stock LO3 bin not sure anymore but probably something like F ...bin..0016, from the cd.
https://www.thirdgen.org/forums/diy-...o3-lt1cam.html
https://www.thirdgen.org/forums/diy-...g-what-do.html
This is an exemple of a smooth SA table, you can try it, should work ok.
https://www.thirdgen.org/forums/atta...hed.lo3.sa.jpg
This should get you started.
Tuning related posts are mostly in the "DIY PROM" and "DFI & ECM" forum, with the search button you should find a tremendously long EBL tread.

 

Connect the laptop to the EBL, turn ignition on (not run), klick on "display", select "flash", then select a bank, "action" schould be on "update bank", klick "select bin", select the bin from the cd and klick "apply". Done.

 

Thanks Thomas for being helpful on more than one occation. I will go and try later tonight or sometime tomorrow.