Na306StAnG

Long time lurker, first time posting..

I have an 85' GT mustang with a carbureted LS1 in it. I've been tossing around the idea of selling it, and never really finished putting the car together. After trying to sell the car, and not finding anyone interested in buying a half finished project, I've decided to play with her.

So within the last week, I finished the wiring, and plumbing for the fogger system. The car has been to the track before, but with a very basic tune, and only N/A.

I'm kind of new to the whole LS1, but not to a carburetor. I've heard stories, and read threads online about the LS1 not benefiting from a lot of timing. Being a carb guy; my past builds have all had about 38+ degrees (N/A) of timing. So knowing the fact the LS1 don't like a lot of timing, I've been stalking the carb database sticky and notice most guys not going above 34 degrees.

So, last night, I take the car to the track and attempt to spray it.. I have a total timing set at 32 degrees for N/A. When the nitrous is activated, It pulls 10 degrees. Let's not go into the fact that a fuse pwnd the nitrous from working.. Will save that for another day. Basically, the nitrous didn't come on, and the car was soo lazy due to the 22 degrees of timing, it led me to tonight; where I decided to give the car 40 degrees of timing while driving down the street and inputting from 32 to 40 degrees it felt like we got rear ended by another car. It's mind-blowing how much different 8 degrees made just N/A.

What do you guys think would cause it to enjoy timing so much? It is a custom comp cam, and it was degree'd in.. But for it to like THIS much timing, and it be a custom nitrous cam, the last thing I'd expect is for it to enjoy the amount of timing I've given it. Right now, I'm just thinking out loud. My plan is to go to the Dyno and watch the numbers to see exactly if it's gaining anything. But by watching the Air-fuel, I'd say it's definitely gaining something, just the seat of the pants alone is worth it!


Teh car:

ZONES89RS

iTrader: (25)

At 34 to 36 it is probably happy as can be, at 40, there is probably no gain above 36 but no loss either, so I bet at 36 total it would feel the same as 40.

butler

difference between carbed timing and efi timing is tremendous. It takes more timing. Mine ran best 35 to 36 total.

Na306StAnG

Not completely true, the design of the combustion chamber is the main reason the lsx motors doesn't require as much timing as the older small blocks.

butler

I was not referring to the old small block. Ls1 carbed vs efi. Carbed takes more timing then efi. I speak from experience.

Na306StAnG

Gotcha, so generally a carb'd lsx requires more timing then an efi'd lsx setup?

I'm up to 43 degrees and still feel an increase in throttle response and acceleration but the wideband showed it getting lean. I'm gonna put it on the dyno in the next week to see what the dyno can tell me.

xpndbl3

iTrader: (23)

i never calibrated my butt dyno to show increases of 10hp/tq. Better watch those plugs with that much timing in there. I know mine was pretty much maxed out at 34 by looking at the timing mark on my plugs.

butler

I know a guy running a 454 lsx motor distributor l92 heads and runs 36 degrees advance. 9.2's on motor is his best 1/4 mile time.

3pedals

iTrader: (3)

I found the same thing about added timing. The added timing will FOR SURE give it added throttle response, and feel stronger low and midrange(with a big cam), BUT DO NOT use that much timing at torque peak or higher. The reason it likes the timing at lower revs is that the engine is in-efficient at filling the cylinders below the cam's operating range and therefore needs more timing to get the most energy form what it takes in.
I run 38* in mine from idle up to 3500rpm, then I ramp it down to 34* @ 5000. I ONLY run the 34* because my engine is 9.6:1 compression. If your engine has more compresson you will need to use less timing than me throughout your rpm range.

3pedals

iTrader: (3)

Dont be fooled by theEXCESSIVE high timing causing the wideband to show lean, you are headed for engine damage.
set timing to a reasonable level - 30*ish, then get your A/F good, AND verify it with plug readings. Then you can start adding timing untill the plug ground strap shows a good amount of heat discolouring. That is how to tell what is "right" for your combo. Give the engine what it wants - the plugs will tell the story....

Na306StAnG

I guess I'm not explaining my issue correctly.. The car has pretty much had 32 degrees in it since the day I fired it up, as I felt that would be more then a good and safe starting point. The other day when I launched the car thinking the spray was gonna hit and it didn't but the timing was still retarded by 10 degrees the car felt like it lost 200 hp.

Now with my drug like addiction I keep adding timing and I can feel it picking up power but don't hear any detonation... The dyno will tell me what I need to know.

Thanks guys!

ZONES89RS

iTrader: (25)

The denser fuel charge probably allows more timing as well, but the low end timing info was mentioned. A dyno tune will reveal what a engine really likes either way.40 is just allot, and should not make more power but there have been stranger events, showing lean does reflect "leaner is meaner" and may very well be picking up power.

cuda620

Nice Mustang. I have a 94 GT convertable. LS ing it is my next project once I finish my L92/LS3 Jeep CJ. Like the mustangs,,,Hate the motors.

S10xGN

iTrader: (11)

You say the N2O didn't hit, but what about the fuel? If you add fuel w/o the N2O, it'll feel like cr@p for sure. Also, try and remember you no longer have the benefit of a knock sensor loop, and that rattle is sometimes hard to hear. Stock pistons? You'll prolly find that out when a ring land caves in... BTW, love that quote!

Na306StAnG

A blown fuse pwnd me! The nitrous system never worked. I always test my cars on the street before I waste the time and money going to the track but this time I didn't...

Built bottom end! No worries!

speedtigger

iTrader: (16)

I guess I am odd man out. My car runs the fastest at 27-28 degrees. Any more or less and it slows down. But, I have 10.9:1 compression on pump gas. I think the other guys have less compression.

xpndbl3

iTrader: (23)

you also have a small cam and higher compression. That would want less timing, toss some 110 in there and see if you can run more timing and run faster by chance ?

speedtigger

iTrader: (16)

This thought crossed my mind. I have no desire to have to run racing gas, but it would be interesting.

Na306StAnG

Here's one for you guys to chew on... Right now the car has 38 degrees of timing and rolls over and starts like it has 18. Before today it was hard to start and had 20 degrees under 700rpm.. Now cold with 38 it rolls right over like a fuel injected car and idlea with no drama. I'm wondering if something isn't reading right and maybe the MSD thinks Utah at 38 but it isn't.... Anything above 42 and it rolls over like it has to much timing...

Killer5.3

iTrader: (1)

I had a carbed 5.3 in an S-15. I had the best times and plugs looke dthe best using the pre programmed MSD timing chips. The most aggressive one had like 35 degrees total (don't remember which # chip) and that is the one it like best. Stock compression '04 model 5.3 with a 218/220 cam