results of first shakedown runs with LS1 - Third Generation F-Body Message Boards

mw66nova · 07-04-2009, 01:01 AM

ok, we got some decent data that is gonna help us make some changes. the car did well for it's first outting. actually, faster than i'd ever been before, but still left me realizing that there is some being left on the table:

the car is running into the limitter (set at 6500)on the 2-3 shift and then about 50ft before the stripes it'll bounce the limitter again, so i know it's gonna need less gear. i'm thinking a 4.11 would be best so that i have a little room to grow.

the first run seemed like a straight throw-away wtih a 12.46 @ 108 on a 1.66 60'...i screwed up and didn't save the log either, i was pissed. i drained all my 93 octane before the runs to put in some 101unleaded to see if my knock issues went away. during the run, i still noticed that it was pulling 5*, which it shouldn't have been doing...so i'm thinking that the knock issues i'm seeing are straight up false knock.

consequently, i turned the knock sensors off for the rest of the night to see what she'd do with that. yeilded desireable results as the car picked up at went a 12.30 @ 109mph on a 1.63 60' bouncing off the limitter on the 2-3 shift and pedaling it twice.

the way i have the fuel lines run they are awefully close to the exhaust system, and i'm thinking i'm running into some kind of vapor lock issue or something. after two passes, the pump started to cavitate on the way back to the pits and then the fuel pressure went to 0, air fuel went way lean, and the car cut off. it acted like it ran out of gas, but with a half tank of 101 unleaded, i knew that wasn't the case. i pulled the fuel filter and it was clean, no problems with the filter at all actually, but the fuel that came out of the line was HOT to the touch, so i'm wondering if i'm running into some kind of strange vapor lock issue due to the routing of my lines.

we put a little fuel in the tables because it went lean on us(i didn't put the two together with the fuel pump cavitating). the fuel pressure gauge was rock steady so i figured the fuel had cooled off enough. the car went the fastest of the night with 11:1 a/f ratio, lol! 12.15@110mph on a 1.628 60'.

when i saw the a/f was 11:1, i told my buddy ben that we needed to pull the fuel back out that he added, so we did that. the fuel pressure gauge was staying steady so we rolled back into the staging lanes for what i thought was going to be the fastest pass. the car came out of the hole faster than it ever has with a 1.59 60', but as i went down the track the a/f started going lean...it ended up right around 14:1 before the end of the track, and i noticed my fuel pressure gauge starting to flicker again. ugh...12.40 @ 107mph...and now the car has a funky miss at part throttle that wasn't there before the last pass. i'm hoping it something simple and stupid like a spark plug/wire/vacuum leak or something....the weird thing is that it's not there at idle and the car still free revs easily. i'm going to pull the plugs and do a compression check this weekend, just to be on the safe side.

hmm...wonder if i broke one of those weak ls6 springs? lol! i'll check that too in the morning.

all in all it was a great first trek out with the new combo, and the car pulled the tires off the ground every pass, one of the guys said both tires were like a foot off the ground! so i think i'll pull some gear out cause i'm putting everything to the ground on the bottom end of the track, where as i need to get it to put it down a little better up top.

oh, and the car is far heavier than i figured it'd be. 3375lbs with me in the car...3085lbs without me, that's with a little over half a tank of gas.

gtpro700 · 07-04-2009, 01:10 AM

Nice times for the first time out! Fix those few little problems and you should be easily sitting in the 11's with a pretty mild build. Like always nice job and the car is awesome. Cant wait to see the new results when all is worked out. What are your future plans for the motor after you get it all dialed in? Are you planning on putting a bigger cam or doing any work to it ? Again, nice job man!

mw66nova · 07-04-2009, 01:16 AM

future plans include an iron 6.0L and a set of L92 heads....this motor is just to get the car setup for the lsx world, lol! maybe a little shot of the giggle gas and a stouter set of valve springs so i don't run into valve float or risk tearing anything up.

Fast 383 · 07-04-2009, 08:10 AM

Want to trade user names?

jbenge · 07-04-2009, 09:52 AM

Good results for your first trip to the dragstrip with your new combo. LS is definately the way to go, I'm planning on buiding a carbed 408 combo in the future similar to what stage20 has.

mw66nova · 07-04-2009, 10:20 AM

ok, so i pulled the valve covers, everything is working correctly under there...the plugs look good too. number 3 and number 6 are much whiter than the rest, they look lean actually, but the others look great...i'm gonna run a compression test after work...still has a wierd slight miss to it though.

i also calculated my converter slippage to be 14%

DIGGLER · 07-04-2009, 11:10 AM

nice! good set of baseline passes to get started with.

xpndbl3 · 07-04-2009, 12:21 PM

nice job out of the gate, if you need any tips for those funky ls1's at the track let me know. my car doesn't pull the tires at all out of the gate, in fact the nose barely lifts up. So I wish I was yanking them a foot

4.11 gear here but with 28" slicks it's too little gear to be optimized for motor trap rpm, but fine for a nitrous setup.

see what i mean, wrinkles the tires but the nose just moves up an inch or two and away I go.

mw66nova · 07-04-2009, 07:22 PM

steve, can you pm me with your trap mph and rpm? i'm trying to pick a new gear and i'm stuck between 4.11 and 4.30

update, plugs look good, valve springs look good, compression check is good, put everything back together and it sounds perfect again...must have been a loose wire or something! i'm just so stoaked that it's not something major. got a lot of little things to tackle before going back out, and rebuilding the motor is not one of the things on that list, lol!

no launch pics, but here's a cool burnout picture!

xpndbl3 · 07-04-2009, 08:47 PM

sending a pm now

brandoz28 · 07-05-2009, 02:48 PM

what trans are you running? a 4l60e? if so, your first gear has gotta be NASTY short.

mw66nova · 07-05-2009, 04:15 PM

yup, 4l60e, starting line ratio is 13.96:1, lol!

KWIK84 · 07-05-2009, 05:18 PM

Are you still injected??? If so that could be the cause for your slight miss under power and ok with free revs. Especially if you said you had 2 cylinders showing lean. After taking some stuff apart and putting it back together could have dislodged whatever is partially blocking the spray nozzle. Just a FYI.......

mw66nova · 07-05-2009, 05:35 PM

yup, i'm injected now. i didn't take the injectors loose when i took stuff apart, so it couldn't have been that. not sure, but glad it's back to normal, lol!

brandoz28 · 07-05-2009, 05:46 PM

i bet thats a riot taking off! 4.10's and a dying 700r4 was pretty fun for about 10 minutes...then that old 700 gave up the ghost!

xpndbl3 · 07-05-2009, 07:24 PM

Quote:

Originally Posted by mw66nova

yup, 4l60e, starting line ratio is 13.96:1, lol!

no wonder it's leaving like a beast.

ZONES89RS · 07-05-2009, 07:59 PM

Not bad, what all is done to the LS1? SO close to 11s, i bet you cant stand it!

Shagwell · 07-07-2009, 09:50 AM

Good solid numbers for what it is and a good baseline to work with.

daverr · 07-07-2009, 09:15 PM

Quote:

Originally Posted by mw66nova

blah blah blah, my 305 made 243rwhp and went 12.3x's...450hp should be way faster than that.

u mean your only a couple tenths faster with the ls1?????
doesnt seem like much of a upgrade from the 305. weird

your cam might be off a tooth.

mw66nova · 07-07-2009, 10:06 PM

yup, it's two tenths quicker with me pedaling it, boucing off the limiter on all gear changes and through the traps, and still has the stock timing tables, in air that is 2000ft worse than my 305's best time, had i made the passes in the same kind of air i ran the 305 in, the car would have gone 11.84 at 114mph...oh, and has managed 20mpg mixed town and city, the 305 would only get 8 at best.

don't be a duechebag, it's the first time out with the car with this motor. i have no tune in it yet and it still went faster than anything else i've ever had. this weekend showed me alot of things to address that will help out a bunch to get this car quicker. this motor isn't even a super wild combo, it's got a camshaft in it that's only slightly stouter than an ls6 camshaft.

my 305 went 12.38 @ 108 on a 1.63 60' time in good air and was completely optimized after two years of working on it.

the ls1 is brand new, first weekend out with it, untuned, overgeared, and have a problem with the fuel system...

apples to oranges my friend.

xpndbl3 · 07-07-2009, 10:12 PM

you mean a small cam only swap with stock heads doesn't run 10.80s first pass with it? LIAR! what a comment to be made by the other guy.

ZONES89RS · 07-07-2009, 11:12 PM

What kind of headers did you use?

xpndbl3 · 07-07-2009, 11:33 PM

he has the super expensive hawks ones

Orr89RocZ · 07-07-2009, 11:34 PM

Give it time and it will come. Not a bad first outing... wish it could have went smoother for you but oh well, it will come.

3/6 cylinder lean thing is kinda funky, look into those injectors to start. Keep tweaking the fueling and that car will pick up alot.

zz17iroc · 07-08-2009, 12:10 AM

Quote:

Originally Posted by mw66nova

we put a little fuel in the tables because it went lean on us(i didn't put the two together with the fuel pump cavitating). the fuel pressure gauge was rock steady so i figured the fuel had cooled off enough. the car went the fastest of the night with 11:1 a/f ratio, lol! 12.15@110mph on a 1.628 60'.

when i saw the a/f was 11:1, i told my buddy ben that we needed to pull the fuel back out that he added, so we did that. the fuel pressure gauge was staying steady so we rolled back into the staging lanes for what i thought was going to be the fastest pass. the car came out of the hole faster than it ever has with a 1.59 60', but as i went down the track the a/f started going lean...it ended up right around 14:1 before the end of the track, and i noticed my fuel pressure gauge starting to flicker again. ugh...12.40 @ 107mph...and now the car has a funky miss at part throttle that wasn't there before the last pass. i'm hoping it something simple and stupid like a spark plug/wire/vacuum leak or something....the weird thing is that it's not there at idle and the car still free revs easily. i'm going to pull the plugs and do a compression check this weekend, just to be on the safe side.

Hey Matt, what's up Bro. It looks like you have a nice sleeper!
It sounds to me that you may have an injector issue? You said earlier that you pulled all plugs and two of which were a little white. My 02 Yukon had the same issue with cylinder number 5 so I swapped the #3 and #5, then pulled both of those plugs after a day of normal and hard driving. Guess what? The problem moved from #5 to #3. So when you added that fuel it changed the injecter pulsewidth timing openning the injector longer resulting in a richer AFR. The injector maybe openning a little late at the lower pulsewidth and sticking openning at the higher pulsewidth. If you think about it, that is why it's lean with your original tune and way fat when you added fuel? Just a thought anything is possible when dealing with fuel injection. Find a buddy with known good fuel injectors and swap them out if you can.
I could only afford 1 injector from GM parts direct to fix my truck, costing me $96 dollars, just for 1 because it is flex fuel.

Well I hope this helps, but if you need anymore help tuning PM me?

Craig

mw66nova · 07-08-2009, 06:39 AM

i've got a set of 36lb-ers lined up already. they are accel and have 8k miles on them. i trust the guy i'm getting them from so hopefully they'll help out.

ssean92 · 07-08-2009, 06:54 PM

I wasthere for the shake down run and it was fun to see the cr launch. Hell it was cool seeing it run that 12.1. Congrats on the inital shake down. Now get it tuned up so we can line up...LOL

chikn305 · 07-08-2009, 10:36 PM

Congrats on the shake down runs. Some tuning and better weather that thing will run some good numbers. I had a buddies ls1 car we were tuning and to get it to shift without hitting the limiter we set the shift points 500 rpm lower than where we wanted it to shift.