LT1-LT4 Modifications - 383 LT1 runs 13.30's

So a friend of mine just got his new motor together a few months ago and recently got to the track and his best time was a 13.36@106 with a 2.23 short time on street tires. Heres the mods:

383 LT1 11.1:1 CR
236/242 cam
Ported Trickflow heads with valve job 2.04/1.6 I believe
TSP stg 3 T-56 with spec stg 3 clutch
342 rearend
full weight
Mail order tune by Mad Z

Has all the bolt ons long tubes, Full MSD, CAI, 58mmTB, True duals etc Stock suspension though with tublar LCA's

He knows how to drive fairly well because it ran 13.8 almost bone

I know a big part is his 60' because of the street tires but still a 106 trap speed doesnt make sense, what could be going on here? We know it needs a tire, a better gear and some suspension but like I said 106 don't sound right at all does it???


Here is a clip vs a H/C/I 2V Slostang GT
TA went 13.6@106 on 2.3 60"
GT Went 13.5
http://s133.photobucket.com/albums/q59/hottls1z/?action=view&current=PershallvsBusher.flv

Clearly something ain't right. I got my '94 Z28 down to 13.20's with just bolt ons and BFG DR's. Completely stock longblock and the suspension had been barely improved at that point.

So yes, a 383 with the parts you listed should be significantly quicker and faster. Without seeing the car, putting it on a dyno, and watching him make a pass, I'd be throwing darts at the board.

Need to dyno it with a wideband and a data logger. See what's going on and check the PCM tune thoroughly.

You pointed out the obvious, that the 60' absolutely sucks, but the trap speed is also very low, indicating the motor is not making the power it should, not by a significant margin. A healthy and properly chosen and assembled combo in a 383 LT1 should put down over 400 RWHP easily and result in... I dunno... high 11 sec timeslips? My 385 with CC306 and AFR 195's put down 432/468 and ran a best of 11.30 @120.5

i ran 13.3's with bolt ons and street tires with a 2.4 60! somethings wrong there! my buddy just built a 355 with mild ported stck casting and a small lpe can and ran a 12.2!

i ran 13.3's with bolt ons and street tires with a 2.4 60! somethings wrong there! my buddy just built a 355 with mild ported stck casting and a small lpe can and ran a 12.2!

Yup my brothers 355 using LT1 casting heads is def faster, but you would assume the 383 should be, I'll try to post up a vid

Here is the vehicle in question vs a H/C/I 2V GT
Here the TA ran 13.6@106 2.3 60"
Slostang went 13.5

http://s133.photobucket.com/albums/q59/hottls1z/?action=view&current=PershallvsBusher.flv

what does he shift at? looks like he might not be running his gears up

might be a tuning issue along with either some tire spin....

looks like he is just spinning off the line

Who built the motor? I would get it on a dyno and check the A/F and the tune.

get a dyno tune! and some DR's!

It is all in his 60' times.

with a 1.8xx 60' he would be a 12.5xx

need to dyno it...get it trapping about 120 125 then wonder why is isnt running 10's...its not making any power figure out why

60' isnt what i would worry about now...thats not the problem...cam only cars run 11's heads cam cars run 10's...he needs to trap like hes making power then worry about et

might be simple as fuel pump or filter..tune rockers sensor

I watch one run 13.0s tonite. I did not have the heart to tell him my wifes Bolt on cam car went 13.0s all the time. Or my H/C bolt on car went 11.7s.

It happens. some thing a-miss in the combo just waiting to pop and pull it all together I guess ;)

Get it tuned properly.

get it trapping about 120 125 then wonder why is isnt running 10's

My car traps 125 and has run a best of 11.21 from the previous owner...and he knows how to drive. This sound strange?

It is all in his 60' times.

with a 1.8xx 60' he would be a 12.5xx

Would be lucky to run a 12.8xx on a 1.8 60' Over a tenth for every thousanth is the most he would gain.

driver mod
JK ;-)

what does he shift at? looks like he might not be running his gears up

6000-6200 Revlimiter is at 6200 until a full dynotune is done.

driver mod
JK ;-)

lol I suppose it dont help hes 6'6 240

Are these Trickflow LT1 heads any good? Anyone else running them on this type of combo?

Are these Trickflow LT1 heads any good? Anyone else running them on this type of combo?

oh yes... i have seen some nasty LT1's running the TFS heads... these heads are truely better with boost, they almost seem designed for boost... ... AI's TFS 215 is a nasty head with a good cam combo..

he is way down on power...a bolt on lt1 stock internals should trap at least 106. Figure out why it's not making the power it does. The et is about right for the mph could be a lil lower but its acceptable.

and to wickedbusa
my friends cammed ls1 traps 117-118 and goes 11.7-11.8 so i think your fine you probably could pick up a lil et

He could be trippin the Knock Sensors and it's retarding the Timing.. that would kill a pass..

My Bolt-on Hot-cammed 350ci LT1 with 3.73's on street tires ran 12.5's with a 1.8 60ft..he definately has some problems..

he's shifting too early. i shifted my 355 with cc503 at 6300 which seemed a little early. with a cam the size of his he would want to run the gears up to at least 6500 or so. I kept getting beat my a friends bolton 13.6 t/a until i realized that i was shifting way early(around 6k). we went back out again with me shifting at around 6300-6500 and it was a completely diff race.

He could be trippin the Knock Sensors and it's retarding the Timing.. that would kill a pass..

absolutely - something is seriously amiss in that combo. even short shifting and short times measured with a calendar, that car should be trapping significantly higher than 106.

So....I'm guessing with a full dyno tune instead of the mailorder tune (currently mail order with 6200 rev limiter) a tire, and maybe a little suspension work this should be a solid low 12 sec-high 11 sec combo then?

I would address tires first before I resolved to a full dyno tune and see if he is just really spinning that much.

car should be a solid 11 sec car...when you get the power back that it should have et will come with it...thats why i said mph...et will come with the mph inroovement

Well, I cant see more then maybe 10 mph improvement even with a tire and a better tune. sound right? What are other full weight 383 LT1's trapping at?

yes something is wrong, i would guess hed be running 12s...at least.

something isnt right at all it might not even b a 383 or even the worst build ever stock lt1 or 383.. 80% of these cars have stock lt1 with just simple bolt ons run 13's all day easily so with with this build it should be 11's. here with my car i ran 12.23 at 122mph with stock tires with the drs it way faster. ur build or tune is jacked up get it fixed quik and dyno it as well.

The Teal Car is one of our cars.

http://thumbs.vidiac.com/077f6644-d6cb-48da-80a5-9a99000c3b38.jpg (http://videos.camaroz28.com/video/077f6644-d6cb-48da-80a5-9a99000c3b38.htm)the White car is the Car i was talking about. (http://videos.camaroz28.com/video/077f6644-d6cb-48da-80a5-9a99000c3b38.htm)

That setup is not going to et at all. he is running 3.42 gear and needs to be running a 4.10 with that big duration cam. Also since that cam's duration is 236-240 you should be twisting it to 6500-6700. that is costing the car power!!! Drop that 2.2 60ft down to a 1.8 with some dr's will definately help. Correcting these three issues should drop a full second off the et easily with a good driver!

My old 383 only had 9.8 to 1 compression and it trapped 120 mph.

When I first put it together it ran like crap, the knock sensor was seeing knock ALL THE TIME I desensitized it and the motor acted like I just added 100 hp. We later tuned it with a stand alone AFR logger and made sure it was false knock (it was).

I agree that somethings wrong with the car. He needs to bump up the shift points, probably around 6500 rpms, change the rear gears out to 4.10s. But it needs to be put on a datamaster or something to see what the problem is. Its pretty poor that the car is traping about what a stock car with bolt-ons would. I had a problem with my car not running worth a shit after I got it out, but turns out I burnt 2 plug wires in half. It would idle perfect, but had a horrible dead spot from about 3000-6500. I raced my brothers '94 Cobra with LTs, X pipe, catback, gears and intake and would barely beat him. I replaced the opti and wires and then put in some NGK TR55s and it ran like it should. Could just be something stupid, or could be a big problem.

Let us know what happens though

He must be a horrible driver to pull that time

With that same motor almost (only mine was a 355 with the same cam) I ran 119 in the quarter mile on slicks.... I ran 106 when I had a few bolt ons and entire motor internally was stock. Something is SERIOUSLY wrong..... make sure motor has all 8 plugs where they are supposed to be....

I ran 12.9s with stock ported head and a mild 211/219 cam @111 mph. Haven't been to the strip yet with my 383 combo, but I'll be pissed if I can't do low 12s or high 11s. Something is wrong.

the 60 foot is the main problem, 1 tenth in the 60' is 2 tenths in the quarter. and who ported the heads and what does the car make power wise on the dyno and is it tuned. my 383 with stock heads runs 12.7 @110 with a 2.0 60' (my first and only quarter mile run, the next one broke my torque arm). so anyway i figure a 1.7 60' would net me a low 12 run, which i think is where i should be for stock heads and a 306 cam. (i got ripped off thats why i have stock heads)

so if your friend ran a 13.36 on a 2.3, 6 tenths off of that 60 would net him a pretty straight run.

The 60' is NOT even close to being the "main problem" here. He is definitely down huge on power, probably retarded timing due to knock detection like some people said above.

My 6 speed car with 4.10s, cold air, 1.6 rockers, tune, and very very lightly hand-ported heads trapped at 107mph, and put down 286rwhp (completely stock exhaust including cats).

maybe someone threw a banana peel on his side of the track and he couldnt get traction. it would happen in a cartoon...

Lol.. he caught one under each tire..

lol:eyes: Well plans now are a 28" tall DR and a 9in with a 456 gear and then a full dyno tune so we'll see what happens

He better be spinnin that Engine above 7000rpms for that Gear..

well i think first a dyno tune is in order LONG before he gets any of those parts or gears......

figure out how much power it's got on the dyno. if it's way down throwing a bunch of money and gear ratios at it is not going to fix it. In fact with only 106 mph in trap speed a 28" drag radial is the LAST thing he needs.... He'll bog it so bad it'll cut a 2.7 sec 60'.... and a 4.56 gear is a little steep unless he's got a solid roller cam and some HONKIN heads.....

you guys should take a step back, look at the combo, DYNO it first and figure out where you stand. If it's way low on power tire and gear is not going to solve it. At that point start isolating problems and eliminating possibilities...

I'm trying to save your buddy an a$$load of cash..... 28" DR's, 4.56's and worse timeslips will be expensive....

Dyno tune is a few hundred bucks if that....

So a friend of mine just got his new motor together a few months ago and recently got to the track and his best time was a 13.36@106 with a 2.23 short time on street tires. Heres the mods:

383 LT1 11.1:1 CR
236/242 cam
Ported Trickflow heads with valve job 2.04/1.6 I believe
TSP stg 3 T-56 with spec stg 3 clutch
342 rearend
full weight
Mail order tune by Mad Z

these 2 things are most likely to blame.

these 2 things are most likely to blame.

Well you can make one of them off. The Teal car is the video was going through the traps at 3,840Lbs or so ;)

We also have no idea what kind of driver he is?

these 2 things are most likely to blame.

He refuses to take any weight out of it I dunno why:bang:

[QUOTE=OutlawZ;9366963]well i think first a dyno tune is in order LONG before he gets any of those parts or gears......

In fact with only 106 mph in trap speed a 28" drag radial is the LAST thing he needs.... He'll bog it so bad it'll cut a 2.7 sec 60'.... and a 4.56 gear is a little steep unless he's got a solid roller cam and some HONKIN heads.....
QUOTE]

I dont see why a gear would do anything but help. A 456 gear with a 28" tall tire would be pretty close to the same gearing as a stock tire height and a 410 combo. In fact I had a 95 Z a few yrs back with a 28 tire 456 gear shorty headers and front sway bar delete and a CAI, and a hyper crap tune and managed 12.8 no weight taken out. Worked well for me.:nod: Why wouldnt it work for this car?

Well you can make one of them off. The Teal car is the video was going through the traps at 3,840Lbs or so ;)

We also have no idea what kind of driver he is?

He aint the best driver but not the worst, seems to be average. The main problem I see like many people have mentioned is the mph. There was a stock LS1 Z M6 there the same day trapping 105-107 all afternoon and this 383 should have more then 350 HP the Z has.:confused:

I dont see why a gear would do anything but help. A 456 gear with a 28" tall tire would be pretty close to the same gearing as a stock tire height and a 410 combo. In fact I had a 95 Z a few yrs back with a 28 tire 456 gear shorty headers and front sway bar delete and a CAI, and a hyper crap tune and managed 12.8 no weight taken out. Worked well for me. Why wouldnt it work for this car

Okay so why don't you run 26" slicks and a 4.10 gear and keep some semblance of gas mileage when you are NOT drag racing.... that 4.56 gear is gonna be real fun when he puts his street tires back on... NOT...

If he's trapping 106 a 28" tire will do nothing but bog his motor..... I was trapping 119mph in the 1/4 on motor and when i swapped to 28's my motor bogged..... With a 3.89 gear....

What i'm saying is figure out why his car is only running 106 in the quarter... something is wrong. I ran 106 with near stock LT1 with a few bolt ons.... If he has a 383 with the mods you listed if he's not in the one hundred teens for MPH he either got robbed by his engine builder or something is wrong..... Throwing parts and gears and tires at a car that is 85% probability of having some issues engine related is not going to solve anything but making his wallet lighter....

but it's his car.... if he wants to throw more money at it feel free...

Okay so why don't you run 26" slicks and a 4.10 gear and keep some semblance of gas mileage when you are NOT drag racing.... that 4.56 gear is gonna be real fun when he puts his street tires back on... NOT...

If he's trapping 106 a 28" tire will do nothing but bog his motor..... I was trapping 119mph in the 1/4 on motor and when i swapped to 28's my motor bogged..... With a 3.89 gear....

What i'm saying is figure out why his car is only running 106 in the quarter... something is wrong. I ran 106 with near stock LT1 with a few bolt ons.... If he has a 383 with the mods you listed if he's not in the one hundred teens for MPH he either got robbed by his engine builder or something is wrong..... Throwing parts and gears and tires at a car that is 85% probability of having some issues engine related is not going to solve anything but making his wallet lighter....

but it's his car.... if he wants to throw more money at it feel free...



Well It shouldnt bog down with a 456 gear, theres a big difference between a 389 and a 456. As far as why is because I guess he likes the looks of the 28" tire better and the fact it has more sidewall for better traction. I agree the trap speed is an issue, but I think maybe after a dyno tune so the engine can be revved to the right RPM and getting the car to hook then he should be in the onehundred teens, if not then maybe the engine builder did rob him and maybe didnt port the heads of something...

Well finally got this car dyno'd and tuned and think we figured out a good part of the problem. I dont have the grapg in front of me but I do remember this:
Pulls were done on a mustang dyno.
Origional run-326RWHP
After a few hours of tuning, finally got 394RWHP
Does this sound abought right?
Dont remember the RWTQ but I belive it was around 360-370
If I remember right the peak RWHP was right at around 5600-5800

394 on a mustang is going to bring that bitch to life for sure ;) That would/should/could be around 414 or so on a Dyno Jet.

70 rear wheel is bound to make a differance :D

Peaking so early may be a sign that the heads are not big enough

well there done up trickflows so...?

well there done up trickflows so...?

So they could be as good as stock heads or be really good heads ;)

The bottom line is it's been said here before when you find out what is keeping it from getting the MPH's then worry about the 60' times it should be a low 12 to high 11 second car. If not going for a full dyno tune, I would at least have it run on the dyno to make sure it is pushing close to the power that it should be. This will let you guys know if it truly is a HP issue

well i think first a dyno tune is in order LONG before he gets any of those parts or gears......

figure out how much power it's got on the dyno. if it's way down throwing a bunch of money and gear ratios at it is not going to fix it

you guys should take a step back, look at the combo, DYNO it first and figure out where you stand. If it's way low on power tire and gear is not going to solve it. At that point start isolating problems and eliminating possibilities...

I'm trying to save your buddy an a$$load of cash..... 28" DR's, 4.56's and worse timeslips will be expensive....

Wow guess I was right..... So $300 dollars later and a few hours and your buddy found 70hp..... So I saved your buddy about:

Two 28" DR's-about $400 ish
4.56 gears plus install-$500-600

tell your buddy to just mail me a check for a grand and we'll call it even... :D

I agree. 70 horsepower for $300 is a darn good investment. :D Like was said above now he can work on the other things. Even with the weight he should have a low 12 or high 11 second car.

well id deff check the knock sensor first of all. and second making power is all in the combo. you could have the best parts in the world but if they dont work together its a waist of time. a high rpm part and a low rpm part together do not equal best of bolth worlds