Taco

iTrader: (1)

OK, here is my current setup.

Stock Block 383 Stroker
Eagle Crank, Rods, Pistons
~11.0:1 Compression Ratio
Bullett Cam-220/220 .540/.540 114 Cam (specs are approx. but pretty close)
Manley 2.02/1.60 Valves
Comp Cams Rockers and Pushrods
Holley Aluminum intake
Stock Manifolds and Cat Back with Flowmaster Muffler

When I go WOT, it pulls very strong up to 4000 rpm, then seems like its losing about 70 horsepower (just SOTP estimate, it falls on its face pretty bad), and it kid of surges, in and out, then about 5000 it starts "popping" through the exhaust, like backfiring, but not just one, it's it's doing it every time the exhaust opens.

I am still running the stock tune, stock injectors and 92 octane.

Is this detonation, bad fuel, need of tuning or something else.

I could see it being the need for higher octane fuel, since the CR is pretty high and no tuning has been done.

Please help me out, I don't want to hurt my new motor.
Thanks in advance!
Taco

mikey

iTrader: (6)

Have you had it on the dyno with a wideband? Or logged any data? Sounds like you are running out of injector at peak Tq.

jrp

iTrader: (16)

especially with the 26# injectors.

and taco, why such a small cam, stock manifolds, and flowmasters

gomer

iTrader: (13)

There are some very smart LS1 people in your area I'm sure if you asked one of them, they would look at the car for you

Taco

iTrader: (1)

Small cam was the choice of my engine guy, he said he talked with the guys at Bullett and this cam is supposed to make really good low-to-midrange torque, which is what I wanted.

The stock manifolds/cat back and flow's is due to lack of funding. Wife, little boy, house payment and accompanying bills don't leave a lot of room for toys, except for my little boy's toys!

I'm working on it thought, hoping to have a little change after we get our taxes back, maybe can get headers and true duals then.

I have not done any logging at all. What do I need to look for if I do wideband dyno pulls? We have a chassis dyno close by, but they don't have any software for LS1's (they are an Impoot based tuner, but will let anybody on the dyno)

That sound like what i need to do (bigger injectors?)

Thanks!
Taco

tdogg5.3

iTrader: (6)

well i think you at least need some 30 lb injectors, and a cam in the 230 range for sure. even a 233/233 torquer cam is on the small side for a 383 stroker from what i;ve heard. and a goooood tune should do the trick

LT99LS1

iTrader: (3)

You need injectors and a tune. Stop running the crap out of that thing till you get injectors and a tune. You can get some used 30lbs(36lbs at 58psi) fords injectors for around $100. Then tune that sucker.

Taco

iTrader: (1)

LOL @ LT. I haven't been running the crap out of it. I ran it for a couple thousand miles before I really even got in it hard. When I did, I noticed it in the middle of 2nd gear, and let out of it.

I ran it up again to see exactly what it was doing, then I putted around all day to make sure the part throttle driving was OK.

Funny thing though, I ran it up this morning, and it didn't do the popping, it still fell off somewhat, but not nearly as bad as yesterday, which leads me to believe it also had something to do with bad fuel.

I still want to get it tuned, but I think it's not as bad as I had thought.

Thanks for the pointers guys, I'm looking for injectors now!
Taco

LT99LS1

iTrader: (3)

Sorry, I should have put that as do not turn the motor that that high in the RPM range till you get some injectors and tuning.

strokedls1

iTrader: (1)

You will do serious damage to your motor with a stock tune and and stock injectors. Most of the heads cam cars that I have tuned are maxed out on stock injector. I usually have to add 10% accross the board on those plus more on wot. Your car will be popping because it is super lean. What is probably saving you is the super restrictive exhaust and small cam. Get that puppy tuned before getting on it again. It is not fun to replace the whole motor from detonation.

Taco

iTrader: (1)

Note to Self: No more Foot-thru-floorboard!

CHECK!

Thanks!
Taco

ktmrider

Hey Taco, I made the same "mistake" on my cam choice ( see sig ) and am getting the EXACT same symptoms. I finally dynoed the truck last month and the graphs looked just like the butt dyno said it would. Pulls like an ox up to 4K rpm and goes flat from there. Some extra tuning got back a lot of the missing top end but also showed me that I am not as skilled a tuner as a builder. Custom tune is coming.
Tdogg is exactly right, look for a cam with duration in the .230 range. Lift will help but not as much as the duration ( gotta fill those bigger cylinders ).
Good luck, enjoy the motor "safely". I totally understand the house, kids, wife, etc. thing!