Ken Jarosz

My LT4 recently posted runs on a Dyno at about 300HP. Does anyone know what the factory HP specification was on this model at the back wheels or have comparable data for a stock LT4?

scorp508

I have seen in person stock LT4s do 300-305 at the wheels. The facotry HP spec on paper is 330hp at the crank. It is an obvious lie that was made and all but confirmed by GM so that the early 345hp LS1s in the C5s wouldn't be outshined. :yesnod:

GS Ragtop

Stop by the LT4 dyno posting page at Hutch's site: http://www.hashmarks.com/dyno_page.htm. It shows the dyno charts for a few LT4's with a wide variety of modifications.

Mine is the last on the list - it's stock except for Corsa exhaust and a K&N filter. Dyno read 308/308 in air thick enough to cut with a knife (85 degrees, 100% humidity). :D

Brad

Mez

I highly recommend checking out http://www.lt4.com site. It really does a thorough job of detailing the LT4 engine.

Check out the link in my signature to my home page for graph of my LT4 before and after head porting.

Shriker

As all of these guys have said , there are some good resources for info on LT4's. I have seen roughly 10 stock dyno sheets on LT4's and the lowest I have seen was 285 and the highest was 305 with the VAST majority in the 295-300 rwhp range. This is almost identical to 97-00 LS1 dynos all throughout the rev range.

I have not put mine on the dyno yet (only had the car a short time) but will soon.......I expect around 295+.......... :seeya

vader86

Good numbers, the GM number was 330 crank, but yours and others prove that its more like 350 crank.

NavyVet

Mine dyno'd 306.7HP and 308.9TQ when it had: 62K miles, muffler elims + K&N w/open lid and no other mods. This was on a old (+/- 5 years) in-ground DynoJet on a 93 degree day with humidity of approximatley 30%. This did not correct for elevation of approximately 1,320 feet in Phoenix. So, I guess that's typical.

cesar

my 92 Lt1 dyno 299hp and 333 rwt at mustang dyno.
zz9 cam shorty headers,tpis pipes whole no conv the claw intake ed wright chip rev to 6500rpm very flat torque 4100 to 6200 rpm is not a LT4 but it sounds good


[Modified by cesar, 11:12 PM 5/22/2002]

cesar

made error on the torque i up dated the info soooooorrrrry

LT5

:cheers:

rcolling

Here is the dyno of my stock LT4 with 54,000 miles on it.
It is going back to the same dyno on July 13 with the SLP Claw intake and Corsas!

Ken Jarosz

Thanks for all the LT 4 Dyno results. Looks like mine is right there with all the others. Seems like all the commercial "wonder packages" like exhausts, filters, chips, etc. do not generate much improvement on the LT4 motor performance.

TIMSPEED

I witnessed a 96 LT4 pull around 330rwhp and 300 and some change rwtq. It only had like..open air lid and Mufflers literally CUT OFF. Pretty damn impressive!

mackeyred96

They are great motors. :yesnod:

rcdk

:eek: :eek: Isn't that getting up into ZR1/Z06 territory?

MSR

mine was bone stock when it pulled 282rw. upset with the result, i put a fresh air filter and plugs in it, and reset the ecm. it then pulled 291rw.

then i removed the maf screen, 291. then i cut the airbox lid open, 291. then i installed the magnaflow rear exhaust kit, 291, plus a whole bunch of drone.

at least my attention to detail makes for consistent dyno pulls!



[Modified by MSR, 9:27 PM 5/24/2002]

LT5

They have always been there.

Mez

Stock ZR1s are in the 325-340 rwhp range. I think the Z06 are in that area also but I am sure someone in the C5 board will let you know.

The Green Rocket

rcolling, your dyno graphs show that something needs attention: either you are getting some spark scatter from a carbon tracked opti distributor cap, or you need some more fuel trim from about 4,200 rpm onwards

The LT4 is one of my favorite engines, many people mistake mine for an LT4 because I painted the intake, and added GrandSport emblems and hash marks to the exterior (people always say: "hey, I don't remember ever seeing a green GrandSport before").

Tomorrow is dyno tuning time for me again (I rented the dyno for two hours). I had an extra bung welded in ahead of the catalytic so that I can insert a wide band air/fuel ratio sensor, and I'll have a gas analyzer in the tailpipe. I'll be playing with LT1Edit, a self directed programming software program to work over the spark and fuel curves. I'm not expecting to see any real increase in top end power (although I'm not so secretly hoping to eclipse 370 rwhp). My main goal is to fatten up mid range torque - I really think that another 10 to 15 lbs of torque is in there waiting to be discovered. I'll report the results no matter which way they go.

Thomas

rcolling

Thomas,
I had noticed the jags at higher RPM and wasn't sure what to do with them. I know I want to put a Fuel pressure guage on it. How can I check/clean the opti for carbon?