Got the results.. I was hoping for more.. after 8 pulls... (this was pull 8)

268rwhp @ 5100 rpm (assuming 18% drineline loss - 318 fhp)
324rwtq @ 4000 rpm (assuming 18% driveline loss - 382 ftq)

The dyno is a Eddy Current Dyno.. the operator indicated dynojets yeild about a 7%-10% increase in numbers.. but i'm not too concerened about numbers.. as much as the nice flat curves I got for A/f, HP and TQ.

but A/F was dead on nuts between 12.5-13.1 from 3000 (test start)until around 5400rpm then it got pig rich (10.8:1) the Cat Overtemp switch flipped at the same RPM

the inital few runs while we were tuning the car the CATovertemp didn't come on and all was good.. including the a/f.. we looked in the ECM .dat file $DA2 for the switch to turn cat overtemp off and it isnt there.. we emailed the guys at tuner cat and are going to see what they say about disabling it.. but i dont think it will make a differece since the hp was already falling off before it went pig rich.. we ran the car in 2nd gear to double check on the AFR in the 5400+ range at WOT the A/F was perfect 12.5-13.1 .. catovertemp didnt activate on that test for some reason - maybe the ECM doesnt add the extra fuel to cool the cat in 2nd gear..

Anyways, if you guys have any idea how to kill the ECM richining the mixture for Catovertemp my ears are open..

BTW:
Engine specs
383 LT1
Stock heads, rocker arms, exhuast manifold, AIR pump and full emissions (except no cat converters).
10.8:1 KB pistons, Comp cam (see sig for specs)
everything else is BONE stock..



This is the place I went to.. Dave is excellent to work with and knows his stuff! I would recommend them to anyone in the jax, fl. area!

 

Those type of dynos are heart breakers.. You should take the car to the track or put it on a dynoget dyno.

What did you do for timing? sounds like you got the fueling pretty close.

 

timing was good.. it was jsut pulling .1-.5* from 3000k-5800k... seemed to be spot on. I'll be tracking it this month down at our closest 1/4 mile (gainsville fl) to get some trap speeds/ET's.. I'll post more results as I get them.

Yea.. thats what dave was saying.. run dynojets for bigger numbers - I guess the are a little more liberal.. Supposedly this is a Lab grade dyno.. we used Lamda Wide band sensors etc..with magnetic resistance for the drums.. all and all it was a cool experiance.. a little nerve wracking when you see and hear some of the stuff you do while standing next to your car exhaust at WOT.. after the first pull and you get used to it.. it is AWASOME!!

I'm going to slap on a set of LT headers and some 1.6 RR and go back for some adjustment.. and pulls..

 

Yeah you really need a set of headers. Really open up the filter side of everything too.


I'll bet a set of headers in your car would pick it up about 40rwhp

 

What do you mean "really open up the filter side"? As in 52mm TB, Cut lid, etc..etcc..?

 

Well let me break it down for you so maybe you'll feel a little better.

A stock LT1 6-spd makes 270 rwhp and 300 rwtq on a dynojet.

An automatic transmission will make less. An eddy current dyno will make less. The fact that you were able to make basically the same horsepower and MORE torque would imply that your car is making quite a bit more power than a stock.

The 383 is great but here are a few things.

Stock air filter? Restriction go with a K&N and open air lid (it was worth 11 hp on my modded Head / cam LT1)
stock throttle body - probably worth some restriction but do this last
stock heads - major restriction, worth 30+ hp on a 350, worth more on your stroker
exhaust - major restrction, long tubes are worth 20+ hp and 30+ tq on an 350, would be more on your 383
rockers - coupled with stock heads, major restriction worth 10 HP on a stock car. On my car 1.7's were worth 14 hp over 1.6's on ported heads.

It sounds to me like you've got a great baseline to start making some serious power. It's just a matter of how fast do you want to spend, er um, go.

 

nathan - thanks for the words of encouragement.

I already have a K&N air filter.. but not a cut lid.. maybe i'll do that tomorrow..

throttle body - Its my understanding that the GM crate engine 502 ram jet uses a 48mm TB as does the LT4... I'm not really sure i'm conviced I need this.. but as my dyno numbers indicate.. maybe i do.

RR & LT's = I think this is my next step next week.. now if I can only find a set of normal heders for the LT1.. I dont need any fancy coatings.. I would LOVE some el-cheapo LT's.. however, it looks like ceramic coated are the only option (except for Stainless..). Oh well.. guess I'll have to go stainless..

Heads...... yea... heads..... this is my daily driver, as I have a *****-to-the-wall 1978 T/A drag car.. which is where alot of my money is allocated.. I've seen alot of good heads for the LT1 - but it seems porting the stock LT1's is the best route.. (wifey - are you listening.. maybe a xmas gift?) anyways, in all reality the cost of the heads isnt a big deal.. but the time to install them... again.. I should have done this while I had it apart.. dam hindsight!

The thing i'm worried about most.. which i've posted in another thread.. is that once i do all this work.. the stock tranny and D36 rear end will go - BOOM! this is what happened with the T/A when I first started playing with it.. first it was bolt ons... than stroke/bore.. than a full on race motor.. before i knew it I blew 7 trannys before i found the right built (and extream cost) for one that held togeather.. then the rear end SPLIT the carrier bearing race.. SPLIT THE RACE! so that needed to be upgraded.. then the car ran so fast it needed mucho safety equipment.. then at that point it wasnt something i was gonna drive to work.... so I bought the vette.. I guess its an endless cycle... time to start looking for a new work car.. maybe

 

I found out a long time ago that it's cheaper to buy a car that was made for racing rather than keep throwing money at one that was made for the street, if you look in the back of a national dragster you will see that you can buy a altered roller( complete minis engine) for $7.500-$12,000. With a mild b.b. you can turn 8.50's 1/4or 6.00's 1/8, it will run in pro or most of the super classes. joe

 

Dynojet eddy current dynos in my view reflect the most accurate HP/TQ, and AF data on the market. To me, it seems all the other dyno manufactures/operators have something to say but to me the Dynojet dynos are accurate, very accurate. What you seen on the screen is what you got. Agree, take the car to a Dynojet

 

Blu - cut the lid for the k&n

Then go to the track, not just once but a few times.

The numbers you'll see there will make you feel better.

IMHO - the eddy current is the way to go for custom tuning for the entire rpm range.

You dont need a 52 mm TB with the stock exhaust manifolds, save you money to do the heads, LT's and TB at the same time, them go back to that dyno and retune.

 

I don't know about htat.. The eddie current dynos that I know of here are constanly reading way out of wack. one of them the guy told me he "tuned" to read like a dynojet..

That scares me because if he can alter the readings.. whats to say he won't alter them to show that gain in HP after a tune or something. Supposively this one has a **** you can control load with.

 

Not so my friend with a Dynojet Dyno. Have you operated one? If not, go talk to a tuner who owns one. Dynojet is real picky on their new dynos and their reputation.

 

I think you misunderstood what I said. theres a guy here with a dyno-dynamics dyno and they have said they can adjust how the thing reads.. thats what scares me. They said that they adjusted theres to read like a dynojet..now.thats straigth from the horses mouth...The person that owns it... Whats to keep them from adjusting hwo it reads to influence the HP gains? We are already suspecious of them becuase they are getting like 25 hp out of intakes on nissain z's and things like that... We dont' care because all they deal with is import crap but still I was making a point.

When you run a car on a dynojet dyno it spits out numbers.. theres nothing you can really do to alter it or anything.


Oh and you can say that I have a bit of experience on the dyno-jet..

 

Alvin,

Hell I know you do. I watch what you tell folks in this forum right from wrong. It's people like you that make this forum what it is today.

 

Man i tell you to be honest.. your responses confuse the hell out of me.

 

Man i tell you to be honest.. your responses confuse the hell out of me. I have no idea what your trying to say to me here.

 

The **** thing can be adjusted to simulate road resistance, grade increases and such, so theoretically some mook with one can give ficticiously high readings by lowering the load put on the rollers.

 

Most of the available dynos out today have a way of adjusting the numbers if so desired. These dynos include Dynodynamics, MD, Superflow, Dynapack, Land and Sea, and Dynojet. It is very simple just change the correction factor.

I agree with Alvin on the specific point of people adjusting the result numbers to show larger gains then what they may actually have seen otherwise. There was a big debate about this awhile back. Certain shops/tuners were accused of changing correction factors or changing the placement of the intake air temperature probe to acquire better numbers to show bigger gains to cover the fact that they were not tuning the vehicles properly in the first place.



Chris Macellaro

 

Hey hey hey don't go blaming Alvin for this mess.

 

DynoDynamics has this **** on the hand held controller. It is used to adjust the amount of load placed on the car by way of magnetic resistance through the eddy-current retarders. It allows you to hold the vehicle steady state at any speed and use the throttle position to change manifold pressure. This allows the tuner to place the ECU in a given load cell for as long as necessary to adjust fueling, timing, exc. This also allows the user to change the ramp rate (acceleration rate) of the vehicle. This in turn allows how quickly you allow the vehicle to accelerate more accurately repeated like on the street or track. But as jd_v3tt3 stated in the wrong hands a dishonest operator could place less load on the vehicle in a back to back run and show a slight power improvement. Makes you wonder now doesn’t it?



Chris Macellaro