ive about had it with this damn thing. Please give me some insight to what is wrong. First off this is a speed inc 382 stroker. Its about 2 years old. a buddy of mine bought it from them, put 4k on it and wrecked his car. sat for a year then I got into ls1s so bought the whole car for the motor. I put it all together in my camaro and went to the dyno. Here was my list of mods

fully forged 382 stroker shortblock 11.5:1 compression
headstuds, main studs, arp rodbolts
????stage 2 ls6 style patriot heads???(now leaning torward maybe too small of a head so MIGHT not be the stage 2's. says ls6 and patriot on the heads and can tell they have been cnc'd but not sure on flow numbers.)
patriot GOLD dual spings
comp r lifters
7.400 hard pushrods
232/232 112+4 comp cam
stock rockers
slp pump
double roller timing chain
Typhoon Intake
ported stock t.b.
flowtech 1 3/4 headers
flowtech y
borla catback (open)
lid
filter
yank 3800 verter
auto
10 bolt with 2.73's


after all tuning was done it put down 38x hp and 379 tq.
SO I was very disapointed. dyno graph just went flat at 5200.

Dont have this graph anymore.....

Then I put in the stock verter/tranny, cutouts after headers, ls6 intake, and 3.42 gears. Went back to the dyno and came up with this graph


Red line is cutout closed no air filter. 397.99 hp 400.83 tq
blue line no filter, cutouts open 408.53 hp 409.26 tq

also very disappointed agian. basically just picked up what ever power was lost in the verter IMO.

SOOOO I went home, put in a 240/248 112+4 comp cam, set the preload right on the comp rs with 7.325 pushrods, installed 42lb injectors, and 85mm z06 maf still with stock converter.

Heres what i came up with....


401.36 hp 396.04 tq

graph goes from 275hp to 400 in 25hp increments
graph goes from 3.75 to 6.5 rpm in .25 increments (just for referance)

only got to make 1 run today since some how my tranny tailshaft broke causing a leak. (heard it happens some time with steel driveshafts) it could have picked up a little with tuning more but still has a flatline at 5400. also is peaking hp around 6000-6200







Sorry about the graphs beening shitty. some reason my scanner wouldnt work and had to take pics of them.

PLEASE GIVE ME SOME SUGGESTIONS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

this motor should peak more around 6600-6800 what is the deal???

Only 2 things I can think of..... Valve float(doubt but will be yanking one bank off to check seat pressure) or heads arent flowing enough.

Any suggestions is very well appeciated!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!


car has been tuned well with good a/f and 30* of timing. only has 1* of knock arond 4800 and goes away before the end of the run.

 

sounds like these are the old patriot heads that are considered to be behind the time in comparison to their current CNC heads. i believe they changed the CNC program on them in the last year and those heads are really performing well now. sounds like you need change your heads out and sell the old heads on a budget price for someone else to use as an upgrade over 241's.

have you done a compression check on all the cylinders?

240/248 cam is a nice cam that is what i almost went with for my 403 that cam can make the power swapping to the LS6 intake should have made a difference but doesnt look like it did at all. unless those headers are backing up flow

a 382 should definitely be making alot more tq and hp than this one is.

also is it possible that the cam has too much timing advance on it?

on my 403 im running 23x/24x .60x 112+2, -6 on the cam sprocket, 116 ICL, retarding the cam has proven very good results and a ton of power under the curve, tq is fat and broad and hp is linear all the way to 530-550 whp on other 403-408 builds. my car will be done wed, it should perform just as many others have as well. i was told by Dave' Total Performance who designed the cam, on stroker motors to retard the cam on the install.

 

do you think this cam is to advanced??? I chose this cam because this is a nitrous motor. I plan to spray a 175 shot as soon as I figure out all of the bugs. I think this motor should put atleast 430-440 through the stock stall. If I was to retard the cam how many degress do you think I should do. Ive always understood it as advancing and retarding the camshaft only moved the power band up top or down low.

 

Here is your graph from today. I have all your files on my comp so if you want any others posted, let me know.

 

this motor was bought in late of 04. not sure what heads patriot had out at that time...

 

ttt ttt

 

Comp r's and stock rockers are part of your problem. You can work the preload a little by adjusting the pushrod length but in the end those lifters are really made for adjustable rockers. I'd bet going to standard lifters will help up top where it's flatlining.
As for the cam, the 240/248 is more inline with what you need. In terms of the degreeing a 112+4 should be fine so long as it was installed correctly, dot to dot. That cam installed properly should not hurt you.
Start small and only change 1 thing at a time to track down your problem. I think you should start with the lifters and then put the proper pushrods in based on your setup.
On a side note, the LS6 intake will do alright for you in the setup but once the bugs are worked out that will be your limiting factor.

 

comp rs have been set perfectly. dont need adjustable rockers. they have .003-.005 on all rockers. comp says they need 0-.005 of preload. I had a 7.400 pushrod in the first graph... .080 of preload on them. changed to the 7.325s and seat of pants was a ton better. seemed to hold the front of the car up all the way through the gears but dyno showed no improvement. the typhoon and ls6 intake is performing the same since there has been almost no change between swaping them.

 

Are you checking preload with adjustable pushrod or figuring it? If you're not checking it, your calculations may be off. If you are, I'd still change out to regular GM lifters or Comp 850 OEMs to eliminate that.

But, more than likely, it's a combination of the springs and lifters. The springs may simply be too old now, especially if the motor sat for a year.

With Comp 977, the same thing was happening at around 6200RPM with big valves... the spring pressures open and close were enough for the cam and valves, but the harmonics were screwy and it flatlined. If the springs were floating, it'd look different, so I'm not saying that. I'm suggesting the springs may have lost some of their harmonics due to age and sitting. Did it sit in the weather at all? Extreme cold for any length of time?

Swap out the Comp R 875s for the 850s. Then put some new Patriot Gold springs on there if the lifter doesn't do the trick. At most, you're looking at $300 and your time to see if you can get it to pull past 6k.

 

Do springs go old?



What kind of springs are you running?

 

car sat outside for a year and a half under a cover.

 

For Reference... My Lunati 383 Stroker with Comp Cam XE-r 236-240, AS LS6 Stage 2 heads, 977 Springs, Comp R lifters, LS6 intake and TB, 85mm maf, ASP Underdrive Pulley, Mezeire EWP, A4 with a TCI 4400 converter, Moser 12 Bolt with 4.11 put down 459rwhp and 430 rwtq.

 

Super pure chrome silicon can fatigue over time just like any other alloy (but it's designed to handle cyclical changes really well and stand up to fatigue and heat). For harmonics to be screwy, the surface needs to pit ever so slightly. Add in the Comp R propensity to cause headaches, and you have a starting point to at least look.

Also, check the cranking compression and do a leak-down if necessary. Make sure you don't have any corrosion on the rings.

 

Replacing the heads with better ones and raising compression would help a lot.

Replacing the typhoon and stock ported tb with a 90/90 would add a lot also.

Just those two things combined would make it an entirely different car.

 

I dont want to throw parts at this motor until all the bugs are worked out. (unless those parts are needed to work the bugs out) All I want is a nice smoothgraph with atleast 430rwhp. I think that will take me to the 10.99 or better na Im hoping for.

 

I wouldnt give up on the heads, I saw and drove a c5 with a 408 that lt1 dave built with patriot stage 2 heads with 2.02 1.60 valves put up 530 rwhp. its on here somewhere. Inexpensive does not mean low quality, it usually means more go fast parts.

 

how recent was that? cause that sounds like the car he told me about and sent me a dyno graph on which is why i chose his cam for my 403 and his ported fast 90.

im not knocking patriots, i have read that the CNC job this last year has improved drastically. i was going to run a set of stage 3, 2.08/1.60 for $1095 when they were running the special. I got lucky and picked up a set of Dart 225's locally from a friend for 1k, they had 1200 miles on them. Got the flow sheets on them as well. he is now running a test set of darts that were hand ported by dart and will become the revised casting later this year.

 

the cam im running is a DTP stg2 from lt1dave 238/24x 112+2 installed -6 on the cam sprocket, i believe you are correct by saying retarding the cam shaft brings the power in earlier, but from the dyno graph i saw from dave the torque came in earlier and the power deliverey was linear like a SC would look like all the way to 6800, they spun the motor to 7200. Ill probaby go up to 7k.

i would start with the small things like suggested, lifters, springs and work up from there. at this point the power from this 382 looks like heads/cam 346's.

if you got a great deal on the motor and you have seemed to work many of the bugs out, and if your going to spray it, then just F-it, put the bottle to it, throw some tires on it and take it to the track and have fun!

 

I actually ended up with this motor, borla, and a ramair hood for my ta for free after parting out the car and selling my stock motor so Im not bummed on having to spend money to work out the kinks BUT I would rather know exactly what is causing this so im not just throwing parts at the thing.


I talked with gunnar at patriot today and we have figured out that these are mid 03 stage 2 ls6 heads. He said they flow the same but have a 240cc runner instead of a 227 that they have now... I know that is costing me a bit of power but not causing this problem.

Also talked with Ed Wright today on retarding the cam and he allowed that he runs his cam +4 advanced in his stroker lt1. car runs 10.teens and as everyone knows he knows his stuff. BUT alot of things are differnt on the way lt1's and ls1's react to mods so Im not sure if I should bring mine back down to 0 or leave it at the +4 it has ground into it.

 

well let the car sit for a day and then took off the rockers. 10 out of 16 lifters would give when pushing down on them.the others stayed solid. put everything back together and it took a little while for them to all pump up(could hear rockers tapping). one stayed tapping until I hit 6k a couple times(while driving). Maybe in the lifters. I know when he had this motor in his car with the original 232/232 595/595 cam it thumped alot harder then what it did in my car. A few dead lifters would deffinatly do that as well.