zims350

well got the car put together and dropped it off at speed inc for tuning, car put down 390/358 to say the least I am not happy.

98 ss m6
patriot stage 2 ls6 heads
tsp 231/237
pacesetter longtubes
ory loudmouth catback
10 bolt 3:42

after tuning car still surges a tad, and hunts for idle sometimes. The dyno graph looks similiar to cam only 231/237 cars. I bent a couple of valves on the stock heads and put these on, so I am going to check compression on all cylinders. If that checks out I am going to pull the heads and have them flowed. I didn't spend money on heads to get beat by cam only cars, so if anyone has any ideas on what might be wrong let me know.

zims350

car has comp r's shimmed to give me 10-15 thousands preload and I dont think its a vavle float problem, but I could be wrong. Dyno graph looks smooth no big drops in the curve

Ben01C5

Can you post the graph?

SouthFL.02.SS

Sorry 'bout those numbers, somethin's definately not right.

foff667

iTrader: (2)

is that with an ls1 or ls6 intake?

slyws6

Do a leak down test to ensure you didn't damage anything else when you bent those valves, also how do other cars dyno on their dyno? It may be really conservative, even if it is it still seems a little low sorry to hear that man.

-Sly

gomer

iTrader: (13)

I really hope you have a LS6 intake. What about an underdrive pulley, ported TB, and a cutout. Those 4 things can add up to some serious hp on the dyno. Post up the graph too.

slyws6

Hey gomer how much do you think a ported tb will add on a full out h/c car?

-Sly

foff667

iTrader: (2)

i would think 5-10...but if you get lets say 8 from tb 8 from pulley and 15 from ls6 your talking 420-430 to the wheels which isnt all that bad IMO that is of course if he doesnt have those.

ChevyWeatherman

iTrader: (2)

I just had Speed Inc. install and tune this cam on stock heads. Mine also hunts for idle occasionally, but I expected that. This is a big cam, you can't expect it to run like a stocker. People say the Speed's dyno always reads a bit low...don't know how true it is though. Yes, you need LS6 intake, TB, Pulley, Cutout. Choking a motor down adds up, especially when running a larger cam. You may even be rendering your heads somehwat ineffective (when comparing to others who have the mods done) by not letting the rest of the system flow like it could. 390 RWHP is still bad *** if you ask me, but if you want more, you'll probably have to do more.

Beast96Z

iTrader: (21)

Personally I don't think the cam should hunt for idle like you guys are saying. If it was tuned properly, it should not search. I've had cams this size and mail order tunes that did no searching at all.?

foff667

iTrader: (2)

mine doesnt hunt for an idle...it idles steady at 900-950...once and a while it will surge for like a minuted and then go away for like 3 days lol yah its a big cam but with a decent tune is a kick *** cam.

zims350

Hey guys the car is stock other than the heads, cam, headers, and lid. I did think that the ls6 intake, pulley, and ported tb was going to make that much of a difference on rwhp, but I guess I could be wrong. I will do those mods and see what I get after that. Hey does anyone know of a good trans shop in the chicago area, just lost second gear and was contimplating on doing it myself but if the price is right I'll take it out and bring it somewhere. One more thing to 231/237 guys does your car have a slight bog off idle and sometimes shifting gears at low rpm?

zims350

Hey chevyweatherman that 412 is a cam only car right, and that was on speed inc dyno. Did you have speed inc do the install? It took them a week to get my car dynoed because it needed a coolant sensor.

Black02SS

iTrader: (36)

Hey guys, maybe my input might help here. Last year I had Speed Inc. do my dyno and tune on my car. At that point in time (Sept. 03), I put down 411/378 with H/C through 12 bolt. Fastforward to this year. Changed out cam to a FM11, Headers, exhaust, and added a pulley. Managed last Tues to put down 403/381. :scratches head: Someone please tell me how you can add mods, GET FASTER at the track, and lose HP? I changed my springs to see if that might have been the problem and will dyno it locally this week hopefully.

gomer

iTrader: (13)

ding ding ding!! We have the answer to our question The LS6 intake, ported TB, ASP pulley, and Cutout WILL put you over 425rwhp with some tuning.. probably even more. I think a ported TB is worth 8 to 10rwhp on a full on H/C car that has all the other supporting bolt ons. Just as an example I dyno'd my BONE STOCK 2001 WS6 saturday... I did two pulls stock and then added only a ported TB and did two more pulls. Averaged the first two pulls and then subtracted that number from the average of the second two pulls. On a stock 2001 the ported TB was worth 6rwhp and 8rwtq. I've done the same testing a while back for an ASP pulley and it was worth 8rwhp and about the same RWTQ on a stock car.

btw... the tuning on your car has to be off some, I had a mail order tune with that cam in my car and never had any idle surging problems or anything else like you are talking about.

v8maro

iTrader: (4)

LOL, you sound like me, doing it ***-backwards. I had a heads/cam car running with only a lid! LOL
Now I have lid, cutout, ls6 intake (coming) LT's, and the H/C
Next will be the TB and pulley
-Steve

foff667

iTrader: (2)

he aint the only one but i recognize this and am working on it

zims350

Thanks guys I guess I need to spend some money on those items and go back to the dyno to see what it does. I dont think the tuning is the best and want to get it retuned hopefully they don't try to nail me for 450 again. Thanks for your help guys.

cracker

iTrader: (1)

In my cam only application I gained 24 rwhp with a LS6 intake and a S2 TB.

Not only do you have a 98 car which most will agree, dyno the lowest stock, but you are missing bolt ons. Did you dyno with your previous setup? Most application swaps are realative, not peak.