LM7 Sportside Z71

iTrader: (2)

putting an sts t67 kit on my 2000 ls1. looking at swapping cam and heavily considering/looking for a 02-04 ls6 cam for sale. I have 1 3/4 longtubes on there now and wondering how much ill really benefit with putting stock manifolds on there being that its a 6 speed car if im racing someone it wouldnt ever be below 4000 rpm other than a launch on the street...also considering and looking for a good set of 317's for sale??? then meth kit, ls2 intake, 90mm throttle body, 60 lb injectors, dual in tank fuel pumps...looking for any cam or other part suggestions looking to make 550-625rwhp ne suggestions would be greatly helpful! thanks, Tyler

knappbunch

get an intercooler. you can do stock manifolds or wrap the headers.

Schantin

iTrader: (6)

Stock manifolds will do better than LT's. It's due to heat retention/surface area. Ceramic coated headers aren't as bad (I ran them with the STS), but still worse than stock manifolds.

Lots of cam choices. Check with Patrick G for a spec. A lazy route is you could buy my old STS cam Still have the Comp 228/228 .588/.588 116LSA cam I used on the car w/ 317 heads. PM if interested. Even have the cam card.

Check posts by Zombie, LongRange4U (and myself if you get bored). Lots of STS info that can help ya' out.

elias_799

iTrader: (8)

defiantly get some lq9 heads (317's) to lower the CR. you can get them at a scrapper for about 230 bucks good luck

RooRnZ28

iTrader: (14)

get rid of the LT's... although they will work, the difference in power/spool/throttle response with the stock manifolds makes the switch well worth it.

LM7 Sportside Z71

iTrader: (2)

ic ic...now will switching from the lts to the manifolds hurt my peak power and how much quicker will it spool with the exhaust manifolds?? im mainly wondering if there is an overall power GAIN ill get from the manifolds and if so how much? i really dont want to wrap my headers or exhaust because ive heard that after a lil while by keeping all that heat in on that thin of metal it will rust right through everything. also ive heard that the meth kits are more efficient on sts kits?? is this true or do most run intercoolers?

LM7 Sportside Z71

iTrader: (2)

Hey man jw if you switched to the manifolds after your dyno because in an old thread that you posted when you had your car dynoed you had the LTs on your car? jw if you did cuz you should know better than neone what the difference would be....thanks, Tyler

Schantin

iTrader: (6)

The reason the stock cast manifolds are better is as said, they decrease turbo lag (increase spool...however you want to say it.) The faster you begin making boost, the faster you make power. End result, more power under the curve. Might not help the peak #'s....but it'll get the car down the pavement a lot faster.......which is the real point in the end.

You can run coated LT's...but you will get some lag. I had coated DynaTech LT's....but that's because my wife accidently gave away the stock manifolds at a garage sale I made full boost by 3500RPM in 1st, 3000RPM in 2nd, and 2500RPM in 3rd and above. It probably would have been 500RPM faster in every gear with the stock ones.

shawn_c992001

Would extrude honing the manifolds just to smooth things up, nothing crazy, help with spool?

LM7 Sportside Z71

iTrader: (2)

Ok yea i understand that but now you couldnt you decrease turbo lag in other ways...say with longtubes you run into the 3inch Ypipe and single 3 inch all the way back to the turbo and then go like 2 1/4-2 1/2 inch pipe which would be forcing that same amount of air from a big pipe into a smaller dimension pipe increasing heat and velocity to make the turbo spool quicker??? Because really the reason you would rather run stock manifolds is because the exhaust ports on the manifolds is smaller than the 1 3/4 in headers speeding up air flow as in almost a restriction? also i know the manifolds do hold the heat better but i would be making more heat by shoving that 3inch into a smaller pipe right before it spools the exhaust housing....what ya think about that? btw thankyou for all the input from everyone so far!!!

RooRnZ28

iTrader: (14)

yes, that is an old dyno graph from when i first put the kit on and it had the LT's.. the difference is well worth the switch. I can tell that the car runs much smoother/stronger, but it is also MUCH louder

Schantin

iTrader: (6)

Been there and tried that. What you're referring to is Bernoulli's principle that x volume of gas will have to accelerate to move through a smaller diameter tube. Doesn't work in this cse. My origonal setup was 2 1/2" Y-pipe stepped to a 2" I pipe into the turbo. Saw spool times increase to 3600-3800RPM. Went' 3" I pipe and they decreased to 3400RPM. Wrapped the exhaust from the Y-pipe back to retain heat and they dropped another 200RPM. I also maintained high-flow converters. Those create heat in their own right (and flow restriction to a degree...though I run Powerflo cats which are pretty free-flowing). The difference would have been greater w/out cats.

In short, heat retention is what you want. Long tube headers have too much surface area to maintain heat. Coating helps, but it's not as good as stock cast manifolds.