LQ4 build needs your advice...

[killerinparadise]

I wanted to get some input from people on this site about a combo I'm thinking of putting together. It's a semi budget build because I'm not replacing anything in the bottom end apart from the rod bolts. I was originally going to do a turbo build with the low compression LQ4 block but other things have came up and I'm no longer able to follow this route. My goals for this combo are a reliable 450+ rwhp and mid-low 11's, let me know where you see anything that can be improved upon or changed and if my goals are realistic.

Basics:
'99 Z28
Pacesetter 1 3/4 longtube headers
Hooker Cat-back
Performabuilt 4L60E Tranny
3500 Stall
Stock 10 bolt

Engine Build:
Low mileage '04 LQ4
CNC'd L92 Cylinder heads milled to 65cc chambers (hoping to pump up the compression closer to 10:1)
LS7 Lifters
All ARP hardware Head/Rod/Crank bolt etc.
GM MLS head gaskets
ls6 oil pump
GMPP Carb style intake or Car Intake (still undecided on this)
Custom ground cam

Trying to keep the build somewhere around $4k. If you've got ideas on a cam profile to use let me know. I've already sold most of the turbo stuff I had and want to get started on this soon, spring is here and my car is still sitting in the garage not running

[Soul TKR]

Originally Posted by killerinparadise

I wanted to get some input from people on this site about a combo I'm thinking of putting together. It's a semi budget build because I'm not replacing anything in the bottom end apart from the rod bolts. I was originally going to do a turbo build with the low compression LQ4 block but other things have came up and I'm no longer able to follow this route. My goals for this combo are a reliable 450+ rwhp and mid-low 11's, let me know where you see anything that can be improved upon or changed and if my goals are realistic.

Basics:
'99 Z28
Pacesetter 1 3/4 longtube headers
Hooker Cat-back
Performabuilt 4L60E Tranny
3500 Stall
Stock 10 bolt

Engine Build:
Low mileage '04 LQ4
CNC'd L92 Cylinder heads milled to 65cc chambers (hoping to pump up the compression closer to 10:1)
LS7 Lifters
All ARP hardware Head/Rod/Crank bolt etc.
GM MLS head gaskets
ls6 oil pump
GMPP Carb style intake or Car Intake (still undecided on this)
Custom ground cam

Trying to keep the build somewhere around $4k. If you've got ideas on a cam profile to use let me know. I've already sold most of the turbo stuff I had and want to get started on this soon, spring is here and my car is still sitting in the garage not running

why don't you mill the heads to 59cc instead of 65cc??? up that compression...

look at my build

[djsanchez2]

What head gasket did you use Soul?

I'm using 5.3 heads and a .40 gasket for 10.9:1 on mine, also using a slightly larger cam too. I'm shooting for 450hp to the wheels, but it will be carbed so it should make things a lil easier. 224/236 .612/.609 117+2

For the OP- the cam specs will differ depending on the intake used. The lift on the L92 heads will also be lower for clearance reasons because of the large valves.

[sroach20]

make sure you prepare for the passenger side valve cover. your stock one will not clear without grinding the baffles because of the offset rockers. if you go car intake make sure you get the right extensions and plugs. the l76 you need to extend the map, ls3 you need an ls3 map and you need to extend/wire the new pigtail.

[sroach20]

Originally Posted by Soul TKR

why don't you mill the heads to 59cc instead of 65cc??? up that compression...

look at my build

he would need to change the pistons to mill those heads to 59cc. i took .030 off and my ptv was right a close to the limit.

[djsanchez2]

Not if you use 5.3 heads that come with a 59cc chamber Also depending on how bad the interference, he MIGHT be able to get away w/ a simple flycut.

[sroach20]

Originally Posted by djsanchez2

Not if you use 5.3 heads that come with a 59cc chamber Also depending on how bad the interference, he MIGHT be able to get away w/ a simple flycut.

but the 5.3s dont come close to the flow of some l92s.

[djsanchez2]

Hell no they don't but they can be ported to flow ~300cfm if valve size is increased. Just don't see the point of using heads that huge on a stock bottomend if they come with compromises and restrictions.

Can mill them too much, Can go big boy cam, hard to get good compression numbers (11+) for a solid combo, thus can't really tap into the huge flow numbers anyways.

[sroach20]

Originally Posted by djsanchez2

Hell no they don't but they can be ported to flow ~300cfm if valve size is increased. Just don't see the point of using heads that huge on a stock bottomend if they come with compromises and restrictions.

Can mill them too much, Can go big boy cam, hard to get good compression numbers (11+) for a solid combo, thus can't really tap into the huge flow numbers anyways.

they dont need a big cam to run, just the right cam. ive got a stock bottom lq4 and the l92s made it wake the hell up. its night and day difference between these and the 317s.

[djsanchez2]

Hmmm cuz i was on the fence between the two and had a cam spec'd for both set-up and got these two stealth cams

Carbed LQ4, TH400, 9", 2800lb Nova wagon

P&P 5.3 heads w/ ls1 intake valves: 224/236 .612"/.609" 117+2
out of the box L92's: 218/230 .595”/.600” 116+3

[sroach20]

i havent even had a chance to really tune it (work and school). i cant wait to see how it does when i get everything dialed in.

[Soul TKR]

Originally Posted by djsanchez2

What head gasket did you use Soul?

Just the regular 6.0 LS2 Head Gasket... don't remember the actual specs on thickness...

Originally Posted by sroach20

he would need to change the pistons to mill those heads to 59cc. i took .030 off and my ptv was right a close to the limit.

Really? I didn't have to change mine... the dished pistons that come in the LQ4 should give him enough clearance... course he didn't mention his cam specs, and i'm not that knowledgeable about the heads he's using so I don't know if that would make a difference compared to my setup...

[sroach20]

Originally Posted by Soul TKR

Just the regular 6.0 LS2 Head Gasket... don't remember the actual specs on thickness...



Really? I didn't have to change mine... the dished pistons that come in the LQ4 should give him enough clearance... course he didn't mention his cam specs, and i'm not that knowledgeable about the heads he's using so I don't know if that would make a difference compared to my setup...

the exhaust had allot of clearance, but the gigantic intake valves on the l92s are what cut it close.

[djsanchez2]

^^^

FYI the stock gasket is .051" thick and the dish on the piston is -6cc

And going off ur specs you should have a 10.8:1 compression Soul, not 11:1

[Soul TKR]

Originally Posted by djsanchez2

^^^

FYI the stock gasket is .051" thick and the dish on the piston is -6cc

And going off ur specs you should have a 10.8:1 compression Soul, not 11:1

eh... it's what my builder told me... maybe i can get him to chime in. I'm really not knowledgeable in the whole compression reading thing to know

just being honest...

[Ryne @ CMS]

Originally Posted by Soul TKR

eh... it's what my builder told me... maybe i can get him to chime in. I'm really not knowledgeable in the whole compression reading thing to know

just being honest...

with a 59cc chamber, 4" bore, .051" gasket w/ 4.065" bore, -6cc dish, plus with the pistons on his motor being .008" out of the hole i got his compression at 11.05:1

[Soul TKR]

Thanks Ryne

[djsanchez2]

I got everything else right though, dish cc, piston outta the whole, etc. Not questioning ur math, i'm just looking to make the same compression on my motor.

Oh i see, looks like the L92 gasket has a 4.065 bore. Did that replace the ls2 gasket?

[killerinparadise]

Originally Posted by Soul TKR

why don't you mill the heads to 59cc instead of 65cc??? up that compression...

look at my build

I want to use the l92 heads because of their great flow numbers and plan to eventually use these heads on a 402/408 setup. I figured with a 65cc chamber they would still work well on my stock LQ4 and I'd be able to run flat tops and make around 11:1 on a 408 setup in the future without having to have the heads redone and worry about even worse ptv issues.

Originally Posted by sroach20

make sure you prepare for the passenger side valve cover. your stock one will not clear without grinding the baffles because of the offset rockers. if you go car intake make sure you get the right extensions and plugs. the l76 you need to extend the map, ls3 you need an ls3 map and you need to extend/wire the new pigtail.

Thanks for the advice, so the stock valve covers can be made to work with the l92 heads? Or would it be easier to switch to a different style valve cover? Also what intake did you end up going with? I haven't looked to much into them. I'm thinking that the ls3 intake will be the best performing and easiest to swap and make fit under the hood but I'm not apposed to the GMPP Carb style intake.

Originally Posted by sroach20

he would need to change the pistons to mill those heads to 59cc. i took .030 off and my ptv was right a close to the limit.

I want to use the stock bottom end right now without having to flycut or pull out the pistons.

Originally Posted by sroach20

they dont need a big cam to run, just the right cam. ive got a stock bottom lq4 and the l92s made it wake the hell up. its night and day difference between these and the 317s.

Glad to hear that, were your 317's milled and ported? How about your L92's, did you get them cnc'd or are they stock milled?

Originally Posted by Soul TKR

Just the regular 6.0 LS2 Head Gasket... don't remember the actual specs on thickness...



Really? I didn't have to change mine... the dished pistons that come in the LQ4 should give him enough clearance... course he didn't mention his cam specs, and i'm not that knowledgeable about the heads he's using so I don't know if that would make a difference compared to my setup...

I know the Intake valve on the L92's are pretty massive and are what would cause ptv issues first. I'll be getting my cam spec'd to fit safely without having to flycut the pistons.

[djsanchez2]

I figured out what i was doing wrong on the calculator, i was putting the deck height as a positive number instead of a negative number DUH!! It comes out at 11.05:1 every time now.