LQ4 - Budget Build with L92 Heads
10-07-2009, 11:14 AM
#1
Teching In
Thread Starter
Join Date: Nov 2007
Posts: 18
Likes: 0
Received 0 Likes
on
0 Posts
LQ4 - Budget Build with L92 Heads I just put a '03 LQ4 into my '98 Jeep Wrangler with a NV4500 trans and Atlas II 3:1 transfer case. The LQ4 is a stock Express 2500 6.0L with the 317 casting heads. Stock intake and is still drive by cable since it came from a van. It took a couple years of research to pick the best components for the build, but Phase 1 is now complete and on to Phase 2. Time to put some love into the LQ4.
From doing some light reading on the LQ4, I found that L92 heads are realatively inexpensive and will yield some nice gains. Trying to stick to a budget, if I go to the L92 heads what other components do I need to swap and what would be nice to swap at the same time? i.e Cam.. etc. Ultimately, I would like to get at least 400-500 HP, naturally asperated, and still be able to run pump gas. Anything beyond that is gravy. I would really like something that has been tried and true as opposed to trying to have a custom CAM or other components built.
Here is what I know so far:
1.) The 317 heads are Cathedral ports and the L92 are rectangular, so more than likely I'm going to need to change the Intake.
2.) The '03 LQ4 still runs a return on the fuel, where the LY6 (where the L92 heads are from) does not need a return.
3.) I would like to stick with EFI as opposed to carburator since this will be a rock krawler and won't be on flat surfaces regularly.
Trying to keep this build as inexpensive as possible, what components do I need to change?
1.) Higher pressure injectors? If so, new fuel pump or booster pump? Larger Fuel lines, currently running 3/8 supply with 5/16" return.
2.) New fuel rails?
3.) Intake?
4.) Larger throttle body?
5.) Cam.. etc..
Thanks in advance for everyones input..
From doing some light reading on the LQ4, I found that L92 heads are realatively inexpensive and will yield some nice gains. Trying to stick to a budget, if I go to the L92 heads what other components do I need to swap and what would be nice to swap at the same time? i.e Cam.. etc. Ultimately, I would like to get at least 400-500 HP, naturally asperated, and still be able to run pump gas. Anything beyond that is gravy. I would really like something that has been tried and true as opposed to trying to have a custom CAM or other components built.
Here is what I know so far:
1.) The 317 heads are Cathedral ports and the L92 are rectangular, so more than likely I'm going to need to change the Intake.
2.) The '03 LQ4 still runs a return on the fuel, where the LY6 (where the L92 heads are from) does not need a return.
3.) I would like to stick with EFI as opposed to carburator since this will be a rock krawler and won't be on flat surfaces regularly.
Trying to keep this build as inexpensive as possible, what components do I need to change?
1.) Higher pressure injectors? If so, new fuel pump or booster pump? Larger Fuel lines, currently running 3/8 supply with 5/16" return.
2.) New fuel rails?
3.) Intake?
4.) Larger throttle body?
5.) Cam.. etc..
Thanks in advance for everyones input..
10-07-2009, 11:32 AM
#2
I just put a '03 LQ4 into my '98 Jeep Wrangler with a NV4500 trans and Atlas II 3:1 transfer case. The LQ4 is a stock Express 2500 6.0L with the 317 casting heads. Stock intake and is still drive by cable since it came from a van. It took a couple years of research to pick the best components for the build, but Phase 1 is now complete and on to Phase 2. Time to put some love into the LQ4.
From doing some light reading on the LQ4, I found that L92 heads are realatively inexpensive and will yield some nice gains. Trying to stick to a budget, if I go to the L92 heads what other components do I need to swap and what would be nice to swap at the same time? i.e Cam.. etc. Ultimately, I would like to get at least 400-500 HP, naturally asperated, and still be able to run pump gas. Anything beyond that is gravy. I would really like something that has been tried and true as opposed to trying to have a custom CAM or other components built.
Here is what I know so far:
1.) The 317 heads are Cathedral ports and the L92 are rectangular, so more than likely I'm going to need to change the Intake.
Yes, will need l92 truck intake and 90mm cable drive throttle body
2.) The '03 LQ4 still runs a return on the fuel, where the LY6 (where the L92 heads are from) does not need a return.
return fuel works fine, the heads so not care. if anything return fuel is better than deadhead fpr. may be able to reuse the lq4 return fuel rail with injectors on l92 truck intake
3.) I would like to stick with EFI as opposed to carburator since this will be a rock krawler and won't be on flat surfaces regularly.
efi is the best option for this application.
Trying to keep this build as inexpensive as possible, what components do I need to change?
use as much oe parts as possible
1.) Higher pressure injectors? If so, new fuel pump or booster pump? Larger Fuel lines, currently running 3/8 supply with 5/16" return.
-if possible use at least 1/2in. or -8 for both return and supply
2.) New fuel rails?
-maybe able to reuse lq4 rail with l92 intake, but now is the time to step up to a aftemarket rail with aeromotive fpr.
3.) Intake?
-07+ l92 truck intake manifold
4.) Larger throttle body?
-90mm 4 bolt cable drive, Morris (see link) has one for less than 300$ new
5.) Cam.. etc..
-02-04 ls6 will work fine for what you are trying to build, or stick to the GM ASA or Hot cam. these will allow to use oe ls6,ls2 springs. if trying to stay on budget. will need to verify pushrod length and recommend the heads milled to raise SCR and thinner head gaskets to improve quench. shoot for at least 10:1. stock LQ4 is 9.4:1 with stock heads.
Thanks in advance for everyones input..
From doing some light reading on the LQ4, I found that L92 heads are realatively inexpensive and will yield some nice gains. Trying to stick to a budget, if I go to the L92 heads what other components do I need to swap and what would be nice to swap at the same time? i.e Cam.. etc. Ultimately, I would like to get at least 400-500 HP, naturally asperated, and still be able to run pump gas. Anything beyond that is gravy. I would really like something that has been tried and true as opposed to trying to have a custom CAM or other components built.
Here is what I know so far:
1.) The 317 heads are Cathedral ports and the L92 are rectangular, so more than likely I'm going to need to change the Intake.
Yes, will need l92 truck intake and 90mm cable drive throttle body
2.) The '03 LQ4 still runs a return on the fuel, where the LY6 (where the L92 heads are from) does not need a return.
return fuel works fine, the heads so not care. if anything return fuel is better than deadhead fpr. may be able to reuse the lq4 return fuel rail with injectors on l92 truck intake
3.) I would like to stick with EFI as opposed to carburator since this will be a rock krawler and won't be on flat surfaces regularly.
efi is the best option for this application.
Trying to keep this build as inexpensive as possible, what components do I need to change?
use as much oe parts as possible
1.) Higher pressure injectors? If so, new fuel pump or booster pump? Larger Fuel lines, currently running 3/8 supply with 5/16" return.
-if possible use at least 1/2in. or -8 for both return and supply
2.) New fuel rails?
-maybe able to reuse lq4 rail with l92 intake, but now is the time to step up to a aftemarket rail with aeromotive fpr.
3.) Intake?
-07+ l92 truck intake manifold
4.) Larger throttle body?
-90mm 4 bolt cable drive, Morris (see link) has one for less than 300$ new
5.) Cam.. etc..
-02-04 ls6 will work fine for what you are trying to build, or stick to the GM ASA or Hot cam. these will allow to use oe ls6,ls2 springs. if trying to stay on budget. will need to verify pushrod length and recommend the heads milled to raise SCR and thinner head gaskets to improve quench. shoot for at least 10:1. stock LQ4 is 9.4:1 with stock heads.
Thanks in advance for everyones input..
10-07-2009, 11:45 AM
#3
TECH Senior Member
The only thing is L92 have 71cc chambers and will not improve compression so you'll still have a low compression engine.
Bumping it to 10.5>11:1 will yield more power and get you closer to your goals.
If you mean 500 fwhp that is, 500 rwhp would be a tall order. I would not use LS6/LS2 springs with the L92 heavy intake valve and a ASA cam, PAC 1518 would be better.
IMO, going with 243 castings would yield better results with the right cam.
Bumping it to 10.5>11:1 will yield more power and get you closer to your goals.
If you mean 500 fwhp that is, 500 rwhp would be a tall order. I would not use LS6/LS2 springs with the L92 heavy intake valve and a ASA cam, PAC 1518 would be better.
IMO, going with 243 castings would yield better results with the right cam.
10-07-2009, 11:59 AM
#4
The only thing is L92 have 71cc chambers and will not improve compression so you'll still have a low compression engine.
Bumping it to 10.5>11:1 will yield more power and get you closer to your goals.
If you mean 500 fwhp that is, 500 rwhp would be a tall order. I would not use LS6/LS2 springs with the L92 heavy intake valve and a ASA cam, PAC 1518 would be better.
IMO, going with 243 castings would yield better results with the right cam.
Bumping it to 10.5>11:1 will yield more power and get you closer to your goals.
If you mean 500 fwhp that is, 500 rwhp would be a tall order. I would not use LS6/LS2 springs with the L92 heavy intake valve and a ASA cam, PAC 1518 would be better.
IMO, going with 243 castings would yield better results with the right cam.
10-07-2009, 12:15 PM
#5
Teching In
Thread Starter
Join Date: Nov 2007
Posts: 18
Likes: 0
Received 0 Likes
on
0 Posts
Yeah, just talked to the guys over at Texas S&P and they said they same thing. Some LS2/6 heads (243s) machined a bit and a CAM would easily get me to 500hp with mid 10s on compression. Not only that but I will be able to retain my current intake, injectors, TB, fuel rails, etc. So for right around 2k I'll get an additional 200hp. That's more than enough for right now. Hopefully I won't need more than 500hp in a Jeep.
Thanks for everyone's input.. If you have any more, keep it coming.
Thanks for everyone's input.. If you have any more, keep it coming.
10-07-2009, 01:40 PM
#6
11 Second Truck Club
iTrader: (5)
Join Date: Sep 2005
Location: Kansas
Posts: 1,331
Likes: 0
Received 0 Likes
on
0 Posts
If it was me I wouldn't try to make anywhere near that horse power with the stock L92 valves at all. I would go to Ferrea if I planned on spinning any RPM at all with a L92 casting. And trying to make 500 rear wheel horse at less then 7000 RPM with a cam that makes any low end torque at all (which is what I would want in a rock crawler) is going to be impossible. You need to re-evaluate your goals, 500hp is for dragsters spinning 7500 at the track, you want a cam that will make 500 ft/lbs at about 3500 rpm, if you wanna crawl. Call Texas Speed back and ask them at what RPM they think this combo will make 500hp and where will will start building useable torque.
Last edited by MPFD; 10-08-2009 at 01:45 PM.
10-07-2009, 02:09 PM
#7
TECH Enthusiast
iTrader: (6)
Join Date: Aug 2002
Location: Readsboro, VT
Posts: 529
Likes: 0
Received 0 Likes
on
0 Posts
The only thing is L92 have 71cc chambers and will not improve compression so you'll still have a low compression engine.
Bumping it to 10.5>11:1 will yield more power and get you closer to your goals.
If you mean 500 fwhp that is, 500 rwhp would be a tall order. I would not use LS6/LS2 springs with the L92 heavy intake valve and a ASA cam, PAC 1518 would be better.
IMO, going with 243 castings would yield better results with the right cam.
Bumping it to 10.5>11:1 will yield more power and get you closer to your goals.
If you mean 500 fwhp that is, 500 rwhp would be a tall order. I would not use LS6/LS2 springs with the L92 heavy intake valve and a ASA cam, PAC 1518 would be better.
IMO, going with 243 castings would yield better results with the right cam.
Trending Topics
10-07-2009, 02:17 PM
#8
TECH Senior Member
No LQ9 would benefit more from L92s. The LQ4 demise are the dish pistons for a ~9.4 SCR. While LQ9 and a slight mill will still allow a decent cam with decent compression.
10-08-2009, 09:47 AM
#9
Teching In
Thread Starter
Join Date: Nov 2007
Posts: 18
Likes: 0
Received 0 Likes
on
0 Posts
Called the guys at Texas S&P back and they said they have done this setup before.. Acording to them, they estimate that around 3000 RPM i'll be pushing 350ft lb of torque and will top out at about 6800 RPM at around 500ft lb.
Given the information I've shared, what would be an ideal setup for the LQ4 I already have. I don't mind discussing the information I've already gotten, as I'm not the source. But I would really like to hear other people oppinions of what I should do so I don't have to tear this thing aparts multiple times playing trial and error.
When it comes to heads, cam, engine internals, I'm certianly still a newbie.
Thanks Again for everyone's input.
Given the information I've shared, what would be an ideal setup for the LQ4 I already have. I don't mind discussing the information I've already gotten, as I'm not the source. But I would really like to hear other people oppinions of what I should do so I don't have to tear this thing aparts multiple times playing trial and error.
When it comes to heads, cam, engine internals, I'm certianly still a newbie.
Thanks Again for everyone's input.
10-08-2009, 01:11 PM
#10
11 Second Truck Club
iTrader: (5)
Join Date: Sep 2005
Location: Kansas
Posts: 1,331
Likes: 0
Received 0 Likes
on
0 Posts
Where are you crawling at? Most of my off road experiences have been in Colorado and I would think DA is gonna play big part in your final goal. I would stick with 317's, it will save you money all around. But don't set a "toke" HP goal before you even start the build. If you want more compression take your heads down to a machine shop and get em milled down a little. The LQ4's dish will be fine. Call Ed Curtis and have him grind you a cam for another $50 more then TSP is charging, that will be more suited to your rig. This is the kind of torque I'm talking about, and thats a 5.3!
http://www.youtube.com/watch?v=OBWEY...e=channel_page
http://www.hardcorels1.com/vbulletin...highlight=jeep
http://www.youtube.com/watch?v=OBWEY...e=channel_page
http://www.hardcorels1.com/vbulletin...highlight=jeep
Last edited by MPFD; 10-08-2009 at 01:47 PM.
