Advice or Opinions on my iron ls2 build
04-16-2009, 04:37 PM
#1
Advice or Opinions on my iron ls2 build The motor Im building right now is out of the S-10 project my brother just sold. It is a lq9 that I modeled after the car craft 480hp article with the 6.0 lq9 and GMPP hot cam. I know the setup is a little on the mild side but it was for my little brother and I wanted to play it safe since it was in an s-10 with a t-56 and 3.73 gears. Im livening the combo up a little before I stab it in my 3300lb regal with 3.73 gears. Also the t-56 will be coming along for the ride. I slapped some new cam bearings in and changed one main (scratched during factory assembly) and had the crank polished to provide a solid foundation. The motor only has about 30k but better safe than sorry. I also got to correct some ring phasing issues while everything was apart. Four of the pistons actually had the top two piston rings phased within 10* of each other. I kinda wish I had compression tested it to see what the comp #'s were with the rings like that. Heres what is planned for the mods nothing crazy but I'd like something that has a more defined powerband than the hot cam so the stick will be a little more fun. I have most of the parts unless noted so if you think I could do better with something else let me know. BTW this motor was carbed before and will stay that way. Dont hate me!
Stock bottom end lq9 freshened
Unmolested 243 or 799 heads with patriot duals (dont have yet)
Ported and shimmed ls6 oil pump
Rollmaster double roller timing chain
GMPP single plane with custom 700 cfm dp holley (bad bitch)
Pacesetter 1.75" lt's modded for g-body chassis
Truck coils
Plugs (have ngk tr55 but not sure if I should change)
Ls2 flywheel with ls7 clutch (flywheel is ****** heavy might swap opinions?)
Cam f-12 or f-13 on a 112 (havent purchased yet)
Bottom line here is I want a torquey motor with a somewhat defined powerband that pulls to around 6000-6300 rpm. I figure if the hot cam got the motor to 480hp then the added point of compression from the 243's should net about 7-10% hp increase when combined with the better quench and efficiency of the 243 combustion chamber. Couple that with a bigger cam and I figure I should be good for about 520-530 fwhp. Opinions are welcome. One thing I'm concerned with is how much difference I will see from the cam change. I liked the hot cam but it felt like the motor was being held back by its low lift and wide pattern split. Im trying to go big enough to notice the change but not so big that I have to wait for power. That is about as simple as I can put it. Thanks for reading my novel guys I just want to give all the facts instead of the typical "what cam is best for my ls1 I want 800rwhp and 25mpg in the city" request. I'll post some pics later for you visual guys.
Stock bottom end lq9 freshened
Unmolested 243 or 799 heads with patriot duals (dont have yet)
Ported and shimmed ls6 oil pump
Rollmaster double roller timing chain
GMPP single plane with custom 700 cfm dp holley (bad bitch)
Pacesetter 1.75" lt's modded for g-body chassis
Truck coils
Plugs (have ngk tr55 but not sure if I should change)
Ls2 flywheel with ls7 clutch (flywheel is ****** heavy might swap opinions?)
Cam f-12 or f-13 on a 112 (havent purchased yet)
Bottom line here is I want a torquey motor with a somewhat defined powerband that pulls to around 6000-6300 rpm. I figure if the hot cam got the motor to 480hp then the added point of compression from the 243's should net about 7-10% hp increase when combined with the better quench and efficiency of the 243 combustion chamber. Couple that with a bigger cam and I figure I should be good for about 520-530 fwhp. Opinions are welcome. One thing I'm concerned with is how much difference I will see from the cam change. I liked the hot cam but it felt like the motor was being held back by its low lift and wide pattern split. Im trying to go big enough to notice the change but not so big that I have to wait for power. That is about as simple as I can put it. Thanks for reading my novel guys I just want to give all the facts instead of the typical "what cam is best for my ls1 I want 800rwhp and 25mpg in the city" request. I'll post some pics later for you visual guys.
04-16-2009, 06:30 PM
#2
Im not sure of the F12 specs, but ive seen good #'s with the F13 camshaft and should run very well in your combination. The 243 heads are pretty damn good, but whats the compression going to be with them? Stock truck heads are 71cc's and the LS6's are 64.5cc's stock. You should really try to get the compression around 11:1, with the aluminum heads it will be fine on 93 with even a decent tune up.
Are you going to race the car or is it a cruiser? If its in the budget, you could put in some 4.10 gears and go even a little hotter on the camshaft (like a F14) and still be very driveable with the T56.
Just throwing that out there. Good luck and sounds like a sweet combo.
Are you going to race the car or is it a cruiser? If its in the budget, you could put in some 4.10 gears and go even a little hotter on the camshaft (like a F14) and still be very driveable with the T56.
Just throwing that out there. Good luck and sounds like a sweet combo.
04-17-2009, 09:43 AM
#3
The compression should be 11.1:1 just like the ls2. I will also be sticking with the 3.73 gears because the cruise rpm's and gearing are about perfect for the car imo maybe 3.90's but that is the highest I'm willing to go. I had heard some people say that the f-14 is somewhat doggy below 3500prm on a ls1 it should be somewhat different on the 6.0 though esp with the higher compression. Im really concerned about killing the bottom end power since 6.0's really seem to shine there.
04-17-2009, 11:58 AM
#6
How are you coming up with those camshaft specs? Dyno sim program? Or have you used that cam before? If so I'd be interested in seeing any results. As far as the compression thing I have read that a compression increase nets from 4-8% increase. I guess alot of it has to do with what engine it is and its efficiency. Given that ls engines are far more efficient than say a traditional sbc I would think that the hp and torque increases might be near the higher end of the spectrum. It would be interesting to see a back to back dyno with only a compression increase on an ls motor.
Trending Topics
04-27-2009, 12:37 PM
#8
Here is the cam that Alan at Futral spec'd. I didnt even realize that they did that. I was gonna order the f-14 but I asked some questions about my setup since it was carbed and the predator z specs above. So they had me fill out the form with all my info. I noticed the cam has a 6* traditional split similar to the one that predator z listed above with slightly tamer lift. Here are specs. Opinions are welcome as always.
228 234 .575 .598 110 + 4
228 234 .575 .598 110 + 4
04-27-2009, 01:15 PM
#10
TECH Senior Member
0.050
228/234
110>LSA
106>ICL
8>IVO
40>IVC
51>EVO
3>EVC
114>ECL
11* Overlap
Now for my cam:
0.050
230/236
111>LSA
109>ICL
6>IVO
44>IVC
51>EVO
5>EVC
113>ECL
11* Overlap
228/234
110>LSA
106>ICL
8>IVO
40>IVC
51>EVO
3>EVC
114>ECL
11* Overlap
Now for my cam:
0.050
230/236
111>LSA
109>ICL
6>IVO
44>IVC
51>EVO
5>EVC
113>ECL
11* Overlap
04-27-2009, 04:20 PM
#11
How will those differ characteristically? I've been reading the understanding valve events thread but if you could dumb it down for me a little I'd appreciate it. Like how either cam will make the motor behave differently. Also I know Alans cam would be on cammotion lobes and I assume from reading alot of your posts you would use a combination of xer and xfi lobes right? Also I see that both cams have a tight lsa and generous overlap which is because it is spec'd for a carbureted application
04-27-2009, 04:35 PM
#12
TECH Senior Member
The lobes I am using are a bit more agressive, cam will peak a bit later than Futral's, my cam is a bit more intake biased. It will draw a bigger charge in so theoreticaly it will make a bit more power accross in the rpms and use the single plane potential a bit more.
04-27-2009, 07:21 PM
#13
The lobes I am using are a bit more agressive, cam will peak a bit later than Futral's, my cam is a bit more intake biased. It will draw a bigger charge in so theoreticaly it will make a bit more power accross in the rpms and use the single plane potential a bit more.
Gotcha. Thanks for breaking it down for me. I told him I didnt want to spin it past 6500 max and preferred 6-6300 so I suppose that explains why his is biased a little lower.
05-11-2009, 01:04 PM
#19
I think I'm gonna go with the cam pred-z spec'd. I think I'd rather err a little on the bigger side since this is not by any means a daily driver and both cams seem to be relatively similar in lift and duration. I set up the form on the tsp website for the custom cam and I think it looks right given the info I have. I'll post a screenshot for yall to look at.