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Cam for L92 Heads: Lessons Learned

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Old 01-16-2010, 06:22 PM
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Originally Posted by gnfan
Don't have my notes in front of me, but if memory serves correct, Around .070 on the intake and the exhaust was a non issue. I have over a year of driving on the car with no problems. It's a DD car.
with the heads milled and thin gaskets?

Chad
Old 01-16-2010, 06:36 PM
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That is correct. 05 Ls2 GTO LS3 heads milled .030 .040 cometics about 12000 miles since the swap
Old 01-16-2010, 06:59 PM
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Originally Posted by gnfan
That is correct. 05 Ls2 GTO LS3 heads milled .030 .040 cometics about 12000 miles since the swap
hmm interesting, I'll measure the PTV here in a few days and let ya know.

I should have even more clearance with the lq4 dished pistons if that is the case.

how do you like that cam and what kind of power did you put down?

Chad
Old 01-16-2010, 07:29 PM
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I have not dynoed yet. I may go to Roswell NM its about 185 miles from me.
I have a few more cams I will try.
Old 01-16-2010, 07:36 PM
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Originally Posted by gnfan
I have not dynoed yet. I may go to Roswell NM its about 185 miles from me.
I have a few more cams I will try.
I heard they get some out of this world numbers there.

Jon
Old 01-16-2010, 08:30 PM
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Originally Posted by old sstroker
i heard they get some out of this world numbers there.

jon

lmao:d
Old 01-16-2010, 09:55 PM
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Originally Posted by gnfan
I have not dynoed yet. I may go to Roswell NM its about 185 miles from me.
I have a few more cams I will try.
so do you like it or ran the car with it?

Chad
Old 01-16-2010, 10:06 PM
  #188  
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Ya so far it runs good, a 3600 stall would be a tad better than my 2800 stall. I have a custom Brett Bauer cam That I want to try soon. But I want to get this dynoed first. And as far as drivability goes its very good,and I have the Idle at 830RPM.
Old 01-21-2010, 01:52 PM
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Default No dyno but track numbers.......

Ran two different cams in my G8 tuned by myself. Both cams worked with the DoD lifters with AFM still functional using 1.85 SLP rocker. First cam...

Lunati 217/225 .323/.318" lobe lift 114+4LSA Ran 12.37 @115

Second Cam....
Comp Thumpr 219/233 .326/.316 109+6LSA http://www.compcams.com/Cam_Specs/Ca...csid=1440&sb=0
Ran 12.20@115

Both ran with the DA @200FT. Aside from tuning the choppy idle, it runs good with the stock converter locked-up down to 1200rpm. Also the MAF graph at WOT throttle using the COMP was very smooth compared to the Lunati which was opposite of what I expected. Also the MAF average numbers were higher from 2800-6400 using the Comp. You would think the Comp cam would run slower but the track doesn't lie. Wonder how it would run installed straight up???
Old 01-21-2010, 02:34 PM
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The MPH is the barometer for horsepower, not ET, a better 60 ft could have changed your ET by that much very easily. It still takes X amount of horsepower to move XXXX amount of mass 1320 ft. If your MPH stays the same the horsepower didn't seem to change much if at all.

Last edited by 69LT1Bird; 01-21-2010 at 08:14 PM.
Old 01-21-2010, 07:49 PM
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Originally Posted by G8-4-speed
Ran two different cams in my G8 tuned by myself. Both cams worked with the DoD lifters with AFM still functional using 1.85 SLP rocker. First cam...

Lunati 217/225 .323/.318" lobe lift 114+4LSA Ran 12.37 @115

Second Cam....
Comp Thumpr 219/233 .326/.316 109+6LSA http://www.compcams.com/Cam_Specs/Ca...csid=1440&sb=0
Ran 12.20@115

Both ran with the DA @200FT. Aside from tuning the choppy idle, it runs good with the stock converter locked-up down to 1200rpm. Also the MAF graph at WOT throttle using the COMP was very smooth compared to the Lunati which was opposite of what I expected. Also the MAF average numbers were higher from 2800-6400 using the Comp. You would think the Comp cam would run slower but the track doesn't lie. Wonder how it would run installed straight up???
There you go 2 different cams tight vs wide lsa and almost identical result in Good comparison there.

cheers
Old 01-21-2010, 09:13 PM
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Originally Posted by 69LT1Bird
The MPH is the barometer for horsepower, not ET, a better 60 ft could have changed your ET by that much very easily. It still takes X amount of horsepower to move XXXX amount of mass 1320 ft. If your MPH stays the same the horsepower didn't seem to change much if at all.
Been 1.93 60ft with both cams. Sure, the horsepower is the same but the tighter LSA cam accelerated the motor a little faster after the shifts. It is a 4000+lb car w/driver, takes more than HP to move a car with a stock converter. With a higher stall converter, the cams 1/4 mile et difference would have been less or next to nothing with traction.

My point wasn't about horsepower, since they are almost identical, as much as the LSA comparison in relation to the cars et. Everything was next to identical except for cams. Both were tuned to the 12.6-12.7 on my WB, timing left the same, same stock A/S radials, same 60ft, same MPH, DA was within a 100ft of each other. As different as they seem, they ran the same.

I was just surprised that the 109+6LSA cam ran as well as it did, most people look at the Thumpr cam as a second-rate cam for guys that look for 'image" over power. The was a few reason for the cam change. One was for a less aggressive lobe to use with 1.85 rockers that still had the lift I was looking for to work with DoD lifters and give me good lift at the valve. Second was the tighter LSA to shift the power band down. It doesn't take much cam with the L92's to push the power past 6500. Don't feel like running the heavy valves and DoD lifters that hard. Not wanting a small cam and avoiding rpm got me to try the Thumpr, so far its a tuff cam and head-turner.
Wouldn't mind a little different LSA and advance but I like the lobe profiles for what there being used for.
Old 02-14-2010, 01:23 AM
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Originally Posted by G8-4-speed
Been 1.93 60ft with both cams. Sure, the horsepower is the same but the tighter LSA cam accelerated the motor a little faster after the shifts. It is a 4000+lb car w/driver, takes more than HP to move a car with a stock converter. With a higher stall converter, the cams 1/4 mile et difference would have been less or next to nothing with traction.

My point wasn't about horsepower, since they are almost identical, as much as the LSA comparison in relation to the cars et. Everything was next to identical except for cams. Both were tuned to the 12.6-12.7 on my WB, timing left the same, same stock A/S radials, same 60ft, same MPH, DA was within a 100ft of each other. As different as they seem, they ran the same.

I was just surprised that the 109+6LSA cam ran as well as it did, most people look at the Thumpr cam as a second-rate cam for guys that look for 'image" over power. The was a few reason for the cam change. One was for a less aggressive lobe to use with 1.85 rockers that still had the lift I was looking for to work with DoD lifters and give me good lift at the valve. Second was the tighter LSA to shift the power band down. It doesn't take much cam with the L92's to push the power past 6500. Don't feel like running the heavy valves and DoD lifters that hard. Not wanting a small cam and avoiding rpm got me to try the Thumpr, so far its a tuff cam and head-turner.
Wouldn't mind a little different LSA and advance but I like the lobe profiles for what there being used for.
Nice work your peak hp was similiar, but dynamic compression increased from the tighter lsa and crazy 103ICL. So much for tight lsa's not working and early ICL. Your IVC is approx 32 degrees@50 thou lift, this is very low, 4 deg in advance gives around 10 psi cranking comp, but since its a soft lobe without knowing the seat to seat duration I would say its on the higher side then that of a LSR lobe on same duration so this plays effect. It appears your avg torque has increased by possibly 20 footpound from the cam specs and increase in dynamic compression, this helps it everywhere and obviously improved the et. So all in all cams just put the power where you want it. wider lsa cams keep overlap down and help for a smoother running daily that will still make great hp, but if your tuner goes alright stick with the tight lsa cam in heavy car. I think it also to be careful with lobe selection, some guys have had much success with the fast ramp lobes, most get best results still with xer lobes on L92s they have proven results and easier on the gear then xfi. The LSR I like but I havent seen any crazy mph results with it in G8s. I am more inclined in running slightly less lift and softer lobe, since the intake valve is so big and heavy this is important. Even for a big revving motor this is even more important. So it appears the thumper is a good choice. Fast ramps do work in some setups but the local guys here still stick with the lower lift stuff and have record times.

One thing I have noticed of late by accident is the wide split cams ie 10 deg with some overlap on board appear to help the dip in tq between 3000 and 4000rpm with these heads on 6L. ie a 232 234 112+0 will have a slight dip in the tq curve a 232 240 even though this has more overlap the longer duration on ex side removes the dip in the curve and picks up a few hp up top, obviously the ex is scavenging better and there is more efficient cyl fill from the increase in overlap effect, so no loss in bottom end performance at all.

Last edited by hymey; 02-14-2010 at 01:38 AM.
Old 02-14-2010, 03:11 PM
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gotta admit i've read this post 2x and i'm still fuzzy on cam choices seems everyone has a different opion.... i've asked a few ppl and they all give me different anwsers! lol...... i'm doing the lq4/ls3 heads milled, with carb intake...car is a driver(6 speed/410's) and i want to see 550 fwhp .....
Old 02-17-2010, 10:33 PM
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Cool

Good thread. It's somewhat reinforced my thinking that I should be just fine with a "smallish" 224/232-type cam (although the VVT throws a little bit of a wrench into the works)...

Thanks for all the good info guys!
Old 02-18-2010, 05:25 AM
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i am unsure on were i stand with small or big cams for these heads... i got pat g to spec me out a cam for my 402 with cnc prc ls3 heads fast 102 and nick william 102 TB 4l65 4000 convertor 3.9's and car makes 460 rwhp.

ran it at the track and got a best of 11.4, i am upset as i had a standard 6.0 with a smaller cam same convertor and diff gears dual 3" exhaust etc and ran 11.2

Just so everyone knows the cam that was specced for me was a 239 251 @ 114+4 623 623 lsl lobe.

now im thinking its time to go a bigger cam and get into the tens??
Old 02-18-2010, 05:53 AM
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Originally Posted by Rocksteady
i am unsure on were i stand with small or big cams for these heads... i got pat g to spec me out a cam for my 402 with cnc prc ls3 heads fast 102 and nick william 102 TB 4l65 4000 convertor 3.9's and car makes 460 rwhp.

ran it at the track and got a best of 11.4, i am upset as i had a standard 6.0 with a smaller cam same convertor and diff gears dual 3" exhaust etc and ran 11.2

Just so everyone knows the cam that was specced for me was a 239 251 @ 114+4 623 623 lsl lobe.

now im thinking its time to go a bigger cam and get into the tens??
interesting...what was your trap speed/weight? seems off for sure that's a big split mine is a 227/235 .614/.621 113+4 LSL lobes its not yet in the car but I planned on going low 11's with it in an lq4

are you blowing thru the converter?

Chad
Old 02-18-2010, 11:38 PM
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Im doing a lq4 with ls3 heads and intake and was wondering how one of these two cams would work?
231/234 .643"/.598" 111 LSA
232/234 .595/.598 112 lsa

I have used the first cam in a ls1 and loved it. Just wondering how it would work with the low compression lq4 with ls3 heads.
Old 02-19-2010, 02:41 AM
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I checked my PTV clearance with this cam 227/239 .614/.624 115+3 with it having no issues...It's in a LS2 and the pistons are .008 out of the hole...I used stock LS3 gaskets and unmilled heads....I was wondering if anyone else had used a similar cam with no flycutting and there experience with it...thanks
Old 02-19-2010, 06:39 AM
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Originally Posted by bigfatls6
Im doing a lq4 with ls3 heads and intake and was wondering how one of these two cams would work?
231/234 .643"/.598" 111 LSA
232/234 .595/.598 112 lsa

I have used the first cam in a ls1 and loved it. Just wondering how it would work with the low compression lq4 with ls3 heads.
doing the same build myself, but am milling the heads and using a carb intake...still up in the air on the cam....leaning towards
comp part # 54-428-11 this one made 551 fwhp in a test....


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