Quoted For Truth

 

Right on and while beating on it your doing it in style! I said it before and ill say it again its amazing how much talent is on these forms!

 

Thanks for the update, sounds like it was a blast!

 

Congrats! Where's the video!? What kind of timing were you at at 17lbs when it pushed coolant? Did you check out the plugs? What HG's and fasteners/TQ did you use again? 14 pages is alot to sift back through!

 

Ya know there is sime video that was floating around facebook. Ill see if I can find it. It seems to like 18 degrees timing and I haven't tried higher. But it always loses trap mph when I go down even 1 degree. Just screwed in new BR7EF plugs as the 2500 mile ones seemed to be the culprit with a misfire the night before track day when we were out testing things. The BR7 plugs might be a tad bit too cold as they have never got clean and happy with street cruising even though she knocks down 18 mph and the A/F is in perfect control.

That makes me think they are a bit too cold if they never self clean. A/F was an average 11.5 to 1 playing it pretty safe and the head studs are ultra cheap Pro Comps tightened to I believe 80??? ft lbs. What kind of torque are those studs good for anyways?

 

Heard of a few guys taking china studs up to 80 ftlbs. Several snap at the 70-80ftlb level too. Might be stretching past the yield point at 80, weakening the clamping force. The guys that were running 4's at 40+lbs of boost with the SBE 5.3 used china studs and torqued them to 70 w/ ARP lube. (they had a dry deck/head on methanol) Comp suggested 60 and said not to go above 65.

There's a stress/strength test floating around somewhere where they compared the OEM head bolt to the comp china stud to an ARP stud. The OEM bolt and the stud were almost identical tensile strength wise. I'd guess that means the OEM torque to angle specs would be about perfect on the china studs. No idea what that would amount to as a torque value.

I went to 70 with ARP lube on my china stud 5.3. Started spitting coolant when I bumped timing from 14* to 17*. Ran excellent, I picked up with every degree and the plugs looked great (e85). Guessing cyl press around peak torque is just too much for it. 2 track visits later it blow torched deck/head. Plugs still looked great, no signs of detonation I could see. IMO if it's spitting now, pull the head before it gets worse. I've tried re-torqueing them, yet to have an LS9 gasket LS combo magically seal back up after it starts puking.

I'd guess with a high winding engine like that you could drop the timing down to 14* or less at peak torque and ramp back up to where it likes it from 6k to redline. Could also pour on more boost past 6k to make up for power lost with less timing.

I sure wouldn't want a hotter plug, what cruise timing are you running? I've seen guys running as high as 45* at light load/cruise.

 

Excellent advice. I saw your thread with the torched head gasket. I am running around 45 degrees cruise and for the most part imitating the OEM Camaro timing in the mileage areas. I agree a retorque probably wouldn't do a thing at this point and I should bite the bullet and pull the heads. So what do you think of the LS9 gaskets? I question what 7 layer can possibly do but on that same note, GM spent millions researching things so I shouldn't question it.

I have an iron block so I don't have to worry about the firing ring location like your aluminum block did. I appreciate all the info man!

 

I guess im guilty of what a lot of people do. I know full well a N/A LS motor needs 2 degrees rocked out at peak torque yet as a turbo motor I have the timing flatlined at 18 degrees the whole way. LOL

 

I think the head/deck moves a lot more than people realize. The added layers allow the gasket to flex with the deck/head without breaking the seal. Spoke with Justin (skinnies) who has done back to back testing between the ls1/ls9 HG, also OEM bolts VS ARP studs. As well as a few other guys that have tried many different HG's on 600-900hp SBE LS builds. Felpros MLS, LS1/truck 3 layer MLS, cometic, etc... All of them had the best luck with the LS9 gasket. Once you get into big power with 1/2 studs and aftermarket blocks/heads I'm sure there are better options with o-rings and what not. For an SBE deal, I think it's pretty hard to beat the LS9.

Weren't you running pump gas? What RPM did it make peak torque?

 

50/50 race gas and 92 pump. Its so hard to tell the exact torque peak since boost is on the rise and the torque peak is always at the rpm where boost levels off around 5000-5200 rpm. The other thing I have come to realize when comparing the dyno to the track is I don't really know where the power peak is. The dyno says 7100 rpm but the track seems to prefer a much lower 6500-6700 rpm for the best times.

I know the converter aint the greatest and my theory is it burns thru the converter so bad at peak power that until power falls off and the converter catches up a bit (the power rolling off helps that happen), the dyno shows the peak in the wrong spot. Im posting 15% slip thru the top end and it seems to be getting worse as I go. My guess is the converter fins are laying over. The interesting side effect is my foot brake launches are getting better and better as its boosting to a much higher RPM. It needs WAY more stall than im willing to do in order to be a good foot brake car but street driving would be horrible. Nitrous seems to get me the best of both worlds though! LOL

Compared to the much lighter, more aerodynamic Trans Am, this Chevelle is a pig that wont trap the mph I think it should. The more fuel I take out the better it has gotten though. 11.4 to 1 is still pretty rich so next time out I think ill draw out some top end fuel to 12.0 and see what happens. Cant go fast without taking a few chances right?

- - - Updated - - -

Oh yeah and thank you for the info on LS9 gaskets I think that's exactly what I need!

 

Jesus hates a pussy.

 

Seems like pump/race gas is usually happier around 12. Give her a go and watch them plugs! Probably safe to say it’s past peak TQ by 6k? 12-14* from 5-6k and ramp back to 18* above maybe?

16psi leaving my nitrous on VS 19lbs and shutting it down. The nitrous pass netted a slower trap (147 VS 149) and indicated a hotter plug. Same timing and Auto tune dialed in the AFR to 11.3 on both runs (e85). With a BR7 plug I was seeing heat down into the 2nd thread leaving the nitrous on. No heat in the 2nd thread on 19psi run. N20 is awesome, but I like to shut that stuff off as soon as the boost can take over. Maybe I needed to richen up the mixture a lot more with the N20 or drop timing to see the better gains? Was also only running a 50ish dry shot. (hand drilled a jet, was supposed to be 50-60 shot range.)

That converter sounds like it’s toast. May look into the cheaper 10” PTC unit if you don’t want to spend a mint. ($450 vs the usual $1000 for their 9.5”) Ran it in a few buddies cars around 600-700hp they see roughly 6-8% and they aren’t revving it over 6700. Pretty good for a cheaper unit. I just picked one up for the new project. (3 week back order though!)

Good luck!

 

Great info thank you! That cheapo converter sounds pretty impressive especially for such good percentages of slip in the sub 7000 rpm range. Sounds like exactly what I need.

 

Just read thru this whole build, that car is bad ass!! keep us updated!

 

I agree.

I'd like a few images of the combo and the completed car.

 

Here is a recent photo I took of my 4 year old kid Timmy with my chevelle and the silver one he is going to get when he is older. LOL. So far I have 3700 miles on the car and its been the most reliable thing I have ever owned. And the LS gasketing technology makes for an engine that's never really dirty underhood. I wipe off the dust once in a while, check the oil level and go another 1000 miles without touching it. The next mod will be to rebuild and update my trusty 2004r transmission and get some overdrive and lockup to fine tune the car as a whole and get the best mileage it can.

So far its clicked off a 10.23 @ 131 mph without trying too hard or breaking anything. Not too bad!

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I may have missed it, but what rods are you using with the 4.8 crank and 6.0 pistons? Great looking car by the way!

 

Wow...very nice.

Again, this the same car in the Wrenchrat video?

 

Yes same car only totally rebuilt now.

 

Thanks for the compliment! Stock 4.8 rods and 6.0 pistons. The rods are longer to make up for the shorter stroke so after a minor rebalance its pretty much plug and play like GM themselves built it.