11.5.1 CR + stock 346 =??
#1
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My question is to anyone who can help me is can I safely run a 11.5.1 compression on a 117, 000 mile stock bottom end with out problems?
This is what I currently have:
2000 TA A4 346ci(Stock bottom)
TSP 228r
7.4 PR
Pac 1218s
Few other bolt ons
To that set up I want add these heads/springs/PR's which I already have:
Absolute Speed stg 2.5 5.3 heads
The chamber size is 58 cc(milled.030), valve size (Manley Valves) 2.05, 1.57, Springs are Comp 977s with titanium retainers
7.350” Comp Cam chromemoly pushrods
Ls7 lifters
OEM GM gaskets(0.52)
Will I be ok with doing this to my car with a good tune?
This is what I currently have:
2000 TA A4 346ci(Stock bottom)
TSP 228r
7.4 PR
Pac 1218s
Few other bolt ons
To that set up I want add these heads/springs/PR's which I already have:
Absolute Speed stg 2.5 5.3 heads
The chamber size is 58 cc(milled.030), valve size (Manley Valves) 2.05, 1.57, Springs are Comp 977s with titanium retainers
7.350” Comp Cam chromemoly pushrods
Ls7 lifters
OEM GM gaskets(0.52)
Will I be ok with doing this to my car with a good tune?
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it all depends on the cam and the valve events, the dynamic compression is much more important than static in a cammed engine. I am not entirely sure what is recommended on an ls but on an lt 9.5:1 DCR is about all you can muster on pump gas. I ran a 12.2:1 static lt1 on 91 octane with no knock retard. The lt1 info isnt entirely relevant but it just goes to show that static compression is only part of the picture. In my newly acquired ls knowledge 11.5 static is not that high but without a DCR calculator and a cam card in front of me I can't say for certain that this combo will be ok but more than likely you will be fine. I know TSP sells there ls1 longblocks with 5.3 heads which have 59cc chambers and similar head gaskets and I doubt they would sell someone a potentially volatile setup. Hopefully someone more knowledgable than I will chime in.
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You could get the seats cut to raise the valves up alittle higher.....but that might not give you more than 1 or 2 cc's
You can flycut the pistons in the block too, that might be your best option.
Granted I'm running a big cam, but I'm sitting at 12.56:1 scr and 8.25:1 dcr full timing and 0 kr. From want ive been told you want to stay under 8.5-max9:1 dcr....other wise you will have a very hard time fighting knock
You can flycut the pistons in the block too, that might be your best option.
Granted I'm running a big cam, but I'm sitting at 12.56:1 scr and 8.25:1 dcr full timing and 0 kr. From want ive been told you want to stay under 8.5-max9:1 dcr....other wise you will have a very hard time fighting knock
#6
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You could get the seats cut to raise the valves up alittle higher.....but that might not give you more than 1 or 2 cc's
You can flycut the pistons in the block too, that might be your best option.
Granted I'm running a big cam, but I'm sitting at 12.56:1 scr and 8.25:1 dcr full timing and 0 kr. From want ive been told you want to stay under 8.5-max9:1 dcr....other wise you will have a very hard time fighting knock
You can flycut the pistons in the block too, that might be your best option.
Granted I'm running a big cam, but I'm sitting at 12.56:1 scr and 8.25:1 dcr full timing and 0 kr. From want ive been told you want to stay under 8.5-max9:1 dcr....other wise you will have a very hard time fighting knock
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What's the LSA and intake centerline of that 228R? That will depend alot on how much dynamic compression will be created with that cam. If the cam is on a wider LSA, you may be fine on 93 octane.
I'm about to do a h/c setup involving Mamofied AFR 205's and a 235/235 cam on LSL lobes on a 114LSA +1. The heads will be milled to 60cc and with a 0.040" gasket, static compression will be ~11.4:1. But with the wider LSA and very little advance ground in, dynamic compression will fall ~ 8.4:1. If I were to go with a 112LSA and more advance, that number would jump to the high 8's without changing duration.
I use the calculators on www.smokemup.com.
Jason
I'm about to do a h/c setup involving Mamofied AFR 205's and a 235/235 cam on LSL lobes on a 114LSA +1. The heads will be milled to 60cc and with a 0.040" gasket, static compression will be ~11.4:1. But with the wider LSA and very little advance ground in, dynamic compression will fall ~ 8.4:1. If I were to go with a 112LSA and more advance, that number would jump to the high 8's without changing duration.
I use the calculators on www.smokemup.com.
Jason
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#8
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What's the LSA and intake centerline of that 228R? That will depend alot on how much dynamic compression will be created with that cam. If the cam is on a wider LSA, you may be fine on 93 octane.
I'm about to do a h/c setup involving Mamofied AFR 205's and a 235/235 cam on LSL lobes on a 114LSA +1. The heads will be milled to 60cc and with a 0.040" gasket, static compression will be ~11.4:1. But with the wider LSA and very little advance ground in, dynamic compression will fall ~ 8.4:1. If I were to go with a 112LSA and more advance, that number would jump to the high 8's without changing duration.
I use the calculators on www.smokemup.com.
Jason
I'm about to do a h/c setup involving Mamofied AFR 205's and a 235/235 cam on LSL lobes on a 114LSA +1. The heads will be milled to 60cc and with a 0.040" gasket, static compression will be ~11.4:1. But with the wider LSA and very little advance ground in, dynamic compression will fall ~ 8.4:1. If I were to go with a 112LSA and more advance, that number would jump to the high 8's without changing duration.
I use the calculators on www.smokemup.com.
Jason
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like nice pieces. 5.3 heads dont get milled a whole lot to get to 58cc but the
2.05 valves make it closer to the stock unaltered pistons soooo you're right
about staying 228 cam. Do you have decent 93 octane available in your area
I know some places only have 90-91.
#12
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@ A.R. Shale Targa Thanks and Yes all of our stations sell 92 and 93 Premium octane, thats all I have ever run
@ PREDATOR-Z thanks for the estimated DCR and SCR I was having trouble trying to put in the values. And as for measuring the PTV im gonna try the clay method to measure. If you have a better way please let me know Ill measure both ways.
@ PREDATOR-Z thanks for the estimated DCR and SCR I was having trouble trying to put in the values. And as for measuring the PTV im gonna try the clay method to measure. If you have a better way please let me know Ill measure both ways.
#17
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Absolute Speed stg 2.5 5.3 heads
The chamber size is 58 cc(milled.030)
The chamber size is 58 cc(milled.030)
I'll also add that single pattern cams (like a 228/228) typically like to trap more cylinder pressure. On a high compression application this isn't always a good thing. Sometimes the cranking compression will be so high (230+psi) that the car will violently detonate. If the heads are in fact a 706 casting shaved .030, I'd look into something like a 224/228 114LSA camshaft. It will provide enough bleed off, and still be a fun TQ'y setup. Cam Motion makes an excellent 224/228 camshaft I use all the time that is far superior to the Comp cam version.
One last thing, ditch the Comp 977's and get yourself a set of PSI 1511 Maxlife springs. You don't need a big heavy spring for an XE-R lobe, or most of Cam Motions lobes (what I use). PSI's also use the stock locking/retaining hardware, and have a zero percent failure rate.
OP, to answer your PM question concerning PR lengths. That setup has too many variables a few unknowns so I couldn't accurately give you an answer.
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Some interresting stuff in Damians post but I have point out something about the chamber size of 5.3 heads.Damian is forgetting that the chambers in ported 5.3 heads are not the stock 61 cc chambers.When the big intake vavles are put in the chambers are opened up around them.I think a lot of these heads are 63 cc unmilled-my ETP 5.3 heads are 64 cc unmilled.That is why .030 off would be 58cc.
#19
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Some interresting stuff in Damians post but I have point out something about the chamber size of 5.3 heads.Damian is forgetting that the chambers in ported 5.3 heads are not the stock 61 cc chambers.When the big intake vavles are put in the chambers are opened up around them.I think a lot of these heads are 63 cc unmilled-my ETP 5.3 heads are 64 cc unmilled.That is why .030 off would be 58cc.
A 2.05 intake valve on a stock 346ci engine is silly anyway.
#20
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The casting on these heads are 862 not 706. Which would put these heads at 63/64cc out the box. So since they are 58cc's theres no need to change the cam right? And as far as changing the springs I have the 977s(dual) and some pac 1218s (singles) that i am going with because I already have them on hand. So unless it takes away horsepower Im gonna run one of these sets, but thanks for the sugesstion.
So my question to you is should I sell these heads and buy another set? Or keep them and change the cam/keep the cam?
So my question to you is should I sell these heads and buy another set? Or keep them and change the cam/keep the cam?
Last edited by bernarlitt; 09-18-2011 at 09:39 PM.