bernarlitt

iTrader: (11)

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?

A.R. Shale Targa

iTrader: (2)

That much compression may become timing/octane sensitive w/228 cam
M6 or stalled A4 ????....I'd try the EPS 236 @.050 cam with your combo
if you can afford it.

JB_97ws6TA

iTrader: (6)

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.

bernarlitt

iTrader: (11)

Its a stalled A4 and Im kinda trying to avoid flycutting thats why im trying to stick with the 228r. So are you saying dont use the heads?

mark21742

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

bernarlitt

iTrader: (11)

Ok so I need to caculate the DCR? Gotcha! and Can the flycut be made with the motor in the car?

Camaro99SS

iTrader: (4)

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

bernarlitt

iTrader: (11)

Hey thanks for all the replies so far!! The LSA on my 228r is 112+2

bernarlitt

iTrader: (11)

Anymore thoughts about my setup? Anyone? I just want honest and straight to the point opinions!

Thanks in advance

A.R. Shale Targa

iTrader: (2)

Actually I'm trying to find a way for you to use them heads since they seem
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.

PREDATOR-Z

You'll have to measure PTV with those valves.
I got 8.93 DCR and 11.60 SCR
Bottom line Measure PTVc and if OK it will work on Premium Octane.

bernarlitt

iTrader: (11)

@ 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.

LS1axle

iTrader: (12)

When are you planning the install because im in the same boat?

bernarlitt

iTrader: (11)

Lol yeah that's right LS1axle let me be the guinea pig! But to answer your question, I'm calling TSP Monday morning and ordering some lifters, arp bolts, and head gaskets. And as soon as I get that package I'm gonna start turning some wrenches!

LS1axle

iTrader: (12)

Haha well if we gotta fly cut im goin with a bigger cam!

bernarlitt

iTrader: (11)

If I find out i have to fly cut I may getting a bigger one also! From reading other post and research fly cutting doesn't seem that bad, I just want to avoid it if I can.

Damian

iTrader: (89)

That doesn't add up. 5.3/706 castings are 61cc out of the box. Every .006 shaved is 1cc, so .030 off would make that 56cc. If that is the case, I'd check piston/valve clearance if the valves were not sunk in at all. Of course there's no way of knowing that now since Absolute is shut down.

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.

oldguy99Z

iTrader: (2)

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.

Damian

iTrader: (89)

I never paid much attention to Absolute stuff, that's why I said in my previous post that there's too many unknown variables.

A 2.05 intake valve on a stock 346ci engine is silly anyway.

bernarlitt

iTrader: (11)

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?