CR help...not a stupid question btw
Originally Posted by ddnspider
thanks...guess its 348@15psi should do the trick!
TECH Enthusiast
Joined: Jul 2004
Posts: 546
Likes: 1
From: Washington
wait a sec why aren't you getting the bigger cubed motor? Your dynamic compression ratio is what really matters. Get a reverse split cam or something with a longer duration that closes a bit later ABDC. That will bleed off some of the compression and you should do just fine. That pressure "bleed" is just going back into the intake manifold; it's not like blow-by on a narrow lobe separation angle cam.
Your engine builder doesn't know all this stuff???
Your engine builder doesn't know all this stuff???
TECH Enthusiast
Joined: Jul 2004
Posts: 546
Likes: 1
From: Washington
easily.
Suppose you had a static compression ratio of 9.5:1. Take a standard 224° cam that closes 66° ABDC. That would give you a dynamic compression ratio of 7.57:1 and on 15psi of boost, a 15.29:1 dynamic boost compression ratio, which is a little high.
Change to a 236° cam that closes 72° ABDC. your dynamic compression ratio drops to 7.21:1 and your dynamic boost compression ratio (with a 15psi charge) is down to 14.57:1.
To make it nice and easy to tune, I'd get something like a 238° / 224° on a 116° LSA with an intake centerline of at least 116°
Suppose you had a static compression ratio of 9.5:1. Take a standard 224° cam that closes 66° ABDC. That would give you a dynamic compression ratio of 7.57:1 and on 15psi of boost, a 15.29:1 dynamic boost compression ratio, which is a little high.
Change to a 236° cam that closes 72° ABDC. your dynamic compression ratio drops to 7.21:1 and your dynamic boost compression ratio (with a 15psi charge) is down to 14.57:1.
To make it nice and easy to tune, I'd get something like a 238° / 224° on a 116° LSA with an intake centerline of at least 116°
TECH Enthusiast
Joined: Jul 2004
Posts: 546
Likes: 1
From: Washington
this is for a turbo application, right? Turbos love reverse split cams.
And you don't have to grind a long duration intake cam to get this effect. Just moving the intake valve open event (thus the intake centerline) to a later angle and widening up the lobe separation will have the same effect.
like a 228 / 228 on a 118° LSA and 118° ICL
And you don't have to grind a long duration intake cam to get this effect. Just moving the intake valve open event (thus the intake centerline) to a later angle and widening up the lobe separation will have the same effect.
like a 228 / 228 on a 118° LSA and 118° ICL
Last edited by narcszm; Jun 8, 2005 at 10:10 AM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Originally Posted by narcszm
sounds like a stroker is too complicated for you and your engine builder. just build a 348.
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
I don't know what to say guys but one more time:
http://www.latemodelengine.com/
Give Bryan a call, he knows what a stroker is
http://www.latemodelengine.com/
Give Bryan a call, he knows what a stroker is
ive already paid half up front and the company stays in contact w me.the companies talked to him as well he's just waiting to hear back about giving them the half up front himself.no biggie.if LME was offering a better price we would have gone with them.
I still don't see why you can't go lower on your piston dish. Why does it have to be 9cc's? How come you can't get 15cc's or 30cc's if you wanted? It might cost you a few bucks more, but who cares if you can get more cubes? If it were me and I wanted to run 12-15psi, I would use:
3.905 bore
4.00" stroke
.040" head gaskets
-.003 deck height
15cc dished pistons
72cc combustion chambers
This nets 9:32:1 compression. You should be able to easily run the amount of boost you want with that. If you want lower compression, a 16cc will get you 9:1:1, and a 17cc will get you 9:0:1. Any piston company should have these pistons ready.
When it comes to cams, in a turbo/stroked application, you low-end power is going to be overwhelming. I would deffinatlly steer away from "hard lobes" like the XE-R's. There is no need in running a lobe that hard when the power is already there. Save yourself some work, money, and time and get something along the lines of a XE lobe. Personally, I'd call Futral and have them grind you one to your application. I'd say something around a 228/224 115LSA would work nicely and be very streetable.
3.905 bore
4.00" stroke
.040" head gaskets
-.003 deck height
15cc dished pistons
72cc combustion chambers
This nets 9:32:1 compression. You should be able to easily run the amount of boost you want with that. If you want lower compression, a 16cc will get you 9:1:1, and a 17cc will get you 9:0:1. Any piston company should have these pistons ready.
When it comes to cams, in a turbo/stroked application, you low-end power is going to be overwhelming. I would deffinatlly steer away from "hard lobes" like the XE-R's. There is no need in running a lobe that hard when the power is already there. Save yourself some work, money, and time and get something along the lines of a XE lobe. Personally, I'd call Futral and have them grind you one to your application. I'd say something around a 228/224 115LSA would work nicely and be very streetable.
Originally Posted by ddnspider
You're telling me! i need someone whose either done this or knows what their talking about to figure out how much boost we can SAFELY run with a 9.7:1 CR with the 383,then we'll know our next step.
i need someone whose either done this or knows what their talking about to figure out how much boost we can SAFELY run with a 9.7:1 CR with the 383,then we'll know our next step.But I have no idea what to get between 9 - 9.5 ???
I am running a Procharger P1 with 50 or so shot of Nitrous.
Any help here?
i dont have a blower im turbo'd i have a phamspeed kit,with a T67 as of right now but im going to need to upgrade in the future cause the poor turbo cant handle a forged 383.im curious how my GT2-3 cam would do with that setup or if i need a bigger boost cam.
Originally Posted by ddnspider
i dont have a blower im turbo'd i have a phamspeed kit,with a T67 as of right now but im going to need to upgrade in the future cause the poor turbo cant handle a forged 383.im curious how my GT2-3 cam would do with that setup or if i need a bigger boost cam.
A bit bigger wouldn't hurt. My 224/224 114 seemed to work decent. I think I want to go to something like 224/227 114
