split or single pattern cam?
split or single pattern cam? anyone care to list the cam they are using?
i remember reading a while time ago about some specs but the search isnt working atm so anyone want to post up
114+ lsa
Turbo only.
i remember reading a while time ago about some specs but the search isnt working atm so anyone want to post up
114+ lsa
Turbo only.
On The Tree
Joined: Mar 2006
Posts: 112
Likes: 0
From: N.C.
I'm using a straight pattern cam 235/235 114lsa boost/backpressure 1:1
it was a 255/262 114. it had an insane powerband above 5000rpm
I'd say reverse splits for small turbine
straight pattern for low(?) backpressure
mild split patterns for drag
I have a friend who ports heads for a living who sez some turbo engines like lots of overlap and or low lsa. also to install it "straight up". no advance.
way too many variables to make blanket statements.
it seems everyone with a turbo tries multiple cams
flamesuit: ON
it was a 255/262 114. it had an insane powerband above 5000rpm
I'd say reverse splits for small turbine
straight pattern for low(?) backpressure
mild split patterns for drag
I have a friend who ports heads for a living who sez some turbo engines like lots of overlap and or low lsa. also to install it "straight up". no advance.
way too many variables to make blanket statements.
it seems everyone with a turbo tries multiple cams
flamesuit: ON
TECH Addict
Joined: Jul 2005
Posts: 2,153
Likes: 3
Originally Posted by stevieturbo
so which was it ??? 235/235 or 255/262 ???
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
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
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Originally Posted by Pro Stock John
1:1 backpressure sounds pretty good right.
I was under the beleif, if you can obtain 1:1 or indeed less...thats ht ekey to making huge amounts of power, and is how the old turbocharged 1500cc F1 engines made so much power.
In qualifying trim, they were making around 1500bhp from a 1500cc engine. Not too shabby.
Originally Posted by engineermike
He started out with a 255/262, then later switched to 235/235. The backpressure/boost ratio with the big cam was 1:1. I'm curious if the backpressure/boost ratio changed with the smaller cam. I have a crazy theory about alot of overlap actually helping the boost and backpressures equalize.
go on...
TECH Addict
Joined: Jul 2005
Posts: 2,153
Likes: 3
Originally Posted by stevieturbo
Not if its at the expense of EGBP bleeding into the intake charge, although its unlikely.
By shortening duration, the Backpressure/boost ratio might go from 1:1 to 1.5:1 but gain hp in the process.
This is just a theory.
Mike
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Until you can achieve a PR of 1:1 or less, I cant see any reason why you would want overlap ( using that term loosely ), to allow exhaust gases to enter the cylinder, or even worse, the plenum.
TECH Addict
Joined: Jul 2005
Posts: 2,153
Likes: 3
stevie, I used to believe the same thing. However, a few dyno tests that I've seen seem to indicate otherwise. For instance, INTMD8 did more turbo cam testing than any one else I've seen. He tried at least 4, maybe 5 different cams on his 850 rwhp twin turbo LTx. He was running a 2/1 backpressure ratio and every time he added overlap, it gained power. I would be very interested to see just how far you could go with it, though.
Another aspect to Intmd8's LT1 project car is that he's been going for as refined a combination as possible. Mike, I recall that he's swapped out cams that made more power for milder cams, but did that to increase the driveability.