jester1

iTrader: (1)

Hi guys
Im building a turbo motor whic started out as a nitrous motor.
355ci
vcjr coverted to efi
proted pro 1s
8.5:1 - 9:1cr
4340 bottom end
and the clinthcer 256/264 @50 610/630 lift solid roller
what do you think of this?
now the poweradder either: t76/t88 or novi 2000/ t-trim @20lbs bst
sounds like a 7200rpm motor should I asume this is correct
thanks!

JZ 97 SS 1500

iTrader: (2)

What is the LS of the cam??

Jose

eviltwins

My old cam was 238/232 with a little bit more lift that you listed there. Remember turbos carry the power a lot higher into the powerband than a naturally aspirated car does, so if you have a N/A cam for a 6500 RPM motor you could expect that to still be making power at 7500 with turbos. Too big IMO, you'd get better results with less duration.

jester1

iTrader: (1)

I knew I forgot something , the lobe sep is 112 deg.

y2khawk

iTrader: (5)

uggg

My old cam was punny, 228/224 112 LSA less than .550 lift

It made decent power, but was kinda peaky. And real doggy down low/off boost.

My new cam
251/248 .690 LSA 115 ICL 113

power is flat and broad, but we've yet to find the peak. It just keeps climbing, at least at 7200 it does.

Don't know about 20 psi though, it just spun the tires on the dyno at 18

Jammer

iTrader: (1)

sound to big for me....Im no cam expert but my two cents keeps you in the mid 230's on both I and E and lift in the low 600's

y2khawk

iTrader: (5)

for reference

We had a 230/230 LSA 114 .620 lift hyd cam in a 355 LTI, LT4 manifold, 15 psi that made 750 RHWP on a mustang dyno.

We just up'd that to a 242/242 LSA 115 .690 solid roller.

It's not too big, if you plan to spin the **** out of it

But you could go smaller, make the same or similar power in a more sane RPM range.

something to think about

jester1

iTrader: (1)

y2khawk- is the 242-242 newer than the 251/248,
what rpm did that 355 run at? did you ever see where the 251 cam/rpm range ended?

y2khawk

iTrader: (5)

different motors

we spun the LT1 to 7000 with the 230/230

on the dyno, we never found the peak w/ the 251

eviltwins

What size of turbo was that with?

jester1

iTrader: (1)

Will insufficient head flow drop the rpm peak? Why use a cam with less exhaust duraion than intake?

y2khawk

iTrader: (5)

That was a pair of 60-1 Hi-Fi's, our log style manifolds, and AFR 220 heads with their CNC port job.

y2khawk

iTrader: (5)

poor flowing heads will make the turbos work harder, ie more boost for a given flow.

The single versus reverse spilt versus traditional split pattern has been hashed here before. My personal thing with it is, get all the intake charge in the motor you can w/ the longer intake duration and keep the exhaust shorter to keep the exhaust energy up. Since you're fighting a large backpressure on the hot side it makes sense to me to keep the valve open time to a minimum and get it out quick.

I'm no cam expert by any means, but the reverse seems to work for me.

RICE ETR

iTrader: (3)

Harlan,

I am running the 227/224 cam for the same reasons you mentioned... makes sense to me.... but sometimes i wonder if it is too aggressive? I am stepping up to a T76 and a/w IC as I am out of turbo now... so I hope this cam will work with more boost, do you think I should put something milder in? I am shooting for 650rwhp+

y2khawk

iTrader: (5)

What's the LSA on it?

Don't get me wrong, my 228/224 made 700+ RWHP on a mustang dyno at 15 psi and went 143+ @3600 lbs, it worked. Just wasn't optimal w/ the 112 LSA. I would have liked a wider power band, but would have had to spin it a little more to get the peak.

Jammer

iTrader: (1)

Im also running a rev split for all the reasons mentioned above. (w/ 115 LSA, 230/226)

RICE ETR

iTrader: (3)

114 ..... so what do ya think?


Thanks