Another "How much will it make?" Project "Special Needs"

[CGT]

Id like to see the results , or atleast know the combo it went on, <specifics> were all the manifolds stock, head csa, cross over points of each manifold, i dont know the csa of a hurricane but if both the motown and 2814 were stock i could see the 2814 not turning on till later in the curve then the motown, motown is smaller out of the box, im interested in the 6600-8000 rpm range , but post what ya gotTom

I believe the results were posted on here, its been a few years. I'll see if I can dig the thread up. 383, 5.5 rod, 10.5 comp, small port BV ported by Randy331, Braswell Carb, 230ish hyd roller with .600 lift. All manifolds were prepped by Randy. Pulls were made mostly from 3000-6500, but I did make quite a few pulls to 7000. Lot of dyno pulls made.

[Rick360]

I didn't see a tunnel ram on that list to test ??????

Randy

Did someone say TUNNEL RAM? Here's one that has a little porting done but is a few years old. Could be borrowed for testing or purchased for a very reasonable sum.

This would be the hot ticket for a special needs project.

Rick

[CGT]

That's entirely too ugly to go on Special Needs. Would make a unique flower pot though!!

[RevTheory]

Not nearly enough plenum volume!

[randy331]

That's entirely too ugly to go on Special Needs. Would make a unique flower pot though!!

Don't waste it planting flowers, use it on your tow truck!!

Randy

[CGT]

So, any horsepower and torque predictions out there? Additional valve timing suggestions?

[randy331]

So, any horsepower and torque predictions out there? Additional valve timing suggestions?

I didn't see the " much needed low lift flowZ " posted ??

Be hard to predict power without thoZe.

Randy

[CGT]

So, no predictions or suggestions besides a tunnel ram or blower that wont clear my stock hood?

[randy331]

Large Port BV epoxied down. 2.08 1.56

Your valve sizes, cubes, and compression is the main reasons I suggested the cam that I did. Using flow numbers, and especially just peak flow numbers, to spec a cam doesn't make sense. Why would flow at the installed intake centerline ( 102*-110* atdc or so ) have anything to do with the decision to add or reduce duration? In other words, the decision to keep the valve open later ABDC, or to open it earlier BTDC??

When I dynoed an engine with that intake, it liked a 2 inch tapered spacer. Got room under the hood for one?

Your power goals seem realistic.

Randy

[CGT]

Why would flow at the installed intake centerline ( 102*-110* atdc or so ) have anything to do with the decision to add or reduce duration? In other words, the decision to keep the valve open later ABDC, or to open it earlier BTDC??

Assumptions would have to be made as to what the rest of the flow curve on either side of that peak flow looks like, along with what those numbers look like with an intake manifold attached, and if that flow going in the correct direction was directly related to flow going in the wrong direction (reversion), which it is.

When I dynoed an engine with that intake, it liked a 2 inch tapered spacer. Got room under the hood for one?

Highly unlikely, actually a little worried about getting the manifold itself under the hood, but maybe I'll get lucky and be able to run one. I'll definitely be trying one on the dyno.

Your power goals seem realistic.

My goal is approaching 1.38ft/lbs of torque per cube, and over 1.5hp per cube. I hope your right.

[RevTheory]

I think the low-lift flow (what's seen during TDC/overlap) is really important for determining IVO and EVC and ultimately, LSA. Others obviously don't see it that way.

[CGT]

I think the low-lift flow (what's seen during TDC/overlap) is really important for determining IVO and EVC and ultimately, LSA. Others obviously don't see it that way.

I see LSA being a somewhat side effect of getting the two valve events you didn't mention in the ballpark of where they need to be. I think low lift flow is important, important to limit it.

[randy331]

I think the low-lift flow (what's seen during TDC/overlap) is really important for determining IVO and EVC and ultimately, LSA. Others obviously don't see it that way.

How do you go about deciding how much of in vs ex low lift flow you need and when one is optimal and the other is high or low?

In other words, how do you decide I'm gonna add duration or take duration away from either the ex or intake?

If we have the whole flow curve of both in and ex, how do we look at that curve and decide the intake is weak/strong or the ex is weak/strong vs the other one, vs the application?

Randy

[RevTheory]

I think the low-lift flow (what's seen during TDC/overlap) is really important for determining IVO and EVC and ultimately, LSA. Others obviously don't see it that way.

How do you go about deciding how much of in vs ex low lift flow you need and when one is optimal and the other is high or low?

In other words, how do you decide I'm gonna add duration or take duration away from either the ex or intake?

If we have the whole flow curve of both in and ex, how do we look at that curve and decide the intake is weak/strong or the ex is weak/strong vs the other one, vs the application?

Randy

I've read your posts over the years and I know where you stand so I'm not going to allow myself to be drawn in. I'll just tell you in generalities what *I* look at and leave it there.

I like to see the Cd at .100 and base my math on 65%. I also look at the exhaust to intake flow differential from .100 on up to help decide on what I think is the right exhaust lobe. Depending on how it changes throughout the lift curve, I can get an idea of whether or not to add/subtract duration, rocker ratio or leave it be and change the lobe symmetry. Single-pattern is my baseline.

I would never intentionally kill low-lift flow on an engine operating at this rpm. In my opinion, this engine needs ~275 cfm at max lift and ~155 cfm during the overlap period to reach his hp goal.

[sjre]

Randy, new here, dont have any experience picking cams but I can almost understand 228 jnt. (but for 6000+ ?) also the 112 cl but I cant understand the 20+ more exh duration for a street car w/exhaust .
Is it because of a low i/e percent or to help it hang on longer with higher cyl pressure at both low and high rpm? Please if you want explain. Ive seen 258 at 50/110 on a 496 bbc top at 6300, 267 @ 50/108 top at 6400/ 396 sbc,275@50/108 522 mopar at 6000all had 6-8 deg. more exh.I could never figure this out even with good heads or did they need more duration/ wider cl but these were recommended for their apps. I have read several of your builds and they are very impressive .Just trying to learn a little.
thanks Joe