SuperL98

Corvette Enthusiast Magazine (October 2010) did a nice manifold comparison on a 350 Chevy this month.
First, I’m NOT going to post the whole article here, because it’s a fairly good Corvette Magazine and we should go out and buy copies to support them (or I’m sure they will post it on the web in time).
But I did put the results in graph form so it’s easier to compare (they only listed them in print form), and will post them up here.

Test Engine Specifications:
355 Chevy
6.0 inch rod
GM Vortec Heads – Ported – 278 CFM Intake 210 CFM Exhaust
2.02/1.60 valves
10.95:1 Compression
Dyno headers
1:6 ratio Intake & 1:5 ratio Exhaust roller rockers

Cam One: 210/220 Duration @ .050 - 0.332/0.342 Lobe Lift – 114 Lobe Centerline
Cam Two: 226/234 Duration @ .050 – 0.353/0.355 Lobe Lift – 112 Lobe Centerline

Manifolds Tested:
TPI = Accel large tube runners - Scoggin Dickey Vortec TPI base – 58mm Tb
Holley single plane EFI manifold – 750 CFM Tb
GM RamJet EFI manifold – 75 mm single Tb
Holley Stealth Ram EFI manifold – 58 mm Tb




Interesting?

TheCorvetteKid

Odd that the TPiS MiniRam wasn't tested with this batch. I guess maybe it's been tested to death...? Still, it would have been really nice to see how it stacked up to the ones tested in the article.

GREGGPENN

Thanks for posting the results -- especially in graph form. I was a hair surprised and the midrange results of the single plane vs the HSR. But, I was more surprised by the amount of extra torque available to the TPI vs the other intakes particulary below 3000 rpms. But, dynos aren't always as accurate down that low.

It should be noted how well the ported Vortecs did in this test. I would predict/estimate results from other favorite aftermarket heads not much better than this. (wink, wink, nudge, nudge, know what I mean?!)

I also posted the actual lift numbers with the rocker ratios applied. That way no one else has to do the math.

Not really. I bet Holley, GM, SD, and/or Accel are bigger contributers to the magazine. It's that simple. More importantly, the absence of the MR isn't worth noting since it's results can be easily predicted by comparing how the MR performed (vs the other intakes) in the TPI Shootout article so often posted/linked here.

Thanks again SuperL98 for posting this data. Is the part of the C4 strip-down I recently saw...Or is this an independant comparison?

JAKE

I hope cynicism isn't contagious, LOL

Interesting too, the TBs that were used in the tests.

Jake

SuperL98

Left this out.

From the article:
The Holley single plane has 8 inch end runners, and 7.5 inch center runners.
The GM RamJet runners are 5.75 long.
The Holley Stealth Ram has 7 inch runners.

So (according to the article) the Holley single plane has longer runners than the other two (not counting the TPI setup), which might explain the better torque with the smaller Cam1.

GREGGPENN

I missed that. 58mm on a TPI, 750cfm on the single plane, and 75mm on the RamJet. Talk about controlling the "experiment"!

Orr89rocz

SIngle planes are very similar to miniram's and HSR's and any shorter runner intake for that matter. After owning both SP and HSR, its easy to see why. Runners are near the same length with slightly longer ones going to HSR. I dont know where they are measuring for the holley single plane, but I dont think my victor E doesnt have 8" long runners.

A single 75mm TB (LSx style) will flow about as good as a 52mm twin setup (TPI style) which is about 760 cfm. 75mm has abit more flow, around 780cfm.

On the bigger cams, the HSR will have the advantage with its 58mm TB. Wont choke it as bad.


But this is an interesting article in that they used near 11 to 1 compression on IRON heads with that small cam (either one is too small for that compression and pump gas). I really dont think this motor would run too happy on pump gas, you'd have to be very very careful on the tune/timing this motor would see.

YOu can see how the heads are choking this setup or they are having some valve float. That bigger cam doesnt pull any higher rpm than the smaller one, and it should peak alittle higher than 5800 rpm

SuperL98

I’ll be darned, the whole magazine is on the web

http://editions.amospublishing.com/K...spx?d=20101001

Article is on Page 75

ch@0s

Very
Thanks for posting this.I really wish they would have included the Miniram as well.

kenv

, Thanks!

rklessdriver

You guys will never learn. These sell out rag "test" are nothing more than shams to drum up sales/business for what ever product the supporting vendor for the test wants to sell.

In this case it appears Holley needs to sell some HSR's.

Will

dclafleur

Will the ramjet even fit under our hoods?

mcm95403

Having worked at Flowmaster for 2 1/2 years, I have to agree with you. We got HAMMERED for a few years about a street muffler shootout that had been done by Car Craft and they allowed Borla to submit race mufflers for the test. They were WAY louder than ours and yes, they made 1 or 2 more peak hp. The VP of Sales and Marketing (Richard Small) called us all into his office one afternoon when one of the guys from CC called asking aobut mufflers for another shootout. Keep in mind this was after we'd become THE muffler to use. Of course Richard hammered him about the last test. The guy flat-out told Richard that they would run the test and then send him the article and that if he didn't like it they wouldn't print it. Richard told him that if they were that easy to buy off that they could go to Super Shops and buy a set of mufflers 'cause he sure wasn't going to send them any. End of call.

Just like anything where advertising keeps your doors open - it's pretty tough to be on the up and up.

mgroshong

I always take dyno "shootouts" from mags with a grain of salt. And It's pretty obvious who is behind the test numbers most of the time. It happens like crazy in the import mags.