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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Check out this new Dual Plenum Intake Manifold offering from Shearer Fabrications! The Holley Hi-Ram is King Kong in LS high rpm hp production, but the extra tall Hi-Ram lid has been a pain to fit in the C6 platform. Hats off to Shearer for the innovation. I thought about this approach to using a Hi-Ram several months ago but obviously my fab skills are lacking. It's a cool looking piece that I'm sure functions well. Very tempting!
I'm curious how a Shearer would compare to a Mamo MSD on a big inch NA motor, I'm guessing no less than 10rwhp, no more than 25rwhp, with an equal number of foot pounds being subtracted below 6500 rpm. If I ever did something like this I would ask Tony Mamo to bless it with some porting.
I'm a perpetual tinkerer so I might try this in the future. It would require a new hood obviously, but it's exciting to have a new intake manifold option for people who don't want extreme hoods. Unreal mentioned this to me in a separate thread and I just wanted to share in case anyone hasn't seen this....too cool!
Josh
From Shearer Fabrications: "I'm excited to finally introduce our new Dual Plenum Intake for the LS engines. Our modifications to the proven Holley Hi-Ram intake manifold have made a great intake even better! The Dual Plenum design moves the throttle body under the plenum for tons of additional hood clearance while feeding the main plenum with a linear airflow for improved air distribution among all of the cylinders. Runner length remains unchanged for optimal performance, torque and driveability.
This has been tested on a TT C6 Corvette to 1200whp with great success. While it does not fit under a stock C6 hood it will fit under a very short cowl hood to keep that classy appearance. We will begin verifying hood clearance on different vehicles in the coming weeks.
We are ready to start taking orders for these, however we are putting the final details and pricing together as we speak. They will come with a CNC machined billet lid and optional powder coating. Target pricing is in the $1500-1700 price range."
Interesting indeed. Never would've though the TB placement underneath would have enough room. Would also love to see one with the lid removed...curious how wide the intake "trough" is, as looking the inside of an untouched high ram...the runners aren't that far apart from right to left.
I am curious about the "trough" width too. I'm sure it's wide enough to flow like crazy. The dual plenum looks like a real PITA to physically get a torch in there and weld to the Hi-Ram, unless they just welded at the trough in a single seam. Their fabricators must be have some crazy skills.
I'm also curious how a dual plenum might behave with reversion, more less or the same as a traditional plenum plastic manifold.
High speed columns of air don't like dramatic changes in direction.....this design is requiring it to essentially make a 90' degree move upward from the front of the engine into the plenum area.....then a far worse 180 degree turn from the plenum to the runners.....then an additional 75 ish degree turn from the straight up tall runner exits to the intake ports of the head.
Follow the flow of air from what would be your CAI of choice in front of the TB to better follow what Im getting at but as a cylinder head and intake manifold designer by trade, I don't like all the directional changes this design requires (mainly due to packaging restraints).
And as Turbo2L picked up on, this isn't going to fit under a stock hood
BUT.....sometimes theory and real world net different results and Im always game for outside the box thinking so Im curious to see the real world results of this design regardless of the fact most guys would cross it off the list for the cowl height / hood modifications required to clear it.
I'm probably going to try one. I've known Ron for a long long time.
No idea if this would work well on a N/A setup, but on the 1200+hp cars it showed no difference between the normal high ram.
Doesn't fit a stock hood, but fits any of the hoods made for a TVS setup, which at least opens up a ton of options. While the air turns are not ideal, hard to judge what effect they have. All the testing so far shows no down sides on boosted setups.
Audi runs a similar dual plenum setup on their lemans cars. HKS has been doing it on 4 cylinder cars for awhile with great results.
Picture of a Lehmans intake setup that shows how the slot from one plenum feeds the other.
Was thinking along similar lines as Tony with respect to the all the changes in direction of airflow; but I also thought that under boost, the air is forced to go wherever its told. NA would be interesting to see.
He posted a picture with the lid off last night. It may still be floating around the internet. I ran Shearer manifolds on my DSMs and EVO. He's pretty slick when it comes to sticking metal together.
He posted a picture with the lid off last night. It may still be floating around the internet. I ran Shearer manifolds on my DSMs and EVO. He's pretty slick when it comes to sticking metal together.
Was thinking along similar lines as Tony with respect to the all the changes in direction of airflow; but I also thought that under boost, the air is forced to go wherever its told. NA would be interesting to see.
Common misconception is that boosted engines work better or differently than N/A engines....even among shops and guys in the industry, its a very common misconception.
"N/A motors suck air and with boosted engines the air is pressurized and forced into the engine"....you hear (and read) alot of that and its not true guys. It all works the same....and N/A engine is "pressurized" also but its only pressurized with the weight of one atmosphere of air versus one atmosphere plus 50% (7 PSI ish) or two atmospheres (14 PSI ish) etc. etc.
It all works the same....air is being forced into the engine in both situations....all the dynamics of an N/A engine apply to boosted engines....but with boosted engines there is more force and higher airspeeds occurring because of that situation and technically that can change things but its very subtle.
Quick story.....awhile back a customer of mine swapped out my ported FAST for a sheet metal intake of some kind. It obliterated the power curve giving up 50 ft/bs of torque down low and barely making the same peak power (it was actually a few HP less). As soon as he drove the car with the sheet metal he knew it was bad before even hitting the dyno (he had already done some street tuning to get the AFR's close).
He shelved that intake shortly after and a few years later he went boosted (A&A Supercharger set-up). He was so convinced that sheet metal intake was going to work great under boosted conditions (in light of my sharing why I didnt think so). I was curious but felt not much would change. Sure enough he swapped it right on the dyno this time and the same end results....obviously he made a bunch more power with both intakes due to the supercharger install, but the sheet metal intake just killed the area under the curve once again.
(This time the intake was finally up for sale though.....LOL)
True story....real world example of the fact there is very little changing in the dynamics and hot ridding principles of an engine N/A versus boosted with the obvious exception of cam design to help crutch evacuating the cylinder from the larger intake charge the blower provides.
My question is would this intake work better with a higher than plenum height TB/inlet location and I think it would but it certainly wouldn't package as well and this intake doesnt need a monster hoodscoop to work where the other situation I just mentioned clearly would.
Hell I'm looking forward to the testing....I would even provide a ported MSD to compare it to as that's the best "conventional style" LS7 intake on the market presently....it would make for a really cool test comparing the shape of the power and torque curves and honestly these intakes for the most part appeal to two totally different crowds but it would be cool to see the difference between the two.
-Tony
Last edited by Tony @ Mamo Motorsports; 04-06-2017 at 10:17 PM.
Tony, I know you think otherwise but I just don't see a MSD holding up to 25+psi of repeated abuse. My stock intake is starting to crack, which is why I'm looking at options. The stock ls7 plastic intake is beefy, and yet is still starting to come apart, which is why I want something a bit more robust.
I won't do one of the short runner intakes because of exactly what Tony said above. All I've seen is them give up a ton of power down low, to maybe make a bit more up top. Unless it is a 6-8k motor with an auto that lives up there, they slow the cars down. This keeps the long runner length and a lot of the good parts of the high ram, while cutting down the needed clearance by 3"+. The slot has more cross section than the TB, so it shouldn't be any more limiting than the TB is.
Its really just the hood thing holding me back. I got $3600 into this LG hood and really don't want to give it away. If I can get a reasonable price for it, I'll do it for sure. The hood I think I want is ~$2300ish, so that plus $1600 for this, + fuel lines+etc etc will be an east $4k+.
Quick story.....awhile back a customer of mine swapped out my ported FAST for a sheet metal intake of some kind. It obliterated the power curve giving up 50 ft/bs of torque down low and barely making the same peak power (it was actually a few HP less). As soon as he drove the car with the sheet metal he knew it was bad before even hitting the dyno (he had already done some street tuning to get the AFR's close).
-Tony
This video with Tom Nelson is couple years old but still relevant to this discussion. At 13:30 he talks about intake manifolds, specifically sheetmetal intakes.
"People spend thousands of dollars to lose lots of horse power"
It's hard to argue with a guy who has an engine dyno!
04-06-2017, 05:46 PM
Shearer Fabrications Intake Manifold
