Increasing intake air flow on a LT5

[Norwegianmopar]

Does anyone know if Vararam or other brands make any intake air duct systems that increases the air flow to a ZR-1 (or other C4's)?

As you all know the intake duct is not the most free flowing and straight forward on any Corvette, and I know many have upgraded their C5, C6 and C7 models, but I have not found anything about the C4...

If anyone has experience or knowledge on this area please let me know.

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[rush91]

There are a few options I know of....

http://www.jerrysgaskets.com/duct-silicone-air-inlet-black-red-blue-90-95-12a/

http://zr1specialist.com/HAT%20Web/products/hoops.htm

[DRM500RUBYZR-1]

Buy another stock air filter lid from any later C-4, very inexpensive.


Lay it on your work bench.


Put the filter in it.


Trace a line where the filter sits.


Remove the filter.


Get your tin-snips.


Remove all of the metal within the traced line.


Once that is complete.


Take a large coffee can or piece of metal.


Form it into the shape that will fit within the air duct.


Install it in your air duct.
Put it all back together.


You may then assert that it increases your horsepower and torque by some crazy number, but it will actually increase the air flow, and prevent the duct from collapsing.
And, best of all it does not cost $800.00, nor does it increase the chance of ingesting water into your intake air stream, like some of the expensive solutions.
More elegant solutions are out there, but in the meantime while searching them out, the above will work.
Marty

[Norwegianmopar]

There are a few options I know of....

http://www.jerrysgaskets.com/duct-silicone-air-inlet-black-red-blue-90-95-12a/

http://zr1specialist.com/HAT%20Web/products/hoops.htmOh I mean getting the air from the inlet under the nose and up in to the filter and intake. Not replacement parts like these. Maybe I did not explain good enough what I'm looking for...

Originally it goes in like thru a S-shaped duct, kinda like "zig zagging" up to the air filter box, not exactly free flow there.

There are headers and free flowing exhaust systems out there, but I can't find anything to improve the air flow in from the front to the intake...so the power is limited by the amount of air you can get in.

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[Norwegianmopar]

Buy another stock air filter lid from any later C-4, very inexpensive.


Lay it on your work bench.


Put the filter in it.


Trace a line where the filter sits.


Remove the filter.


Get your tin-snips.


Remove all of the metal within the traced line.


Once that is complete.


Take a large coffee can or piece of metal.


Form it into the shape that will fit within the air duct.


Install it in your air duct.
Put it all back together.


You may then assert that it increases your horsepower and torque by some crazy number, but it will actually increase the air flow, and prevent the duct from collapsing.
And, best of all it does not cost $800.00, nor does it increase the chance of ingesting water into your intake air stream, like some of the expensive solutions.
More elegant solutions are out there, but in the meantime while searching them out, the above will work.
MartyInteresting Marty. My buddy and I were brainstorming a bit today regarding this. He has a modified C6 Z06 and use Vararam products. I emailed them and was told 5 min ago they have not been able to come up with any good solutions for C4 Corvettes...

Knowing the LT5 has huge potensial we are trying to find a good way to get more air into it, without turbos etc.

He can map and calibrate chips etc at his shop, so the fine tuning is no problem, just getting all that cold air out there in effectively..

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[We Gone]

Not that I would but you can reverse the air filter, cut a hole in the shroud and let it pull air from in front of the radiator

[Norwegianmopar]

Not that I would but you can reverse the air filter, cut a hole in the shroud and let it pull air from in front of the radiatorWould not do that either. Cold air from the front with less restriction would be the case...if we can figure it out.

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[lfalzarano]

Buy a SLP claw intake and save your original air filter assembly for originality in the future.


Lou

[Paul Workman]

The "choke points" for air flow and the 95 rwph increase while maintaining the stock TB and cams didn't come from fussing with the intake/filter box. It came from porting, headers, SW "X" pipe and 3" exhausts.

OK, I had a K&N air box which exposes the air filter on top of the box, but with that and stock exhaust and Borla mufflers, it dynoed at 337 rwhp (now at 432, last time on the dyno).

If you open the runners to 36mm min on both the primary and secondary runners and taper the inlet to the heads from 36mm at the input to blend with the stock dimensions at or near the valve guide bosses, that alone will make an entirely different animal out of you LT5 and you won't have to pull the heads to do it either! (But, you WILL need a new tune, however!)

[Norwegianmopar]

The "choke points" for air flow and the 95 rwph increase while maintaining the stock TB and cams didn't come from fussing with the intake/filter box. It came from porting, headers, SW "X" pipe and 3" exhausts.

OK, I had a K&N air box which exposes the air filter on top of the box, but with that and stock exhaust and Borla mufflers, it dynoed at 337 rwhp (now at 432, last time on the dyno).

If you open the runners to 36mm min on both the primary and secondary runners and taper the inlet to the heads from 36mm at the input to blend with the stock dimensions at or near the valve guide bosses, that alone will make an entirely different animal out of you LT5 and you won't have to pull the heads to do it either! (But, you WILL need a new tune, however!)Interesting, Paul.

I have original exhaust with Borla mufflers, but will replace the center resonator with a x-pipe due to it being worn out and welded twice.

On a side note, I installed a new fuel filter today, and it became a monster from 5000 and up. It was fast before (had it for 2 months now and driven over 3500 miles), but man it went wild now. Probably never got what it should on full throttle before. All the small stuff adds up alright.

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[onethumb]

Buy a SLP claw intake and save your original air filter assembly for originality in the future.


Lou

It seems that the issue at hand is not the intake itself, but the path of air to the intake. I've always thought that these sort of intakes just suck hot engine compartment air it rather than cooler outside air, thus negating any benefit from having a larger filter area and less resistance.

Or am I reading this wrong?

[aafc]

Ok i have been playing with 3 types of air intake systems.
The first one was the A/O Forced Air system,but the inlet to the hose is almost
cut in 1/3 size.
Number two. By using the hole made by the forced air system i made a scoop up to an open air filter lid.
Now my last one is a copy of the "PRO STOCK" system used by NHRA Pro
stock class. I made a tube out of alu hand formed to the stock air bridge(with reinforced insert ) and ready a 4 in 90 deg PVC fitting to witch i connected a cone shaped filter mounted inside the front bumper.
I still have to run tests to see if i have enough air to the motor.

http://www.zr1.net/forum/picture.php?albumid=430&pictureid=3793

http://www.zr1.net/forum/picture.php?albumid=430&pictureid=3789

http://www.zr1.net/forum/picture.php?albumid=430&pictureid=3792


This may not be good for most people,but if you cut a hole into front of your
car. You can try anything.

1990 #2546 white/black
one of a few auto 4l8OE eq ZR-1's
thanks
John

[Ccmano]

I had Vararam’s on both of my C6’s and the affect on engine power was noticeable. My 08’ LS3 achieved 400rwhp with simply the Vararam and a canned tune.

That said I do not believe similar gains can be achieved on an LT5. The air filter system is simply not that restrictive. I use a K&N with an open lid and I remove the water barrier below the filter housing which allows more direct airflow. Still I doubt it makes a big diffence. I haven’t been able to find it but I believe someone did a comparison a few years ago between stock, a K&N, a mod like mine, a claw and possibly even the now discontinued ram air system that fed though a hole in the license plate cutout in the bumper.

As Paul has already said, the big gains are in the plenum/injector housing/head porting and headers.
H
:cheers:

[Ccmano]

Found it... over on Corvette forum. Dyno results included.

https://www.corvetteforum.com/forums/c4-tech-performance/1315330-air-intake-dyno-results.html

H
:cheers:

[Norwegianmopar]

It seems that the issue at hand is not the intake itself, but the path of air to the intake. I've always thought that these sort of intakes just suck hot engine compartment air it rather than cooler outside air, thus negating any benefit from having a larger filter area and less resistance.

Or am I reading this wrong?You are reading my question spot on.

Vararam emailed me yesterday and said this about my question about them having any systems for C4 Corvettes:

"Sorry - no - we have looked at them but can't find an effective way to make one."

Knowing there is a bunch of skilled and experienced members in this group I decided to make this thread.

Vis sitert tekst



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[Norwegianmopar]

I had Vararam’s on both of my C6’s and the affect on engine power was noticeable. My 08’ LS3 achieved 400rwhp with simply the Vararam and a canned tune.

That said I do not believe similar gains can be achieved on an LT5. The air filter system is simply not that restrictive. I use a K&N with an open lid and I remove the water barrier below the filter housing which allows more direct airflow. Still I doubt it makes a big diffence. I haven’t been able to find it but I believe someone did a comparison a few years ago between stock, a K&N, a mod like mine, a claw and possibly even the now discontinued ram air system that fed though a hole in the license plate cutout in the bumper.

As Paul has already said, the big gains are in the plenum/injector housing/head porting and headers.
H
:cheers:It's not the air filter system that we think is the restrictive part, rather the way the air has to travel to get to the filter box. The duct leading to the filter box is not in a straight line, but kinda S-shaped or zig zagging if you like.

This makes ram air effect hard to get; more cold air in as the speed increases. We believe there has to be a way to achieve this.

Imagine being able to get more cold air in and thus being able to get more fuel burned. Add this to the porting and headers etc in the other end of the power plant. In theory, that should bode for even more power gains than with today's amount of air getting in thru the existing intake system. Agree..?

We all know twin turbos or superchargers can help with this, but not for the same $$$ [emoji16]

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[Norwegianmopar]

Found it... over on Corvette forum. Dyno results included.

https://www.corvetteforum.com/forums/c4-tech-performance/1315330-air-intake-dyno-results.html

H
:cheers:Yes I have read this thread too [emoji106][emoji4]

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[Norwegianmopar]

This is the type of system I would love to have on my Z:

http://www.vararam.com/b2.html

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[efnfast]

I would think some way to measure vacuum at the horn would tell you if there was enough restriction to matter.

[DRM500RUBYZR-1]

This is the type of system I would love to have on my Z:

http://www.vararam.com/b2.html

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40 Horsepower add?


Marty

[Norwegianmopar]

40 Horsepower add?


MartyThey say so. More air in equals more fuel can be burnt, and more horsepower as a result.

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[A26B]

Personally, I'm not a believer in any measurable power gain from so called ram air. Quite a bit of dyno testing has occurred over the years, comparing the paper element air filter, K&N filters and no filter. I have had my car on the dyno, testing the front bumper air inlet system, with & without the paper element and even with no air filter system attached to the air horn.

K&N vs standard paper element : no difference
AO Engineering bumper air intake: 2~3 Hp loss
"Ram Air": Virtually negligible at typical hwy speed
Stock filter lid vs detached filter box: no measurable difference

Cold ambient air does make a difference. Greater air density = more O2
Moving IAT sensor to filter housing: avoids sensor heat soak, possibly more accurate reading. Less heat transfer to incoming air occurs, due simply to an increase in air velocity. The plastic portion of the air intake system doesn't heat soak like metal engine components which are first encountered at the throttle body.

Considering where a Corvette gets air, down low, close to the pavement, regardless of what type of system you believe in, it's getting the hottest air, right off the pavement.

Stock system friction loss: I've never bothered to do the math, but I expect it would yield a number well in excess of the air volume required for a stock engine at high rpm & speed.

The meager testing performed with my ZR-1 is with a 415 engine. That's 65c.i. more or 18% greater volume than a stock displacement LT5. If you don't see much with a 415, you're not going to see much with a 350.

In summary, I think there's more power to be had with other modifications at a lower cost/Hp. A serious look at reducing under-hood heat by better ambient air flow may do more good than air intake systems with bogus increased Hp claims.

[A26B]

They say so. More air in equals more fuel can be burnt, and more horsepower as a result.

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The engine is essentially a positive displacement air pump. Normally aspirated & from a practical perspective, there's only a "fixed" amount of air going through the engine.


The only way you are going to efficiently burn more fuel, is to add more oxygen by increasing air density, which is accomplished by increasing air pressure or decreasing air temperature. That's what nitrous oxide does.


You are never going to make much difference with filters, cut lids, claws, bumper air intakes, etc.

[DRM500RUBYZR-1]

But Jerry,


It says right in the ad.


40 Horsepower!


You mean,


NO...................


You mean it might not be 40?


I don't think my cams added 40.
Guess I should have gone with their solution........................
Marty

[TX '90 ZR1]

But Jerry,


It says right in the ad.


40 Horsepower!


You mean,


NO...................


You mean it might not be 40?


I don't think my cams added 40.
Guess I should have gone with their solution........................
Marty

And it says right there in vivid color a guaranteed 3 10th's to 1/2 second decrease in ET! Guaranteed!!!
:blahblah:

[Vette73]

Dempseys dragon heart package or Haibecks 510 package ...Take your pick...Even little gains on an engine that's making 385-400 CHP your not going to feel..

[XfireZ51]

You can add Dr. Greekenstein’s 350 or his new 391 monster package to the list of options.

[rkreigh]

jeal had a gourgeous carbon fiber intake and there have been some custom air boxes fabbed up which may help


the factory air box and filter are good to 700 hp so once you pass that number please let me know and we can work on a better air box


it's just not the "choke point" and I've dyno tested the k&n, stock air box with the "cut lid" which is super easy to do and there wasn't any difference.


porting on the other hand and exhaust mods offer quite a bit


demps just "updated" the old lsv 390 porting and I learned I had 1 birmal and 1 duns head as many of the later cars do.


I'll post up some pics of the heads, they look oh so sweet


the borla exhaust has some aggressive neck down at the resonator so an x pipe will really help


porting, tuning, displacement, and freeing up the exhaust will provide much better gains as mentioned.

[Norwegianmopar]

As always, many good advices and experiences shared in this group. Looks like I must concentrate on upgrading behind the air filter box, not in front of. Good thing is we can just pop a question in here, and there is always someone who knows and/or have tried it. You're the best guys, thanks [emoji108]

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[rkreigh]

the coplon duct seemed to have the best plenum volume and a good area "over the radiator" where the restriction is (it's not the filter)


make sure your accordion from the air cleaner doesn't collapse, they get old and soft rather than hard !!!


I like the samco and mitsu hoses. much better and no accordion to turbulate the air lots of inserts there do the same thing (a coffee can works in a pinch)


glad to see you enjoying the Zed R across the pond. we're here to help and maximize that enjoyment!