LT4 plus K&N filter = no change
Thread Starter
Race Director
Joined: Oct 2002
Posts: 10,864
Likes: 198
From: Southern CA
LT4 plus K&N filter = no change
I finally got around to putting in the K&N (about $75. I think). No cut lid, just replaced the stock paper element. My SOP evaluation is no change.
I have put K&N in several other vehicles & usually felt that it helped the intake breath a little better.
My theory is that the stock paper filter on the LT4 is so big (I don't know about l98's or lt1's - may be different) that it doesn't matter. If there is a restriction/gain to be made - it's elsewhere in the intake / exhaust stream.
I'm thinking the exhaust will be next.
Just doing the basic stuff here, not ready to tear the engine apart yet.
I have put K&N in several other vehicles & usually felt that it helped the intake breath a little better.
My theory is that the stock paper filter on the LT4 is so big (I don't know about l98's or lt1's - may be different) that it doesn't matter. If there is a restriction/gain to be made - it's elsewhere in the intake / exhaust stream.
I'm thinking the exhaust will be next.
Just doing the basic stuff here, not ready to tear the engine apart yet.
Melting Slicks
Joined: Dec 2001
Posts: 2,049
Likes: 0
From: Texas
Re: LT4 plus K&N filter = no change (froggy47)
I wouldn't expect much of a change anyway. I think what helped my LT1 the most was getting rid of all that damn metal on top of the filter. Can't get any more air in if it's being blocked. Cut your lid, you'll HEAR the thing breathe better! And $75? Ouch! I cut my lid for free, and just so happened to find a K&N filter underneath from the previous owner.
:cheers:
:cheers:
Thread Starter
Race Director
Joined: Oct 2002
Posts: 10,864
Likes: 198
From: Southern CA
Re: LT4 plus K&N filter = no change (BowTieBlood)
Yeah, that's what they are charging for em. The louvers on the lid are so wide open, I really don't seem them restricting. If I can pick up an old lid cheap maybe I'll try it.
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
Re: LT4 plus K&N filter = no change (froggy47)
I cut out the area around the louvers, before I went to the SLP triple snorkle. The only place air can get in is thru the louvers so it is restrictive to some extent.
It seems to me changing the element to K&N on a near stock engine has never been promoted as anything more that about a 1hp gain over a clean oem filter, certainly not seat of the pants gain. Same is true with opening the lid around the louvers. Only expect minor gains, maybe another 2-3 hp.
But every little bit helps and adds up. Removing the metal around the louvers is easy to do & free except for some time & maybe a litte touchup paint.
It seems to me changing the element to K&N on a near stock engine has never been promoted as anything more that about a 1hp gain over a clean oem filter, certainly not seat of the pants gain. Same is true with opening the lid around the louvers. Only expect minor gains, maybe another 2-3 hp.
But every little bit helps and adds up. Removing the metal around the louvers is easy to do & free except for some time & maybe a litte touchup paint.
Race Director
Joined: Nov 1999
Posts: 14,577
Likes: 0
From: Michigan in the summer, Florida the rest of the time
St. Jude Donor '08-'09-'11
Re: LT4 plus K&N filter = no change (froggy47)
A couple of years ago I installed a new K&N and cut lid, just before heading down to Bowling Green where I put the GS on a dyno.
After the second pull, the dyno operator looked down at the K&N and asked me if it was brand new. When he heard it was, he suggested pulling it for the final pull.
The last pull jumped up 8 HP! :eek: The dyno guy says he sees it all the time. According to him, K&N ships the filters with waaaay too much oil, needlessly impeding air flow. He suggests cleaning the filter and re-oiling as lightly as possible.
Brad
After the second pull, the dyno operator looked down at the K&N and asked me if it was brand new. When he heard it was, he suggested pulling it for the final pull.
The last pull jumped up 8 HP! :eek: The dyno guy says he sees it all the time. According to him, K&N ships the filters with waaaay too much oil, needlessly impeding air flow. He suggests cleaning the filter and re-oiling as lightly as possible.
Brad
Elite Torch Red Member
Joined: Sep 1999
Posts: 57,805
Likes: 23
From: Exit 89 GSP,Lakewood,NJ The Land Of Mojo
Cental/South NJ Events Coordinator
CI 1-2-3-4-5-6-7-8-9-10-11-12 Vet
CI-II Burnout & Drag Champ
St. Jude Donor '03-'04-'05-'06-'07
Re: LT4 plus K&N filter = no change (froggy47)
I can tell you from experience that a cut lid and K&N will yield no gain in the 1/4 mile.
I have a couple hundred runs to back it up.
I have a couple hundred runs to back it up.
Melting Slicks
Joined: Mar 2003
Posts: 2,472
Likes: 0
From: Toronto ONTARIO
Re: LT4 plus K&N filter = no change (Mr Mojo)
I can tell you from experience that a cut lid and K&N will yield no gain in the 1/4 mile.
I have a couple hundred runs to back it up.
I have a couple hundred runs to back it up.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Melting Slicks
Joined: Jan 2002
Posts: 2,784
Likes: 3
From: Atlanta GA
Re: LT4 plus K&N filter = no change (DieL)
After getting my LT4 i was giving it a once over, and decided to see how the Air fIlter was holding up.... Looking at the airbox, it was completely different then my 91. It stinks if you ask me... What the point of the metal sheet covering it. Oh well.... I pulled it off and to my liking I found a K&N.
But I dont like the intake setup on it, Seems incredably restrictive to me. The "Air bridge" as it goes over the radiator gets so thin. Between that and the Metal cover over the Box, I think some power could be picked up from changing over to aftermarket setup.
Is it worth $300 bucks though..... Prolly not, Ill end up buying a stock airbox and chop that up and see how it goes.... On the 91 Vette I cut it without thinking, but this one.... Ill just buy anotherone and keep the stock one in the garage
But I dont like the intake setup on it, Seems incredably restrictive to me. The "Air bridge" as it goes over the radiator gets so thin. Between that and the Metal cover over the Box, I think some power could be picked up from changing over to aftermarket setup.
Is it worth $300 bucks though..... Prolly not, Ill end up buying a stock airbox and chop that up and see how it goes.... On the 91 Vette I cut it without thinking, but this one.... Ill just buy anotherone and keep the stock one in the garage
Drifting
Joined: Mar 1999
Posts: 1,250
Likes: 1
From: Greensboro NC
Re: LT4 plus K&N filter = no change (StealDads67)
This is the oldest myth on the C4 forum. Cut lid and K&N will gain you absolutely 0 (read zero) hp.
We dynoed K&Ns against OEM and FRAM airfilters in1998 on LS1.com and the FRAM was right up there with the K&N in hp ... no difference at all. The OEM filters held back about 1 to 1.5 hp. Worst was a K&N after being cleaneed and re-oiled by the owner.....prolly with a little too much oil, which is easy to do.......it zapped over 5hp from the dynorun.
In my opinion the K&N plus open lid is an absolute waste of money and time, plus you expose your airfilter to water when you cut the lid.
Ohh, BTW ...we also measured the SLP "Claw" intake with its three round K&N...their filter surface is absolutely identical to the OEM panel filter.
I just can't see how this huge LT1/4 air filter panel is going to be restrictive when the C5 guys and the LS1 f-body guys get upwards of 400 hp (LS6) with a filter element half (!) the size of the LT1/4 C4 element.
[Modified by Alex D, 11:31 PM 9/1/2003]
We dynoed K&Ns against OEM and FRAM airfilters in1998 on LS1.com and the FRAM was right up there with the K&N in hp ... no difference at all. The OEM filters held back about 1 to 1.5 hp. Worst was a K&N after being cleaneed and re-oiled by the owner.....prolly with a little too much oil, which is easy to do.......it zapped over 5hp from the dynorun.
In my opinion the K&N plus open lid is an absolute waste of money and time, plus you expose your airfilter to water when you cut the lid.
Ohh, BTW ...we also measured the SLP "Claw" intake with its three round K&N...their filter surface is absolutely identical to the OEM panel filter.
I just can't see how this huge LT1/4 air filter panel is going to be restrictive when the C5 guys and the LS1 f-body guys get upwards of 400 hp (LS6) with a filter element half (!) the size of the LT1/4 C4 element.
[Modified by Alex D, 11:31 PM 9/1/2003]
Thread Starter
Race Director
Joined: Oct 2002
Posts: 10,864
Likes: 198
From: Southern CA
Re: LT4 plus K&N filter = no change (StealDads67)
I hear you on that plastic "air box funnel" getting thin. I was wondering if it could partially collapse during wot? I can see that mine has got some warpage from heat or whatever? The K&N came with some "weatherstripping" to get a tight seal around the edges. It is a BIG air filter though.
