Notices
C4 General Discussion General C4 Corvette Discussion not covered in Tech

Why remove A.I.R. pump?

 
Old 06-02-2019, 05:09 PM
  #1  
Topcat7
Junior Member
Thread Starter
 
Topcat7's Avatar
 
Member Since: Sep 2018
Posts: 32
Received 0 Likes on 0 Posts
Default Why remove A.I.R. pump?

I am tossing up whether or not to remove the A.I.R. pump from my '89 L98 Corvette.
I am told that by doing so I can expect an increase of between 20-30HP. Is this so?

I am also told that there is a 'restrictor' in the air intake system that was put there to 'de-tune' the engine,
and if you remove that 'restrictor' you can make significant gains in HP by improving the air-flow. Is this true?
Topcat7 is offline  
Old 06-02-2019, 06:27 PM
  #2  
Red86Z51
CF Senior Member
 
Red86Z51's Avatar
 
Member Since: Mar 2003
Location: Indianapolis IN
Posts: 2,444
Received 144 Likes on 114 Posts
Default

Originally Posted by Topcat7 View Post
I am tossing up whether or not to remove the A.I.R. pump from my '89 L98 Corvette.
I am told that by doing so I can expect an increase of between 20-30HP. Is this so?

I am also told that there is a 'restrictor' in the air intake system that was put there to 'de-tune' the engine,
and if you remove that 'restrictor' you can make significant gains in HP by improving the air-flow. Is this true?
You were told incorrectly regarding hp gain by removal of the air pump...the short answer is no.
Red86Z51 is offline  
Old 06-02-2019, 08:44 PM
  #3  
Joe C
CF Senior Member
 
Member Since: Aug 2000
Posts: 10,891
Received 530 Likes on 461 Posts
Default

you would be lucky to see 2-3 hp. definitely nothing by the SOTP. removing those things seems like more trouble than it's worth.
Joe C is offline  
The following users liked this post:
Mity2 (06-04-2019)
Old 06-02-2019, 08:49 PM
  #4  
Topcat7
Junior Member
Thread Starter
 
Topcat7's Avatar
 
Member Since: Sep 2018
Posts: 32
Received 0 Likes on 0 Posts
Default

Thanks @Red86Z51 and @Joe_C . If that is the only gain, it is not worth the cost.

Does anyone know about the 'restrictor'?
Topcat7 is offline  
Old 06-02-2019, 09:10 PM
  #5  
Joe C
CF Senior Member
 
Member Since: Aug 2000
Posts: 10,891
Received 530 Likes on 461 Posts
Default

Originally Posted by Topcat7 View Post
Thanks @Red86Z51 and @Joe_C . If that is the only gain, it is not worth the cost.

Does anyone know about the 'restrictor'?
been into C4's for about 25 years now, and can't recall anything about a restrictor. the air intake is somewhat restrictive, and there not much that can be done with stock components. gasket match, a little pocket porting, and long tubes is about all you can do to a stock system. L98's are L98's - more torque than horsepower.

Last edited by Joe C; 06-02-2019 at 09:11 PM.
Joe C is offline  
Old 06-03-2019, 05:48 AM
  #6  
Red86Z51
CF Senior Member
 
Red86Z51's Avatar
 
Member Since: Mar 2003
Location: Indianapolis IN
Posts: 2,444
Received 144 Likes on 114 Posts
Default

Originally Posted by Joe C View Post
been into C4's for about 25 years now, and can't recall anything about a restrictor. the air intake is somewhat restrictive, and there not much that can be done with stock components. gasket match, a little pocket porting, and long tubes is about all you can do to a stock system. L98's are L98's - more torque than horsepower.


The ONLY restrictor I've ever known of in the L98's is the restrictor in the rear coolant passage of the intake manifold... that's there to keep coolant at the rear of the engine a little longer. Removing that would do nothing for your engine's performance...removing that simply allows you to remove that small bypass hose that runs to the coolant return line from the heater core.
Red86Z51 is offline  
Old 06-03-2019, 11:08 AM
  #7  
Tom400CFI
CF Senior Member
 
Tom400CFI's Avatar
 
Member Since: Aug 2004
Location: Park City Utah
Posts: 14,475
Received 676 Likes on 592 Posts
Default

Originally Posted by Joe C View Post
can't recall anything about a restrictor.
Originally Posted by Red86Z51 View Post


The ONLY restrictor I've ever known of in the L98's is the restrictor in the rear coolant passage of the intake manifold... that's there to keep coolant at the rear of the engine a little longer. Removing that would do nothing for your engine's performance...removing that simply allows you to remove that small bypass hose that runs to the coolant return line from the heater core.
X3.

The only "restrictor" that I'm aware of is the entire TPI system.
Tom400CFI is offline  
Old 06-03-2019, 11:18 AM
  #8  
Paul Workman
CF Senior Member
 
Paul Workman's Avatar
 
Member Since: Oct 2004
Location: "Below I-80" Illinois
Posts: 5,636
Received 223 Likes on 204 Posts
Default

Originally Posted by Topcat7 View Post
I am tossing up whether or not to remove the A.I.R. pump from my '89 L98 Corvette.
I am told that by doing so I can expect an increase of between 20-30HP. Is this so?
As mentioned, there's little if any meaningful performance increase as result of removing the A.I.R. pump. However, removing the pump can negatively affect the efficiency of the cats - especially on start up, not to mention having to pass the smog station inspection of factory emissions equipment!
Originally Posted by Topcat7 View Post
am also told that there is a 'restrictor' in the air intake system that was put there to 'de-tune' the engine,
and if you remove that 'restrictor' you can make significant gains in HP by improving the air-flow. Is this true?
Restrictor plates apply to certain racing rules (NASCAR, etc) intended for "normalizing" horsepower of all competitors. Such restrctors in reference to the standard (i.e., street driven) cars is pure internet BS.

Last edited by Paul Workman; 06-03-2019 at 11:19 AM.
Paul Workman is offline  
Old 06-03-2019, 01:23 PM
  #9  
belairbrian
CF Senior Member
 
belairbrian's Avatar
 
Member Since: Oct 2016
Location: Central Alabama
Posts: 1,432
Received 187 Likes on 162 Posts
Default

My 92 had the restrictor, but I got tired of hearing "slow your a$$ down", so I removed her it..
belairbrian is offline  
The following 6 users liked this post by belairbrian:
Blackcorvette_85 (06-04-2019), DGXR (06-04-2019), FOURSPEEDVETTE (06-04-2019), Joe C (06-05-2019), rblakeney (06-04-2019), vette196 (06-03-2019)
Old 06-03-2019, 01:29 PM
  #10  
pologreen1
CF Senior Member
 
pologreen1's Avatar
 
Member Since: Dec 2007
Posts: 16,117
Received 222 Likes on 212 Posts
Default

While you are at it...

All smog items, ac, and heat, radio, speakers, frisbee, spare tire, cruise control, stock exhaust, etc. The car will feel a lot better. j/k.

The car is a detuned 350, that is done with emissions, excessively restrictive intake, exhaust, heads, small cam, ECU,

A good running / breathing "hypo" 350 on pump gas is capable of 425ish chp. Basically you heard right. It is choked.

LT1 intake
Heads
Cam (if auto need stall / gears)
Headers/ exhaust
1.6rr's
24+lb injectors
Tune

So that recipe will get you some where around 425ish chp. Pricey though!!!

Last edited by pologreen1; 06-03-2019 at 01:32 PM.
pologreen1 is offline  
Old 06-03-2019, 03:26 PM
  #11  
aklim
CF Senior Member
 
aklim's Avatar
 
Member Since: Jul 2004
Location: Hartford WI
Posts: 16,118
Received 822 Likes on 803 Posts
Default

Originally Posted by Paul Workman View Post
As mentioned, there's little if any meaningful performance increase as result of removing the A.I.R. pump. However, removing the pump can negatively affect the efficiency of the cats - especially on start up, not to mention having to pass the smog station inspection of factory emissions equipment!
But if he has no emissions to pass, it should be fine. More room to work around in the engine bay is a good thing. Does smog testing do a cold start up test?
aklim is offline  
Old 06-03-2019, 03:51 PM
  #12  
Tom400CFI
CF Senior Member
 
Tom400CFI's Avatar
 
Member Since: Aug 2004
Location: Park City Utah
Posts: 14,475
Received 676 Likes on 592 Posts
Default

No. Can't test anything until it goes into closed loop.
Tom400CFI is offline  
Old 06-03-2019, 06:52 PM
  #13  
LWesthaver
CF Senior Member
 
LWesthaver's Avatar
 
Member Since: Dec 1999
Location: Columbia MD
Posts: 806
Received 54 Likes on 35 Posts
Default

I removed my A.I.R. pump and I noticed that the engine compartment was a lot quieter when the engine is running. I never realized that the pump made so much noise.

But the main advantage is having more access to the front of the engine. The water pump in particular. There's a lot less clutter on the front of the engine now. And you loose about 15 pounds of hardware and plumbing.

-Wes
LWesthaver is offline  
The following users liked this post:
vettespecial (06-15-2019)
Old 06-03-2019, 06:54 PM
  #14  
aklim
CF Senior Member
 
aklim's Avatar
 
Member Since: Jul 2004
Location: Hartford WI
Posts: 16,118
Received 822 Likes on 803 Posts
Default

Originally Posted by LWesthaver View Post
I removed my A.I.R. pump and I noticed that the engine compartment was a lot quieter when the engine is running. I never realized that the pump made so much noise.

But the main advantage is having more access to the front of the engine. The water pump in particular. There's a lot less clutter on the front of the engine now. And you loose about 15 pounds of hardware and plumbing.

-Wes
Was your pump broken or not working well? Mine was and it did not make it much difference, noise wise.
aklim is offline  
Old 06-04-2019, 04:55 PM
  #15  
85WHITEZ51
CF Senior Member
 
85WHITEZ51's Avatar
 
Member Since: Dec 2000
Location: Leander TX
Posts: 1,472
Received 11 Likes on 11 Posts
Default

The only other benefit I'm aware of that hasn't been mentioned yet is it gets it away from from your alternator a bit. I've recently done this mod for this reason as I'm getting tired of fried alternators, but since I just recently did this I can't personally confirm it helps but it did move it away from my headers.
85WHITEZ51 is offline  
Old 06-04-2019, 05:18 PM
  #16  
Topcat7
Junior Member
Thread Starter
 
Topcat7's Avatar
 
Member Since: Sep 2018
Posts: 32
Received 0 Likes on 0 Posts
Default

Thanks, Guys. From what you have said, I have decided to leave the A.I.R. pump where it is, (at least until I decide to install headers).

As far as the 'restrictor' goes, if there is not one to remove, then I cannot remove it.

Actually the car performs better than any car in my (small) collection as it is, so I think that I will just be happy driving her as she is.

Thanks, again.
Topcat7 is offline  
Old 06-04-2019, 06:20 PM
  #17  
aklim
CF Senior Member
 
aklim's Avatar
 
Member Since: Jul 2004
Location: Hartford WI
Posts: 16,118
Received 822 Likes on 803 Posts
Default

Originally Posted by 85WHITEZ51 View Post
The only other benefit I'm aware of that hasn't been mentioned yet is it gets it away from from your alternator a bit. I've recently done this mod for this reason as I'm getting tired of fried alternators, but since I just recently did this I can't personally confirm it helps but it did move it away from my headers.
What has the AIR pump got to do with the alternator? It doesn't even get that hot.
aklim is offline  
Old 06-04-2019, 06:22 PM
  #18  
aklim
CF Senior Member
 
aklim's Avatar
 
Member Since: Jul 2004
Location: Hartford WI
Posts: 16,118
Received 822 Likes on 803 Posts
Default

Originally Posted by Topcat7 View Post
Thanks, Guys. From what you have said, I have decided to leave the A.I.R. pump where it is, (at least until I decide to install headers).

As far as the 'restrictor' goes, if there is not one to remove, then I cannot remove it.

Actually the car performs better than any car in my (small) collection as it is, so I think that I will just be happy driving her as she is.

Thanks, again.
At which point, you can run a pulley to delete it.

Of course there is. Intake. Tune and headers with intake would be great
aklim is offline  
Old 06-04-2019, 11:42 PM
  #19  
LWesthaver
CF Senior Member
 
LWesthaver's Avatar
 
Member Since: Dec 1999
Location: Columbia MD
Posts: 806
Received 54 Likes on 35 Posts
Default

Originally Posted by aklim View Post
Was your pump broken or not working well? Mine was and it did not make it much difference, noise wise.
My smog pump was making (what I believe was) bearing noise. I never noticed the noise until it was gone.
LWesthaver is offline  
Old 06-04-2019, 11:54 PM
  #20  
aklim
CF Senior Member
 
aklim's Avatar
 
Member Since: Jul 2004
Location: Hartford WI
Posts: 16,118
Received 822 Likes on 803 Posts
Default

Originally Posted by LWesthaver View Post
My smog pump was making (what I believe was) bearing noise. I never noticed the noise until it was gone.
Ah. Like I was saying, but in a clumsy manner, my pump was ok and I didn't notice much sound change after I took it out. It did spin freely.
aklim is offline  

Thread Tools
Search this Thread

Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: