engine upgrade help - CorvetteForum - Chevrolet Corvette Forum Discussion

Notices
C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette

engine upgrade help

Old 09-23-2018, 06:33 AM
  #1  
Primož Krajcar
CF Senior Member
Thread Starter
 
Member Since: Jul 2012
Location: Slovenia, EU
Posts: 612
Thanked 46 Times in 33 Posts
2017 C3 of Year Finalist
Default engine upgrade help

I'm currently running Edelbrock Performer intake on my 71 with L48 engine.
I'm thinking of going EFI way with sniper EFI.
I was looking at Edelbrock 7501 Performer RPM air-gap and Blueprint H8002K heads when doing this.
Was also looking at camshaft change but that is hard to choose as there are soo many. The closest I got was Howards 111145-12 but tech support suggested CL113215-10.
Otherwise the engine is stock.
Do I have to change the intake to run Sniper or is spreadbore intake OK?
Is anybody running upgraded engine with stock TH400, that includes converter, with EFI?
Primož Krajcar is offline  
Old 09-23-2018, 01:39 PM
  #2  
Strokemyaxe
CF Senior Member
 
Strokemyaxe's Avatar
 
Member Since: Jul 2014
Location: Arlington TX
Posts: 582
Thanked 24 Times in 23 Posts
Default

Spread bore/Square bore is no different to the EFI as long as your intake is dual drilled (which I believe yours is) for the Square bore bolt pattern. The real question you should be asking is Dual Plane or Single Plane for the Holley Sniper? There are known metering issues running a dual plane intake with that EFI system. Single plane intakes allow all runners to share all injectors, allowing the sniper to to operate more efficiently.

Choose your heads first and wisely. Cams come and go, but heads are usually there to stay. Be realistic about what you want out of the engine and understand the limitations of the stock internals.
Strokemyaxe is online now  
The Following User Says Thank You to Strokemyaxe For This Useful Post:
Primož Krajcar (09-23-2018)
Old 09-23-2018, 03:02 PM
  #3  
Primož Krajcar
CF Senior Member
Thread Starter
 
Member Since: Jul 2012
Location: Slovenia, EU
Posts: 612
Thanked 46 Times in 33 Posts
2017 C3 of Year Finalist
Default

Well air gap intake has that small plenum divider cut so shouldn't be an issue!
Primož Krajcar is offline  
Old 09-23-2018, 05:25 PM
  #4  
60 SHARK
CF Senior Member
 
Member Since: Aug 2016
Location: CLEVELAND STUCK IN OHIO
Posts: 240
Thanked 33 Times in 27 Posts
Default

I'm thinking,, if you already have the air gap intake, ok, use it,,, if your going to purchase a new intake, don't get the air gap,,,,, EFI will be happier with single plane style,,,,,just my $.02,,
60 SHARK is offline  
Old 09-23-2018, 06:34 PM
  #5  
Strokemyaxe
CF Senior Member
 
Strokemyaxe's Avatar
 
Member Since: Jul 2014
Location: Arlington TX
Posts: 582
Thanked 24 Times in 23 Posts
Default

Originally Posted by Primož Krajcar View Post
Well air gap intake has that small plenum divider cut so shouldn't be an issue!
Im not sure that gap would be enough to equalize the mixture. Go single plane if you go EFI.*

-Stroke
Strokemyaxe is online now  
Old 09-23-2018, 11:23 PM
  #6  
Primož Krajcar
CF Senior Member
Thread Starter
 
Member Since: Jul 2012
Location: Slovenia, EU
Posts: 612
Thanked 46 Times in 33 Posts
2017 C3 of Year Finalist
Default

Well then it is a Torker II manifold for me or Weiand team g.
Primož Krajcar is offline  
Old 09-25-2018, 03:18 AM
  #7  
Stingre'
CF Senior Member
 
Stingre''s Avatar
 
Member Since: Mar 2017
Location: Torrance Ca
Posts: 136
Thanked 11 Times in 11 Posts
Default Performer RPM


Performer RPM with Dart heads, ZZ9 Cam. Perfect combo, 450hp
Stingre' is offline  
The Following User Says Thank You to Stingre' For This Useful Post:
Primož Krajcar (09-25-2018)
Old 09-25-2018, 05:48 AM
  #8  
terrys6t8roadster
CF Senior Member
 
terrys6t8roadster's Avatar
 
Member Since: May 2012
Location: Allenton Wisconsin
Posts: 1,666
Thanked 156 Times in 153 Posts
Default

Was running a 2101 and a spreadbore before switching to the Sniper EFI, but wanted a square bore manifold. Went with the EPS manifold then read articles about dual versus single plane with EFI, so the new manifold was modified. Been running excellent all summer. T
terrys6t8roadster is offline  
The Following User Says Thank You to terrys6t8roadster For This Useful Post:
Primož Krajcar (09-25-2018)
Old 09-25-2018, 01:28 PM
  #9  
Primož Krajcar
CF Senior Member
Thread Starter
 
Member Since: Jul 2012
Location: Slovenia, EU
Posts: 612
Thanked 46 Times in 33 Posts
2017 C3 of Year Finalist
Default

Originally Posted by Stingre' View Post
Performer RPM with Dart heads, ZZ9 Cam. Perfect combo, 450hp
Interesting. I checked, Performer RPM and RPM air-gap have the same intake manifold height.
I thought that air-gap is higher due to the design.
Both have same rpm range 1500 - 6500 rpm.
Primož Krajcar is offline  
Old 09-25-2018, 01:44 PM
  #10  
NewbVetteGuy
CF Senior Member
 
NewbVetteGuy's Avatar
 
Member Since: Jun 2016
Location: Woodinville WA
Posts: 2,115
Thanked 160 Times in 141 Posts
Default

Originally Posted by Primož Krajcar View Post
Interesting. I checked, Performer RPM and RPM air-gap have the same intake manifold height.
I thought that air-gap is higher due to the design.
Both have same rpm range 1500 - 6500 rpm.
Are you sure about that??* There were some very long C3 intake height and hood height threads and the consensus*was that the Performer RPM and Performer Air Gap (non RPM) would both clear the later C3 hoods, but the combination of RPM+Air Gap's increased height made hood clearance a real problem in a C3 stock hood.* -If there IS a height issue with RPM+AIR Gap get the Air Gap and just cut down the divider.* The colder air is what you want and cold start won't be an issue with EFI.

I like Terry's solution. Intake wave tuning is intake wave tuning; there's no getting around it; the longer runners with a dual plane intake is going to prop up the low and mid-RPM torque curve; why lose it? The air / fuel distribution issues of a dual plane are there with a carburetor*why is it so much of a bigger deal all of a sudden when it's a computer dumping the fuel into the venturi's rather than a dumb carb??!?


Adam
NewbVetteGuy is offline  
Old 09-25-2018, 01:51 PM
  #11  
Primož Krajcar
CF Senior Member
Thread Starter
 
Member Since: Jul 2012
Location: Slovenia, EU
Posts: 612
Thanked 46 Times in 33 Posts
2017 C3 of Year Finalist
Default

Originally Posted by NewbVetteGuy View Post
Are you sure about that??* There were some very long C3 intake height and hood height threads and the consensus*was that the Performer RPM and Performer Air Gap (non RPM) would both clear the later C3 hoods, but the combination of RPM+Air Gap's increased height made hood clearance a real problem in a C3 stock hood.* -If there IS a height issue with RPM+AIR Gap get the Air Gap and just cut down the divider.* The colder air is what you want and cold start won't be an issue with EFI.

I like Terry's solution. Intake wave tuning is intake wave tuning; there's no getting around it; the longer runners with a dual plane intake is going to prop up the low and mid-RPM torque curve; why lose it? The air / fuel distribution issues of a dual plane are there with a carburetor*why is it so much of a bigger deal all of a sudden when it's a computer dumping the fuel into the venturi's rather than a dumb carb??!?


Adam
Yes both are 4.720 in high! According to Summit and according to Edelbrock websites!
Primož Krajcar is offline  
Old 09-25-2018, 02:27 PM
  #12  
Primož Krajcar
CF Senior Member
Thread Starter
 
Member Since: Jul 2012
Location: Slovenia, EU
Posts: 612
Thanked 46 Times in 33 Posts
2017 C3 of Year Finalist
Default

Interesting comparison of the intakes from Hot Rod website from 5 years ago


Primož Krajcar is offline  
Old 09-26-2018, 05:14 AM
  #13  
terrys6t8roadster
CF Senior Member
 
terrys6t8roadster's Avatar
 
Member Since: May 2012
Location: Allenton Wisconsin
Posts: 1,666
Thanked 156 Times in 153 Posts
Default

One of those Weiand manifolds might be a single plane and by all reports an excellent manifold. T
terrys6t8roadster is offline  
Old 09-26-2018, 10:29 AM
  #14  
NewbVetteGuy
CF Senior Member
 
NewbVetteGuy's Avatar
 
Member Since: Jun 2016
Location: Woodinville WA
Posts: 2,115
Thanked 160 Times in 141 Posts
Default

Originally Posted by Primož Krajcar View Post
Interesting comparison of the intakes from Hot Rod website from 5 years ago


Its a real shame they didnt show torque @1,500 rpm - 2,000 rpm. *Stock C3 TC stall speeds were 1,650 for L48; 1,800 for L82.


Adam
NewbVetteGuy is offline  
Old 09-26-2018, 10:32 AM
  #15  
NewbVetteGuy
CF Senior Member
 
NewbVetteGuy's Avatar
 
Member Since: Jun 2016
Location: Woodinville WA
Posts: 2,115
Thanked 160 Times in 141 Posts
Default

Originally Posted by terrys6t8roadster View Post
One of those Weiand manifolds might be a single plane and by all reports an excellent manifold. T
If this is the intake shootout series, I think they had separate articles for the dual planes and the single planes; the Street Warrior Weiands were on my short list back when I was going to run a dual plane and I was only looking at dual planes so I think theyre dual planes.
NewbVetteGuy is offline  
Old 09-26-2018, 10:41 AM
  #16  
cuisinartvette
CF Senior Member
 
Member Since: Oct 2004
Location: Valencia Ca.
Posts: 66,420
Thanked 946 Times in 873 Posts
St. Jude Donor '05
Default

youll go past that 1-2k mark so quick not sure it matters they will all do well off the line.
cuisinartvette is offline  
Old 09-26-2018, 01:36 PM
  #17  
Primož Krajcar
CF Senior Member
Thread Starter
 
Member Since: Jul 2012
Location: Slovenia, EU
Posts: 612
Thanked 46 Times in 33 Posts
2017 C3 of Year Finalist
Default

Here is the link to the full article:
https://www.hotrod.com/articles/dual...d-comparisons/

I can't find part 1 though!
Primož Krajcar is offline  
Old 09-26-2018, 02:44 PM
  #18  
NewbVetteGuy
CF Senior Member
 
NewbVetteGuy's Avatar
 
Member Since: Jun 2016
Location: Woodinville WA
Posts: 2,115
Thanked 160 Times in 141 Posts
Default

Originally Posted by Primož Krajcar View Post
Here is the link to the full article:
https://www.hotrod.com/articles/dual...d-comparisons/

I can't find part 1 though!

https://www.hotrod.com/articles/19-s...-intakes-test/


Adam
NewbVetteGuy is offline  
The Following User Says Thank You to NewbVetteGuy For This Useful Post:
Primož Krajcar (09-26-2018)


Thread Tools
Search this Thread
Sponsored Ads
Vendor Directory

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 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: