Intake Manifold Choice

[Orange65]

I am currently building a 489 BBC that I plan on using street/strip. The intent is 600-650 HP NA with a 6500-7000 RPM rev limit. I have two intake manifolds that I can use. One is a Dart single plane intake that has had injector bungs installed in it. It was previously used on a 555 with a turbo. It has a flange for a dominator. The other is an Edelbrock TM2R single plane that I am converting to EFI. It is a 4150 flange. The Dart intake has a much bigger plenum volume and runners compared to the TM2R.

How does plenum volume affect an EFI engine and which intake would you use?

[Matt Cramer]

As a general rule, carbed intakes will have pretty similar characteristics with EFI, with the exception that if low RPM issues are due to fuel distribution problems these are likely to become less significant (which is why Holley had reworked a Weiand tunnel ram for EFI and ended up with a fairly streetable intake). Larger runners and plenum would work better for feeding a big inch high horsepower motor but may make for slightly less throttle response - slightly. I think the Dart intake is likely to be a bit better for your motor.

[TC]

IMO I'd sell both those intakes and go with an Edelbrock Victor Jr with the EFI bosses already machined in it, you don't have the cubes or are spinning the RPM to warrant a dominator intake, it's just going to cost you power.......This is the manifold I would run with what you want to do.....

http://www.summitracing.com/parts/EDL-29025/

[JeffMcKC]

I would find a air gap, if I ran a single plane, I would get a Old Holly Strip Dominator off ebay, and EFI it. The Darts not a great intake.

Air is air nothing has changed about that, the only difference is there will be no Carb signal needed, its still all about plenum size and runner lenghts with port entry while having the correct air speeds.

[BBR]

I say use the Dart. A near 500" motor spinning 6.5-7k is going to want all the air it can get.

[Orange65]

I would find a air gap, if I ran a single plane, I would get a Old Holly Strip Dominator off ebay, and EFI it. The Darts not a great intake.

Air is air nothing has changed about that, the only difference is there will be no Carb signal needed, its still all about plenum size and runner lenghts with port entry while having the correct air speeds.

Are you referring to an Edelbrock RPM Air Gap? I have one of those that I am trying to sell. I did not think it would be preferable to the single plane design of the TM2R or the Dart.

[JeffMcKC]

The Dart is over rated out of the box.......
489 peaking at 6300 or earlier to shift at 6500/7000 is not a huge amount of air.
TM2R is to small a plenum and runner and way behind in the others.

Single I would work on a Holley Strip Dominator with a adaptor and open it up as My first choice to EFI.

Second choice of a single would be a Super Victor it would be first but the Holley will work as good and cheaper of ebay

I think the RPM Air Gap with some Clean up would work very good too.


Unlike TCs comment, the EFI wont really care about the size of the throttle body as long as its not a restriction, its all about runners and plenum as the restriction, no carb signal gets used

[BKBridges]

Are you referring to an Edelbrock RPM Air Gap? I have one of those that I am trying to sell. I did not think it would be preferable to the single plane design of the TM2R or the Dart.

Im not sure where the "single plane is the intake of choice for MPFI" thoughts came from, but just like pressurization, if the manifold works well N/A, it will work well/better with MPFI. The super low deck, low tech, dual plane C-65 manifold from Edelbrock made 600hp @ 6000rpm with MPFI after we worked it over, heres the article: http://www.vetteweb.com/tech/vemp_11...t/viewall.html We picked that manifold due to severe hood clearance issues. After we did our normal porting, Tony Mamo ported the wee out of it.
Not saying that is the manifold/set-up for you, but its not a single plane.
We use the air gap dual plane for the SB Mopars preferrably over the M1 single plane MPI manifolds as they provide better power over the entire RPM range (just like with a Carburetor...) Find the best carb'ed manifold for your needs (RPM range, driving reqts. hood clearance) then MPFI it and it will be fine.
I kinda like the Hilborn crossram set-ups for the BBC.
BKB

[dieselgeek]

Every time I've been part of a dyno test where we're testing out-of-box intakes for MPFI, the single plane has *always* made more power from bottom to top. Maybe that's just me and my limited testing experience though.

[JeffMcKC]

Every time I've been part of a dyno test where we're testing out-of-box intakes for MPFI, the single plane has *always* made more power from bottom to top. Maybe that's just me and my limited testing experience though.

I am a "line of site" guy. I find the same even with Carbs Scott.

Everyone will say stay away from tunnel rams but they make TQ across the board a lot of times. Its about the runners, but if you already have a "Good Duel Plane" Your not going to make tons more with the single.

http://www.summitracing.com/parts/EDL-7562/ in this case not a bad choice if you have it already remember if he wants to shift between 6500 and 7000 then it needs peak power to be about 6300 so he goes past and drops back not to far down to stay in the meat of the power band for shift recovery

[BKBridges]

DG,
Dyno wise the single plane may make better numbers, but as you know its the area under the curve at the needed RPM that is the key to driveability. Single plane or dual, its all about how the air gets to the head... You can un-wind a dual plane and they look amazingly like a single plane on two different levels... Its a packaging thing as well as a way the Ford flathead engineers got around charge interference between cylinders...(no longer an issue with MPFI) But, since both single and dual plane manifolds have their place, (low rpm grunt (long runner)/ high rpm power (short runner)) I like to make manifolds that are "both" with progressive staging between the true dual plane system with long runners and the pseudo single plane with short runners...Yeah, its a six pack...good for all things street when done correctly...For WOT only (drag racing) a properly sized plenum on a single plane is about all you need. Not a big fan of Dominator pattern manifold openings unless your motor is 700+hp
BKB

[BKBridges]

DG,
Does anyone really make a dual plane MPFI manifold out of the box?
BKB

[dieselgeek]

DG,
Dyno wise the single plane may make better numbers, but as you know its the area under the curve at the needed RPM that is the key to driveability. Single plane or dual, its all about how the air gets to the head... You can un-wind a dual plane and they look amazingly like a single plane on two different levels... Its a packaging thing as well as a way the Ford flathead engineers got around charge interference between cylinders...(no longer an issue with MPFI) But, since both single and dual plane manifolds have their place, (low rpm grunt (long runner)/ high rpm power (short runner)) I like to make manifolds that are "both" with progressive staging between the true dual plane system with long runners and the pseudo single plane with short runners...Yeah, its a six pack...good for all things street when done correctly...For WOT only (drag racing) a properly sized plenum on a single plane is about all you need. Not a big fan of Dominator pattern manifold openings unless your motor is 700+hp
BKB

I hear ya, and I respect your work but... I'd put Jeff McKC's and CDMBill's "drivability" up against any OEM ride here. I attribute that largely to using an EMS that's NOT a "Bigstuff3/FAST/Gen7" - but one that allows much finer tuning at part throttle. Both their cars start up like a brand new Honda, leave the light at part throttle like a new Honda, but WOT run like raped apes.

[JeffMcKC]

As far as single planes it would be very hard to beat the Crazy VE of Doc's Maxi Ported Super Victor EFI. With great driveability and ease of start with his IAC motor.

[JeffMcKC]

DG,
Dyno wise the single plane may make better numbers, but as you know its the area under the curve at the needed RPM that is the key to driveability. Single plane or dual, its all about how the air gets to the head... You can un-wind a dual plane and they look amazingly like a single plane on two different levels... Its a packaging thing as well as a way the Ford flathead engineers got around charge interference between cylinders...(no longer an issue with MPFI) But, since both single and dual plane manifolds have their place, (low rpm grunt (long runner)/ high rpm power (short runner)) I like to make manifolds that are "both" with progressive staging between the true dual plane system with long runners and the pseudo single plane with short runners...Yeah, its a six pack...good for all things street when done correctly...For WOT only (drag racing) a properly sized plenum on a single plane is about all you need. Not a big fan of Dominator pattern manifold openings unless your motor is 700+hp
BKB

This would depend on what wave you trying to catch.

I would agree with the second with a Carb but not the EFI