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wow.. ok.. got me.. lets stick with that 80's thought and tech... lol
the runner speed and volume screws with the MAF sensor...when different lengths of runners like in a duel plain...
GM's initial experiments into this era, do not bode well with current tech.
do you run a aftermarket EFI?
We do, infect we have put on 3, one Edelbrock and 2 FAST...
please do tell your personal experience..
Spend some time on the FAST EFI sight... like I did for 3 years figuring out all the problems... then lets hear that...
Sorry,,, but you are flat out wrong...
if the OP still wishes to use a DP, after seeing what I copied and posted from the FAST sight of others with similar problems and there surprise of the power gain through out the RPM band, and overall running quality, fine...
but your info is incorrect and bad.
wow.. ok.. got me.. lets stick with that 80's thought and tech... lol
the runner speed and volume screws with the MAF sensor...when different lengths of runners like in a duel plain...
GM's initial experiments into this era, do not bode well with current tech.
do you run a aftermarket EFI?
We do, infect we have put on 3, one Edelbrock and 2 FAST...
please do tell your personal experience..
It's not my fault you can't tune as good as GM engineers.
In the early 90's with the very low hood coming out on the 93 camaro, GM developed the Gen 2 LT1 intake:
They originally did it as an interim solution to the 93 camaro's hood clearance, but discovered it was so easy to tune they kept it and put it in production, despite the poor midrange performance compared to the TPI intake. I had this intake and engine in my 96 impala ss. We were looking for an option that would give us more torque in the midrange, as the impala was a heavy *** car, and the Lingenfelter Super Ram was too damn expensive. So we had to look for alternatives.
Back in the late 90's, Accel made an elbow that would adapt the stock Gen 2 LT1 throttle body to GM's Performance Parts carb LT1 intake...
which was a standard Edelbrock Performer RPM intake modified for the LT1:
Maybe the intake elbow acted as a spacer, but we never had a single issue with that intake after we got it tuned and it pretty much bumped our torque curve by 30-40 ft/lbs across the entire rpm band.
I couldn't find a picture of the exact setup, but here's something similar. Plus, it shows injector bungs welded into a carb intake, which is what I was suggesting to the OP in the first place:
Maybe the OP can keep his excellent midrange and still run MPFI by using a similar elbow. Edelbrock and Holley both make an adapter elbow for the LS1 throttle body.
Last edited by sstonebreaker; 12-12-2018 at 03:55 PM.
It's not my fault you can't tune as good as GM engineers.
In the early 90's with the very low hood coming out on the 93 camaro, GM developed the Gen 2 LT1 intake:
They originally did it as an interim solution to the 93 camaro's hood clearance, but discovered it was so easy to tune they kept it and put it in production, despite the poor midrange performance compared to the TPI intake. I had this intake and engine in my 96 impala ss. We were looking for an option that would give us more torque in the midrange, as the impala was a heavy *** car, and the Lingenfelter Super Ram was too damn expensive. So we had to look for alternatives.
Back in the late 90's, Accel made an elbow that would adapt the stock Gen 2 LT1 throttle body to GM's Performance Parts carb LT1 intake...
which was a standard Edelbrock Performer RPM intake modified for the LT1:
Maybe the intake elbow acted as a spacer, but we never had a single issue with that intake after we got it tuned and it pretty much bumped our torque curve by 30-40 ft/lbs across the entire rpm band.
I couldn't find a picture of the exact setup, but here's something similar. Plus, it shows injector bungs welded into a carb intake, which is what I was suggesting to the OP in the first place:
Maybe the OP can keep his excellent midrange and still run MPFI by using a similar elbow. Edelbrock and Holley both make an adapter elbow for the LS1 throttle body.
back in the 80's and 90's they did a lot of stuff they don't do now....
I would not copy a 80's tech set up...
single plain is the way to go... A DP is not... and no, a DP will not help in any RPM range...
call FAST or Edelbrock, as I did, and they will both tell you only run a SP...
but YOU can run a DP if you want... just will hinder performance..
Again, how many aftermarket EFI's have you installed??
back in the 80's and 90's they did a lot of stuff they don't do now....
I would not copy a 80's tech set up...
single plain is the way to go... A DP is not... and no, a DP will not help in any RPM range...
call FAST or Edelbrock, as I did, and they will both tell you only run a SP...
but YOU can run a DP if you want... just will hinder performance..
Again, how many aftermarket EFI's have you installed??
You keep trying to say a dual plane (that's "plane", not "plain") hurts performance. Yet switching from the factory intake to the dual plane netted me half a second in the quarter, most of that coming from my 0-60 time. I went from 13.0 at 103 to 12.6 at 104 in identical density altitude conditions. (notice my mph didn't change even though my ET dropped? That's torque, baby.) So your statement that a dual plane hurts performance is bullshit. You just have to know what you're doing and what you're trying to achieve. I can't help it that you couldn't make it work.
The OP stated that he likes his car's performance now, but wants to switch to MPFI to get better mileage. He specifically stated he had reservations about single plane intakes losing low and midrange torque, particularly because his cam is optimized for performance below 6,000 rpm. I successfully installed an MPFI dual plane intake, I see no reason he couldn't do the same thing and keep his current performance.
Last edited by sstonebreaker; 12-12-2018 at 06:16 PM.
If you actually think that a dual plane manifold on an EFI system is going to produce more low-end torque then you obviously do not know what you’re talking about...
sorry,..
And again for yourself and anybody else that believes that bullshit
go to the FAST forums and you will read hundreds of pages of people who had problems with dual plane manifolds because of the EFI don’t take my word for it
go read it your self
Can you make it work? sure... will it ever work as good as a single plane manifold... no
If you actually think that a dual plane manifold on an EFI system is going to produce more low-end torque then you obviously do not know what you’re talking about...
sorry,..
The formulas for intake wave tuning are well known; it's not even remotely controversial or up-for-discussion, really.
If you know the length and average CSA of an intake's runners you can just plug it into PipeMax and it will tell you @ which RPM which reflected waves will occur at. The intake wave tuning provides a small amount of boost in a narrow RPM range and provide more torque at the RPM that it's occuring at.
The longer runners of a dual plan are harmonically tuned for a lower RPM than single planes. True 19" -21" "long runner intakes" ala TPI or some of the Dodge Cross-rams are working with the 3rd reflected wave which is stronger and WILL end up with more torque lower down, if the CAM timing is time with the resonant frequencies of the intake track.
-Just because you have efi squirting the fuel in, doesn't change that.
The OP isn't dealing with wet flow issues; he's using port injection.
From Grumpy: "setting up a dual plane intake for MULTI PORT EFI, will provide you with good street manors and good mileage and potentially more low and mid rpm torque, but its unlikely to provide more peak rpm horsepower, than a well designed single plane thats cammed and geared correctly ,could. each design has it strong and weak points" http://garage.grumpysperformance.com...-efi-use.2590/
My understanding is that the problem with dual plane manifolds and EFI is SPLIT / DUAL PLENUMS, NOT dual plane manifolds themselves. This is Holley's official stance on the issue. The problem is that with a fully split plenum you've got a MAP sensor that can only measure one half of the plenum and it doesn't know what's happening in the other half. Cutting down the divider or adding a spacer solves that problem. -If you took a TPI, LT, or LS intake and installed a plastic split down the center separating it into two fully separated plenums, you'd be in the same situation with a MAP Sensor in only one of your two plenums. -A dual intake with split / dual plenums (no dividers) is actually an intake with two plenums but a MAP sensor in only one of them. https://forums.holley.com/showthread...l-plane-intake
-I'm going to bet that if you had a dual plane / dual plenum intake and an efi system that could support multiple MAP sensors, you'd still see improved low to mid range torque AND you'd have no problems running the thing. I don't know of any dual MAP sensor EFI systems, though so cutting down the plenum divider is the way to go.
Adam
Last edited by NewbVetteGuy; 12-12-2018 at 07:43 PM.
I think I'm misunderstanding what you're saying, but either way, neither TPI, nor LS intakes have straight runners. TPI runners have a 180 degree bend of the air...
Not remotely straight runners; curviest runners ever???...
Seems to me the OP is doing this to improve power and efficiency. Why try to crutch around the issues of a dual plane if a suitable single plane can be found? I think whatever theoretical low speed torque loss with a single plane will be made up by the improved efficiency of sequential port efi and he will realize gains on the top end.
Seems to me the OP is doing this to improve power and efficiency. Why try to crutch around the issues of a dual plane if a suitable single plane can be found? I think whatever theoretical low speed torque loss with a single plane will be made up by the improved efficiency of sequential port efi and he will realize gains on the top end.
here is where old school meets new school...\\
for a carbureted setup this hold true. the duel plane setup helps low end power...
BUT this does not hold true for EFI... EFI works best 0-100000rpms with a single plane..
Seems to me the OP is doing this to improve power and efficiency. Why try to crutch around the issues of a dual plane if a suitable single plane can be found? I think whatever theoretical low speed torque loss with a single plane will be made up by the improved efficiency of sequential port efi and he will realize gains on the top end.
A good dual plane on 350 cubes can certainly carry power to the OPs cam’s hp peak of 5,600 so any further power “gains” above that RPM are pointless.
Torque down low and in the mid range can be appreciated all the time; more torque at highway cruise rpm == more mpg, too.
A single plane and a dual plane are picking up the same harmonic wave, though so you’re not really generating any more torque at the peak, just moving the peak up or down in rpm.
I think a dual plane will give him more average torque up to 5,600 where his cam runs out of steam and is better matched to his combo; both options would work fine.
spend some time at the FAST sight... these are the professionals that make the EFI.. and they claim your incorrect... but, hey, what would they know..
I’ll check out the FAST site; Danny Cabral runs the Holley Efi forums and has chosen a dual plane, port injected manifold for his personal car.
The Holley guys also aren’t making vague generalities on the issue in the thread I posted a link to; they’ve troubleshot the issue to its root cause (split plenum prevents map sensor from reading both sides of the plenum without a cut divider). -Holley also makes EFI and their take is more nuanced. It’s not a dual plane intake that’s the issue it’s a split plenum that prevents the map sensor from knowing what’s happening on the other side.
Intake wave tuning and enhanced low rpm torque production is unaffected by EFI. Dual plane intakes will make more torque down low.
I’ll check out the FAST site; Danny Cabral runs the Holley Efi forums and has chosen a dual plane, port injected manifold for his personal car.
The Holley guys also aren’t making vague generalities on the issue in the thread I posted a link to; they’ve troubleshot the issue to its root cause (split plenum prevents map sensor from reading both sides of the plenum without a cut divider). -Holley also makes EFI and their take is more nuanced. It’s not a dual plane intake that’s the issue it’s a split plenum that prevents the map sensor from knowing what’s happening on the other side.
Intake wave tuning and enhanced low rpm torque production is unaffected by EFI. Dual plane intakes will make more torque down low.
The air has no idea whether a CARB or an EFI system is attached to the intake.
Here's some more objective data on the subject:
FiTech explicitly says that you should choose a single plane or a dual plane manifold based upon what works best on your engine combo / RPM and their throttle-body EFI will work just fine on both: https://fitechefi.com/faq/what-is-be...lane-manifold/
Direct Quote from the FiTech FAQ site from Bryce @ FiTech: "The intake design has no effect on how the fuel injection operates. It will work with both of them so you should be selecting the intake based on your engine build and use of the vehicle. If you are saying this is a street engine you would usually want all the bottom end torque you can get which is what a dual plane intake will provide."
1. Lots of factory EFI systems, including TBI, came with dual plane intakes and throttle body injection. The problem IS when the MAP Sensor can only get a signal from one bank. GM's engineers were smart, so they created a "Window" / "Channel" between the two sides of the throttle body so that the MAP Sensor can read pressures from both banks. See picture showing this channel; the gasket also has a channel in it for this reason:
2. The FiTech throttle body EFI works perfectly fine even with a full divider dual plane intake (and makes more torque down low with a dual plane intake) because the FiTech engineers were smart and knew this would be a problem and they built channels into the baseplate so that the MAP can read from both banks at the same time.
The PROBLEM only occurs when the throttle body engineers failed to account for this; THEN (and only then) do you need to use a spacer or a dual plane intake with the divider cut down so that the MAP sensor can read both banks. -The FAST engineers failed to address allowing the MAP sensor to be able to read both banks like the GM and FiTech engineers did, so you need to "Crutch" the FAST throttle bodies with a spacer or cut down the divider of a dual plane intake. If you use a poorly designed TBI EFI with a dual-plane intake without a divider or spacer, then the following problem happens and this will screw up your idle and low-speed torque. -The problem is NOT inherent in dual plane intakes with EFI, the problem is with poorly designed EFI throttle bodies and dual plane intakes without dividers and spacers.
What happens when you combine FAST EFI and a split-plenum dual plane intake without a spacer: "Think about what happens in closed loop with a fully divided dual plane as the ecu reads o2 from 1 collector. The o2 is reading 2 cyls on one plane and 2 cyls on the other plane of the intake. Unless the intake has perfect fuel/air distribution plane to plane you can have 2 rich cyls and 2 lean cyls, the o2 then reads this a/f from 4 cyls as an average a/f. If the average a/f is rich the ecu compensates by reducing fuel, everywhere to get the correct average a/f. What just happened to the a/f in the leaner of the 2 cyls??"
Paul, what you've been touting as "The rule" is actually the "Exception to the rule" because of a design problem in FAST throttle bodies.
Hopefully, it's not too shocking that physics don't change just because your throttle body is squirting in highly pressurized fuel... (It shouldn't be.)
*The Defense Rests, Your Honor!*
*MicDrop* -Why is there no 'Mic Drop" emoji, when you need one?!?!?!
Adam
Last edited by NewbVetteGuy; 12-13-2018 at 01:28 PM.
12-12-2018, 02:38 PM
