Alternative Port EFI IntakesThis board is for tech discussions and questions about aftermarket port EFI such as the HSR, MR, SR, BBK, FIRST, etc.
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yeah, in one intake I used, I didn't use bungs, it had material that could be drilled out. It was drilled to a .540 hole (hard to find the right bit), ended up finding an oversize(or undersize?) reamer at mcmaster carr. We did chamfer the hole to prevent tearing the o-rings. The injectors will bottom on the edge of the manifold, much like you could do with the bungs.
the fuel rail was little different. same idea, but we only drilled into the rail with around 1/4" drill first. then drilled open to .540", and left material there for the top of the injector to seat. also chamfered the hole for o-ring safety. This gave me a good seat for the injectors, which I will use to make sure the injectors don't move around too much. (planning on maybe .050" movement up and down on the injectors once the rails are bolted down for tolerances and temperature changes.)
in my vortec tpi baseplate, I noticed they stepped the bore, but it was because it gave them material around the injector, since they are so high in the port. I ported that area slightly to get rid of the sharp edges, and reduce the lump that it created.
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Originally posted by robsgta Did any of you guys have any driveability issues at low RPM's after doing the conversion ??
Rob
Not that I can recall. The whole singleplane being bad at low RPM is a wet purpose issue. At really slow speeds you get fuel pudling. But with port EFI, you dont have that issue.
Initially mine had some idle quality issues, but once I got a 'real' throttle body with a decent IAC, it was fine. Now it idles better than comparably-equipped LS1 motors.
FYI: To everyone welding aluminum with a tig, if you sharpen the tungsten to a point like you would do with stainless and use helium as a sheilding gas the aluminum beads turn out MUCH easier and nicer. Just give it a try and let me know what you think.
I have a question to decide which intake I should go with for a similar custom MPFI project. First off my car is just a daily driver, so don't really need to go over 5500 RPM. It's a 350 w/ vortec heads (one day might go 383), I'm planning on using Holley's universal throttle body (1000CFM) or a 454 TBI for induction. My question is, single plane or dual plane? I was thinking about modding a Edelbrock Performer I got for cheap. It's in the preformance range I'll be using (idle-5500), but I don't want to use it just because I got it for cheap. Any suggestions?
On another note, should I go with the 454 TBI (sans injectors) and just find a TBI intake to mod instead of the more pricey Holley unit?
I did read the whole thread. I see a lot of people use a single plane intake, but I didn't really read a reason as to why. I read a lot about using a TPI/LT1 style throttle body, but there was really nothing about using a regular "air cleaner" style throttle body, which is what I want to use.
I did read the whole thread. I see a lot of people use a single plane intake, but I didn't really read a reason as to why. I read a lot about using a TPI/LT1 style throttle body, but there was really nothing about using a regular "air cleaner" style throttle body, which is what I want to use.
Better air distribution. It's a dry-flow system, so a dual plane does nothing really.
You can use a 4bbl throttle body with a normal air cleaner. I used to run a setup like that.. I like the monoblade throttle body better though. A TPI/LS1 throttle body can be used with an elbow too.
What engine is this going on? What is the rest of the combo? What is your reason for wanting a 'normal' air cleaner? I'd try to run the air cleaner in the front fender if possible to get in cold air.. Your engine bay probably gets up to around 160f or higher.
I guess one thing a DP manifold would do is give longer runners to push the basic tuning of the manifold down, and some folks I know say there's a real world benefit to that. Personally, I can say that even my cruddy tune and a relatively large SP + 1000cfm TB (with direct linkage no less), gives up nothing to the carb and Weiand Stealth intake it replaced. MPFI covers a lot of intake manifold design sins.
What engine is this going on? What is the rest of the combo? What is your reason for wanting a 'normal' air cleaner? I'd try to run the air cleaner in the front fender if possible to get in cold air.. Your engine bay probably gets up to around 160f or higher.
It's going on a 350 w/ vortec heads, may go 383 in the future. I haven't picked a cam out yet, I want to go with something that will give me the best MPG possible, that might be asking a lot from a V8, but I'm going to try anyway. The engine is going in my '64 Impala, so I wanted it to appear "stock". I also got a 409 air cleaner for cheap, so I'd like to use that. If I wanted to use a monoblade throttle body, I think I'd just mod an LT1 intake to accept a dist. What are the pros/cons to a monoblade vs 4bbl throttle body?
Figured I should post up a pic of mine as well, not completely finished yet, I bottomed out on money and came up $150 short and couldnt get the AFPR -6 AN that I needed to finish the car. And with school I have no time for a job, so waiting for xmas and the ability to make money.
The system is the Accell Pro-Ram with an Accufab 90mm Ford TB, Precision Turbo 110 degree elbow, FAST Classic Bank2Bank ECM, and 4" piping to get the cone filter under the driver front corner. I have been having trouble routing all the wiring neatly, just dont seem to have the space, plus with the Jacob's unit in there too, and the Passport radar detector/laser jammer and all of the pods mounted front and back in the car it has been ridiculous trying to get everything packed away tightly and neatly.
Is there anyone out there that has fit one under a stock hood?
I got a converted vic jr. intake Holley 4 barrel TB and a 1/2" carb spacer to clear the fuel rails. My air cleaner has a 2" drob base and I have a china make K&N style lid. Hood closes with about 1/4" to spare. I also run solid Moroso motor mounts.
I have a question to decide which intake I should go with for a similar custom MPFI project. First off my car is just a daily driver, so don't really need to go over 5500 RPM. It's a 350 w/ vortec heads (one day might go 383), I'm planning on using Holley's universal throttle body (1000CFM) or a 454 TBI for induction. My question is, single plane or dual plane? I was thinking about modding a Edelbrock Performer I got for cheap. It's in the preformance range I'll be using (idle-5500), but I don't want to use it just because I got it for cheap. Any suggestions?
On another note, should I go with the 454 TBI (sans injectors) and just find a TBI intake to mod instead of the more pricey Holley unit?
Thank you,
Taylor
If you use the TBI (injectors above the throttle blades) you should use a dual plane intake. You could use a carbed intake with an adapter if you wanted. A multi port injected setup (one injector per cylinder) will give you better gas mileage and throttle response.
Is there anyone out there that has fit one under a stock hood?
I fit my old cutler multi-port setup under the stock hood using a small angled spacer to cock down a supercharger top-hat (so it didn't hit the hood) run to 3" tubing and a conical filter behind the headlights. It cost me 47 hp to the wheels.
I fit my old cutler multi-port setup under the stock hood using a small angled spacer to cock down a supercharger top-hat (so it didn't hit the hood) run to 3" tubing and a conical filter behind the headlights. It cost me 47 hp to the wheels.
Not worth it in my opinion.
That's why I went with a smooth elbow this time rather than a hat. I figure the loss won't be as much.
I have read the carb hats for blow thru setups cause some distribution issues but the fuel mixes at the top of the plenum with the carb so in a port EFI setup, i'm not sure if the elbow would cause as much distribution problems as it does in a carb setup
I'm this close to getting the single plane efi plus elbow setup for my turbo project just because i'm nervous about the air distribution with the HSR for the power levels i want
airflow tends to stick to the outside of the bend and to separate from the inside, so you'll tend to get more air/leaner mixture in the cylinders who's runners are below the outside of the elbow. Grand Nationals and their doghouse adapter are a good example of a factory setup that has that problem.
it can be pretty extreme, they sell plates to block off part of the flow on the GN manifolds and even with adding basically a restriction, it works enough better that it's worth doing.
LT1 manifolds are nowhere near as smooth as what we're talking about and have the same problem, when you start running bigger power on them, especially with boost and the rear cylinders tend to go lean and those are the ones that you typically loose first, usually 7, sometimes 5 and 7.
airflow tends to stick to the outside of the bend and to separate from the inside, so you'll tend to get more air/leaner mixture in the cylinders who's runners are below the outside of the elbow. Grand Nationals and their doghouse adapter are a good example of a factory setup that has that problem.
Blue area is restriction.
Different designs lead to different flow patterns. While the best method might be an open element TB with a cut in the hood it doesn't help much with FI plumbing. The hats have substantial power loss, elbows less. And as we all know, all the horizontal intakes have distribution problems too.
My 'first' design may have been better due to me using some stock OE components (vortec TB + hat). Let "GM do the engineering". Maybe airflow was more evenly distributed into the throttle body and then hushed into the cyls. But my last singleplane looked a lot cleaner.
the change to an elbow and single plane is done more for total airflow(thus HP)than it is about distribution. The TPI isn't bad for distribution, it's bad due to poor flow capability.
in order to help airflow on an elbow, you'd want to make a divider than runs parallel with the airflow, and basically diverts the air in half, like two pipes running parallel. this will push half the air on the 'inside' or forward and half the air on the 'outside' or rear. at the outlet, the air will be more evenly distributed, at least, more so than a single pipe.
So i'm caught between HSR for boost or Victor EFI with elbow and Ls1 throttle body for boost.
I'm hearing HSR has rich rear cylinders while miniram tends to go lean. Another guy with a custom tunnel ram type intake with box plenum says he has lean rear cylinders.
SEveral other turbo guys are seeing near even distribution bank to bank in air/fuel ratio and cylinder to cylinder with single planes with elbows
I'm so confused now as I'm hearing two sides to the story. I like the HSR look over single plane but i want the best distribution as possible... airflow between the two is marginal and not a concern as much as distribution
in order to help airflow on an elbow, you'd want to make a divider than runs parallel with the airflow, and basically diverts the air in half, like two pipes running parallel.
I have an Edelbrock single plan setup, and the elbow has a divider in it.
orr98rocz - im boosted and decided to go with a miniram for a few reasons. 1st it fits under a stock hood, otherwise id have gone sp and elbow. 2nd no plenum gaskets to blow out with boost pressure. 3rd it comes in a 1206 ported version that the HSR does not have the meat for. I run DFI and expect to tune our distribution issues. Id go with the SP and elbow. Im starting to regret the MR setup although i have chosen to finish the project as it is. The SP simplicity and ability for alteration is so much better than TPI. Although I have a weakness for tpi that i cant explain. hope that helps some.
orr98rocz - im boosted and decided to go with a miniram for a few reasons. 1st it fits under a stock hood, otherwise id have gone sp and elbow. 2nd no plenum gaskets to blow out with boost pressure. 3rd it comes in a 1206 ported version that the HSR does not have the meat for. I run DFI and expect to tune our distribution issues. Id go with the SP and elbow. Im starting to regret the MR setup although i have chosen to finish the project as it is. The SP simplicity and ability for alteration is so much better than TPI. Although I have a weakness for tpi that i cant explain. hope that helps some.
Tune out? The DFI is sequential and has an injector offset table like the late LT1 calibrations?
Looks like it doesn't have any, but you can drill and tap as many as you want easily.
heh, and mess up airflow...
The wing in the middle is a nice compromise, it essentially splits it into 2 elbows, each with a smaller version of the same distribution problem, but since you're doing it 2x, once to the middle of the plenum and once to the end, it's nowhere near as bad by the time it comes to the runners. Flattening/widening the area where the bend is also helps by in some cases slowing down airflow/increasing pressure making things not as fussy distribution wise.
I'd be all about a design like that if it was setup for a TPI/LT1 style throttle body. Besides the obvious, that it will allow the whole deal to be lower profile and keep the throttle cable on the stock side for most GM's, there are also some tuning and feedback advantages to 2 or more smaller bores than a single large one.
Well... all that being said, I will probably try something with a box on top of the plenum, with a larger area than the plenum opening. The idea is to have a pocket of slower moving air above the plenum to draw from which should stabilize distribution without significantly hurting flow. It will also give a convenient place to put fittings and possibly even mount auxiliary injectors if necessary.
Well i ordered the victor efi, but undecided on the elbow/tb at this moment. LSx style or keep the twin 58mm holley and run custom elbow for that? Then the divider thing, should it be added?
14psi, street tune 
