Eddy RPM air gap/ crosswinds for SB

Posted By: Dakota_Don

Eddy RPM air gap/ crosswinds for SB - 02/26/09 06:46 PM

Has anyone heard this or experienced this.

I called a company to recurve the MP dist for my stroker, and after I gave him the specs they asked " how does it idle" I said kinda rough, I think its in the carb or dist, why do you ask? He said cuz the RPM airgap and the crosswinds port runners are to large and the engine will idle rough. He went on to say he has seen it many times in chevys and mopars, he also said i should use the RPM performer.

I have never heard this before abouth either of the 2 intakes.
Anyone else ?

Posted By: 70AARcuda

Re: Eddy RPM air gap/ crosswinds for SB - 02/26/09 06:54 PM

nope...got a air gap on my duster..

it idles a little rough due to the camshaft 231/237 @.050 duration.

Posted By: Dakota_Don

Re: Eddy RPM air gap/ crosswinds for SB - 02/26/09 06:57 PM

on my old 360 set up, 10.1 cr with XE274H the engine idled rough, and not from the cam.. I beleive its in the carb or the dist.. when the stroker gets back from the shop ill look into it more..I dont know if I wanna do bussiness with this guy again..

Posted By: loco340cuda

Re: Eddy RPM air gap/ crosswinds for SB - 02/26/09 07:13 PM

I have an airgap on my 417 stroker and it idles a little rough but that is becuase it has a MP 484 cam in it (241/241 duration, .484/.484 lift, with a 108 lsa. I think the rough idle is mostly due to the lsa becuase a 241/241 cam in a 417 stroker is not that big of a cam.

Posted By: moper

Re: Eddy RPM air gap/ crosswinds for SB - 02/26/09 10:36 PM

He's mistaken. Not sure who you called, but there are a couple who really profess to "know" a lot, and they are simply putting a huge emphasis on certain aspects of a build. You'd be hard pressed to get an Airgap to idle rough on a 318. The Crosswind has smaller ports, both in length and volume, and the casting quality stinks. So a rough idle can be from poor fitment, or porosity, or port mismatch. The one I tried seeped coolant out the rear corner of the casting, had poorly tapped holes, and was a very brittle aluminum when you did try and tap it... There are reasons they are half the money, and it's not a perfect copy as some suggest.

Posted By: dogdays

Re: Eddy RPM air gap/ crosswinds for SB - 02/26/09 10:52 PM

Moper is right. Not an issue. One ironic thing about the idiotic "advice" is that the Perf RPM and the Air Gap have the same size runners. They are the same intake except the Air Gap heats the intake air less. This may be an issue on a cold start in cold climate but it isn't because of the runner size!

I would not recommend any Performance Products intakes.

R.

Posted By: goldduster318

Re: Eddy RPM air gap/ crosswinds for SB - 02/26/09 11:42 PM

I have an air gap on my 360, the magnum head version. It has a Summit K6901 cam witch is 218/228 duration at .050" lift and about .470" lift at the valve. I have a 4-speed and this thing idles "stock" smooth at 800 rpm. I'd also be lucky to have an 8.8:1 compression ratio.

The air gap works great. make sure your choke works properly. My car has a 600 holley electric choke.

Posted By: autoxcuda

Re: Eddy RPM air gap/ crosswinds for SB - 02/27/09 06:17 AM

Quote:

Moper is right. Not an issue. One ironic thing about the idiotic "advice" is that the Perf RPM and the Air Gap have the same size runners. They are the same intake except the Air Gap heats the intake air less. This may be an issue on a cold start in cold climate but it isn't because of the runner size!

I would not recommend any Performance Products intakes.

R.

So the Performer RPM and the Air Gap are the some exact height? Are they the same manifolds, just the air gap is hollowed out underneath the plenum??????

Posted By: 70AARcuda

Re: Eddy RPM air gap/ crosswinds for SB - 02/27/09 06:52 AM

Quote:

Moper is right. Not an issue. One ironic thing about the idiotic "advice" is that the Perf RPM and the Air Gap have the same size runners. They are the same intake except the Air Gap heats the intake air less. This may be an issue on a cold start in cold climate but it isn't because of the runner size!

I would not recommend any Performance Products intakes.

R.

as far as the crosswind intake...

http://www.popularhotrodding.com/tech/0901phr_mopar_318_magnum_engine/index.html

they ran a crosswind intake on this 318....

Posted By: StandOnIt

Re: Eddy RPM air gap/ crosswinds for SB - 02/27/09 12:47 PM

Hey, thanks for that link, nice read and great info. I also have the PP airgap intake. I did do a little cleanup in the runners and such with a healthy amount of the white in color engine paint with the ceramic in it on the bottom of it to seal the bottom and reflect heat. The carb stays very cool during operation with a Wilson 1" spacer. It works well for me.

Posted By: patrick

Re: Eddy RPM air gap/ crosswinds for SB - 02/27/09 02:12 PM

Quote:

Quote:

Moper is right. Not an issue. One ironic thing about the idiotic "advice" is that the Perf RPM and the Air Gap have the same size runners. They are the same intake except the Air Gap heats the intake air less. This may be an issue on a cold start in cold climate but it isn't because of the runner size!

I would not recommend any Performance Products intakes.

R.

So the Performer RPM and the Air Gap are the some exact height? Are they the same manifolds, just the air gap is hollowed out underneath the plenum??????

yup

Posted By: Dragula

Re: Eddy RPM air gap/ crosswinds for SB - 02/27/09 02:31 PM

That's funny.....I have an air gap and an 850dp on my 360, and it idles at 700rpm. And the carb is an all out race carb, no choke, no choke horn, no nothing. And I ported my intake out even further...I also run the 484 cam, and its a beast with the airgap..

Posted By: Rug_Trucker

Re: Eddy RPM air gap/ crosswinds for SB - 02/27/09 03:39 PM

PHR says 477HP yet the dyno sheet says other wise

What's up with the breather where the fuel pump used to go?

That crank is pretty! Guess at their HP level they could have gone cast for less reciprocating weight?

Posted By: Dakota_Don

Re: Eddy RPM air gap/ crosswinds for SB - 02/27/09 04:32 PM

thak, I never hear of this before and i know some folks here would clear thst up...Cuz i never heard it.

Posted By: dgc333

Re: Eddy RPM air gap/ crosswinds for SB - 02/27/09 08:59 PM

Quote:

Has anyone heard this or experienced this.

I called a company to recurve the MP dist for my stroker, and after I gave him the specs they asked " how does it idle" I said kinda rough, I think its in the carb or dist, why do you ask? He said cuz the RPM airgap and the crosswinds port runners are to large and the engine will idle rough. He went on to say he has seen it many times in chevys and mopars, he also said i should use the RPM performer.

I have never heard this before abouth either of the 2 intakes.
Anyone else ?

FWIW, the ports and runners on an RPM Air Gap and RPM Performer are the same. The Crosswind has slightly smaller runners than the Air Gap.

Also, if you have an MP distributor that was made since about 2002 it can be adjusted as simply as loosening a set screw and adjusting the stops. MP and Mallory sell the same kit that has an assortment of springs to dial in the curve. Its really quite easy to do your self.

BTW, I have a Crosswind on a 360 with a 224/230 @ 0.050 cam and it idles almost as smooth as a stock engine at 650 rpm. It did require 17 degrees of initial advance to obtain the good idle and crisp off idle throttle reponse.