Intake Mods, do they really work?

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MRL Performance

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Whats up my Mopar Maniacs? I know I have not been on here for a while, its been a very rough summer. As some of you might have noticed, I am no longer a Vendor on the "Bodies" sites. We had to drop it due to funding. Some may also know that my wife, the greatest thing to happen to this old boy, has a brain tumor. Its not life threatening, but it really affects quality of life. The meds to help with this tumor are NOT cheap, and they went way up this year. But we are getting thru it.

Anyhow, I thought a Tech page would help some of you out a bit. Intake mods, are they worth it? Some are, some not so much. Im going to look at 2 types of mods here.

First is the old tried and true "gasket match". There is a right way and a wrong way to do it. I will detail the right way another time. But in general, if your intake port is within 1/16" of your head port, you will not gain hardley anything opening it up to the same size as the heads. The biggest thing is making sure the intake port is NOT bigger than that of the head, thats bad. If its off by, say 1/8", then yes you will gain enough power to make it worth your while.

Next is a simple little mod. We have all seen it, but does it work? This mod has to do with the center divide on a dual plane intake. Does cutting it down help? I have tested this so many times, and yes it does help. You could run a small open spacer and get the same results, but not everyone has the room to do that. And its free, spacers cost money.

What I have here is a MILD 408 stroker that we tested this on this week. Here is the combo

360 30 over 4" stroke = 408
Speedmaster heads
Scat stroker kit w/hyper pistons
Lunati HR cam 231/239 .530/.550 lift, Mild
9.4 to 1 compression
Eddy AG intake
1.5 Comp rockers
FBO ignition
Nothing real fancy here, just a solid street engine.

Without any mods to the intake here is what we got:
RPM TQ/HP
3000 501/296
3500 514/341
4000 527/404
4500 515/442
5000 496/473
5300 482/487
5500 463/484
Not to bad, loads of torque and pretty good top end. It started to taper off at 5300rpm. Peak TQ was at 4000rpm 527tq and peak HP was at 5300 487hp

Now I cut the divider down about .250", lets see what happened
RPM TQ/HP
3000 506/299
3500 513/344
4000 528/404
4300 532/437
4500 529/453
5000 514/491
5200 503/500
5400 487/501
5500 479/501
5600 467/500
5700 458/499
5800 446/494

So there you have it. Same engine, same tune, same dyno, same day. Peak to peak may not seem like much, but we gained more on the top end than we expected. Almost 20HP more at 5500rpm even more at 5800 but we didnt take the first runs that high. So is it worth it? Hell YES!
And its FREE POWER!!!!! You dont have to have a fancy Mill to cut it down, you could use a 4" angle grinder to get the job done and who doesnt have one of those.
 
Hey Mike, sorry to hear about your wife
glad to hear it is not life threatening but I can see how its drains your time and what not
 
Thanks for the thread. Are these tests specifically aimed towards HP and Torque regardless of MPG and drive-ability? I have been trying several options on my new setup and am considering an open spacer on my dual plane intake but this is not for racing, only cruising and mild street use.
 
Mike, nice to see you post again. I too am glad your wife's tumor isn't life threatening. I wish you all the Best.
 
Mike, good to hear from you again. That is a test I haven't been able to do myself yet. Thanks for posting!
 
Mike,I am all too familiar with illness,as both myself and my wife have multiple sclerosis. I am more fortunate,as I took measures and took charge of my health. I have gotten back some of what I lost,but my wife has continued to slide downward. I really get it,the frustration,the expense,the almost complete lack of support or help.I have been reading a great deal about stem cells,and it seems this area of research is very promising for many types of illness or injury. Hoping this becomes a practical treatment for all soon.

It's very good of you to remember the fabo crowd during your time of crisis. Heck taking a break might help you!
i know for a long time I was consumed by my illness,it was all I could think about.Remember to care for yourself as well.

Oh,and welcome back!
 
That's a pretty awesome improvement. So, you just cut down the divider .250? Any other blending in the plenum? Was wondering if I ruined my ld4b or not.

duster 8-1-15 009.JPG


duster 8-1-15 002.JPG
 
Mike, sorry to hear about your wife. Nice to see you are still lurking in the shadows though. I was wondering why we hadn't seen any posts from you in a while. I hope things start turning around for you and your wife.
 
Thanks for letting the forum know about this tip for power Mike.
Hope all goes well with your wife.
 
forphorty said:
That's a pretty awesome improvement. So, you just cut down the divider .250? Any other blending in the plenum? Was wondering if I ruined my ld4b or not.

View attachment 1714968293

View attachment 1714968294
Click to expand...
Yup just cut it or grind it down and clean it up a little. The plenum on yours looks good, no worries there. It seems to help the carb get a much better signal and lets the entire engine have access to the entire carb.
 
seabee said:
Thanks for the thread. Are these tests specifically aimed towards HP and Torque regardless of MPG and drive-ability? I have been trying several options on my new setup and am considering an open spacer on my dual plane intake but this is not for racing, only cruising and mild street use.
Click to expand...
Mods like this are aimed directly at a more efficient running engine, which will in turn give you better driveability and FE.
 
BTW, Thanks for the prayers, its been a rough road. She has had this for a few Years now, and we have tried different meds and doses. She will be going back in for testing this Nov to see if we are shrinking the tumor or hopefully Killing it. We will see.
 
yes hopeful its killing it! keep us updated lots of people on here care about you and hoping for the best! take care and good luck.
 
Sorry to hear about that Mike, my wife has some auto-immune disorders and is on expensive medication as well. She's able to function and everything but it can be very draining at times. So I know what it's like to have to deal with everything associated with that. Thanks for the tip on the divider, I'll have to try that.
 
What size carb was used on the dyno tests? I'll assume that like an open hole spacer, the gains will be more pronounced on an engine with a smallish carb (street).
 
I got to thinking about this and how it gives a better signal to the carb. Do you think it would be a benefit or not to someone with a throttlebody EFI system like FITech, Holley Sniper, FAST EZ-EFI etc?
 
I had this spacer from a previous car. Put it on and Drove around for a bit today. Will see how it goes.......
7FB36C32-6A3C-4E9A-A078-9D6DBC9D6B6A_zpsnt0iwuxf.jpg
 
seabee...that's technically not a spacer...it's an adapter plate for spreadbore to square bore carbs and intakes, but it will work as a spacer as long you check real close for vacuum leaks.
 
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