Plenum,2925?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

JoePorting
Guru
Guru
Posts: 2997
Joined: Mon Jun 14, 2010 3:16 pm
Location: Lake Elizabeth, CA

Re: Plenum,2925?

Post by JoePorting »

Your manifold is good. Not much you can do with a manifold.

If the rules are open on the heads, I would have gone with 2.10/1.50 valves. Those heads are cheap enough that you can buy several sets and do your own experimenting.
Joe Facciano
levisnteeshirt
Guru
Guru
Posts: 1912
Joined: Tue Aug 18, 2009 2:53 pm
Location:
Contact:

Re: Plenum,2925?

Post by levisnteeshirt »

88bluestar wrote: Tue Apr 02, 2019 2:23 pm 2925 super Vic intake untouched currently, and was considering just blending the transition of the port roof on the plenum.
Should I do the blending or leave it as such with this engine combo
And should any more porting be done on the head intake ports.

1/4-3/8 size dirt track oval, wide curved turns, American racer kk704 tire
Current engine is a 355, 93 ethanol free gas, 9.9:1 comp
EQ 350H hybrid vortec(1205 fel pro matched) 5 angle perf valve job, ferrera 2.02/1.60 valves, no bowl work other then the blend near the valve seat, and the port match
244/248 .528/.538 lift 105-adv 4 def solid lift cam
6.125 Honda rod end,
45 lbs 4340 crank
370 gm SRP flat top piston std tension
780 cam Holley 4bbl mech sec
2925 super victor intake. 1 5/8”-3 collector.open exhaust
3900 ft above sea level if that matters

Rules
Any intake but carb mount surface is 7” max from block to intake carb mount, any 4bbl carb.
.540 intake/.560 lift rule(solid flat tappet)
7000rpm rule.
How much does the car weigh ?
Carnut1
Guru
Guru
Posts: 4659
Joined: Tue Jun 11, 2013 6:32 pm
Location: Melbourne fl.

Re: Plenum,2925?

Post by Carnut1 »

dart 215e.jpg
Just an example how I do a Victor jr. tall. Thanks, Charlie
You do not have the required permissions to view the files attached to this post.
Servedio Cylinder Head Development
631-816-4911
9:00am - 9:00pm EST
88bluestar
Pro
Pro
Posts: 378
Joined: Sun May 21, 2017 7:39 pm
Location:

Re: Plenum,2925?

Post by 88bluestar »

levisnteeshirt wrote: Wed Apr 10, 2019 11:46 am
88bluestar wrote: Tue Apr 02, 2019 2:23 pm 2925 super Vic intake untouched currently, and was considering just blending the transition of the port roof on the plenum.
Should I do the blending or leave it as such with this engine combo
And should any more porting be done on the head intake ports.

1/4-3/8 size dirt track oval, wide curved turns, American racer kk704 tire
Current engine is a 355, 93 ethanol free gas, 9.9:1 comp
EQ 350H hybrid vortec(1205 fel pro matched) 5 angle perf valve job, ferrera 2.02/1.60 valves, no bowl work other then the blend near the valve seat, and the port match
244/248 .528/.538 lift 105-adv 4 def solid lift cam
6.125 Honda rod end,
45 lbs 4340 crank
370 gm SRP flat top piston std tension
780 cam Holley 4bbl mech sec
2925 super victor intake. 1 5/8”-3 collector.open exhaust
3900 ft above sea level if that matters

Rules
Any intake but carb mount surface is 7” max from block to intake carb mount, any 4bbl carb.
.540 intake/.560 lift rule(solid flat tappet)
7000rpm rule.
How much does the car weigh ?
3,000 lbs
levisnteeshirt
Guru
Guru
Posts: 1912
Joined: Tue Aug 18, 2009 2:53 pm
Location:
Contact:

Re: Plenum,2925?

Post by levisnteeshirt »

Have you ever tried a RPM type intake and compared lap times ?

https://youtu.be/_klUTPMRhxE

The blue camaro has a 383 , 220 rhs steel head . RPM intake , 650 dp 13-1, flat tap cam ,, the 2 cars behind it are full blown 18degree 421's or 434s ,, 15-1 , unlimited engines ,, they can't catch the blue car ,, I ported the RPM intake and did the 650 ,, you might try a dual plane for a limited set up ,, the unlimited cars would pull away on a restart , ( sometimes they ran the 2 classes together ) , but you can see just doing laps ,, they really can't catch him like most would think ,, blue car driver is far less experienced too

He went to a single plane and slowed down

It was funny ,, both of the unlimited guys came over and wanted to look at his engine after
88bluestar
Pro
Pro
Posts: 378
Joined: Sun May 21, 2017 7:39 pm
Location:

Re: Plenum,2925?

Post by 88bluestar »

Something to check somewhere down the road. What I have now is what I have, got a tight budget. Have to see how the power band is on the track, lot of uncertainty right now but I’m being conscientious of not going too overboard.
steve cowan
Guru
Guru
Posts: 2253
Joined: Wed Jul 27, 2011 5:22 am
Location: brisbane AUSTRALIA

Re: Plenum,2925?

Post by steve cowan »

88bluestar wrote: Wed Apr 10, 2019 10:58 am Likely not going to touch the ports, the heads have a 1205 fel pro match currently. With the track being 3/8 mile dirt and likely a hooked up track most of the time I’m focusing on making as much mid range torque as possible. The cam will be advanced 4 degrees per MIke Jones recommendation, which I also think is part due to the rod length as well. Should I do more to the plenum?

Heads have just a 5 angle job and blend and according to the EQ sales director he say it would’ve been better with 1.94/1.50 valves but per Mike Jones suggestion I went to a 2.02/1.60 valve so it would breath up to the 6500-7000 rpm
Blue star-
i think you are good to go.make sure there is no casting flash inside the runners.
i would not worry about making it shiny in the runners-pretty don't make power.
go with what Mike Jones recommends and dont get caught up in the TUNED BY COMMITTEE CAMP
thats a French Grimes quote - im sure you have heard of him.
good luck keep us posted,i think it will run good :)
steve c
"Pretty don't make power"
zums
Guru
Guru
Posts: 1355
Joined: Sat Dec 08, 2007 10:57 am
Location: south jersey

Re: Plenum,2925?

Post by zums »

Well,cant post pics, says files too large, your layback on the end runners looks ok but the real problem with that manifold is the center runners, take a holley 4 hole gasket and lay it on the top of the manifold and you will see how much they are choked off, you can radius/favor the top of the divider toward the barrels a little to help line of sight, blend into the runners about 1/2 inch, that will keep you out of the runner csa which for your application is already plenty big, if you want a cheaper spacer alternative you can get a plastic or phenolic 5-7 degree taper cloverleaf, they help distribution with that manifold also.
Tom
88bluestar
Pro
Pro
Posts: 378
Joined: Sun May 21, 2017 7:39 pm
Location:

Re: Plenum,2925?

Post by 88bluestar »

Super sucker spacer should be here today. Will send pic on intake when I can.
SchmidtMotorWorks
Vendor
Posts: 11003
Joined: Mon Apr 11, 2005 2:30 am
Location: CA

Re: Plenum,2925?

Post by SchmidtMotorWorks »

It looks like you removed the overhang on the top of the ports.
Generally that will lose power.
Helping to Deliver the Promise of Flying Cars
zums
Guru
Guru
Posts: 1355
Joined: Sat Dec 08, 2007 10:57 am
Location: south jersey

Re: Plenum,2925?

Post by zums »

SchmidtMotorWorks wrote: Wed Apr 10, 2019 8:06 pm It looks like you removed the overhang on the top of the ports.
Generally that will lose power.
If you are talking about the plenum shot 5 posts down from the top of this page i agree, as far as the other pics on page 2 there is still enough roof radius to work
Tom
JoePorting
Guru
Guru
Posts: 2997
Joined: Mon Jun 14, 2010 3:16 pm
Location: Lake Elizabeth, CA

Re: Plenum,2925?

Post by JoePorting »

zums wrote: Wed Apr 10, 2019 8:22 pm
SchmidtMotorWorks wrote: Wed Apr 10, 2019 8:06 pm It looks like you removed the overhang on the top of the ports.
Generally that will lose power.
If you are talking about the plenum shot 5 posts down from the top of this page i agree, as far as the other pics on page 2 there is still enough roof radius to work
Tom
That's so far up stream I couldn't imagine it making too much difference.

Jon, does Edelbrock do a lot of design testing with there manifolds or do they just go with the best guess? I thought they extended the four inside intake walls too far into the plenum area.
Joe Facciano
SchmidtMotorWorks
Vendor
Posts: 11003
Joined: Mon Apr 11, 2005 2:30 am
Location: CA

Re: Plenum,2925?

Post by SchmidtMotorWorks »

JoePorting wrote: Wed Apr 10, 2019 10:10 pm
zums wrote: Wed Apr 10, 2019 8:22 pm
SchmidtMotorWorks wrote: Wed Apr 10, 2019 8:06 pm It looks like you removed the overhang on the top of the ports.
Generally that will lose power.
If you are talking about the plenum shot 5 posts down from the top of this page i agree, as far as the other pics on page 2 there is still enough roof radius to work
Tom
That's so far up stream I couldn't imagine it making too much difference.

Jon, does Edelbrock do a lot of design testing with there manifolds or do they just go with the best guess? I thought they extended the four inside intake walls too far into the plenum area.
Tons of testing on the part being developed and all relevant competitive manifolds.

A single manifold will have many prototypes made and compared typically.

The testing is much more careful and controlled that what you see on YouTube videos. The dyno operators / calibrator follow test plans that are reviewed by multiple engineers. Evey pull is planned and data is carefully collected by people with engineering degrees in the subject of testing. Most have OEM experience.
This is essential for development of late model stuff.
You won't beat OEM stuff today by guessing or rules of thumb.
Frankly, unless you change the requirements there is not much on the table these days.
On the Coyote manifold I developed there were 5 major concepts and many variations of some of them. Many 100's of dyno pulls.
You need very good data management to make sense of the data. If you are just looking at power curves you might as well not even start.
Helping to Deliver the Promise of Flying Cars
SchmidtMotorWorks
Vendor
Posts: 11003
Joined: Mon Apr 11, 2005 2:30 am
Location: CA

Re: Plenum,2925?

Post by SchmidtMotorWorks »

JoePorting wrote: Wed Apr 10, 2019 10:10 pm That's so far up stream I couldn't imagine it making too much difference.
Upstream Is WHY it makes a difference.

A lot of the things that optimize a manifold are not part of the conventional discussion of CSA and flow numbers etc.

I gained 35 HP on 550hp engine with a geometric property that I never have never seen discussed in a forum or book.

A dyno room with emotional people chasing power curves and cheering about gains would NEVER find it.

And a flow bench test would not find it.
Helping to Deliver the Promise of Flying Cars
GARY C
HotPass
HotPass
Posts: 6301
Joined: Tue May 14, 2013 10:58 pm
Location:

Re: Plenum,2925?

Post by GARY C »

SchmidtMotorWorks wrote: Thu Apr 11, 2019 1:44 am
JoePorting wrote: Wed Apr 10, 2019 10:10 pm That's so far up stream I couldn't imagine it making too much difference.
Upstream Is WHY it makes a difference.

A lot of the things that optimize a manifold are not part of the conventional discussion of CSA and flow numbers etc.

I gained 35 HP on 550hp engine with a geometric property that I never have never seen discussed in a forum or book.

A dyno room with emotional people chasing power curves and cheering about gains would NEVER find it.

And a flow bench test would not find it.
Is the size and shape of the return pressure wave entering the plenum what your concerned about here?
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
Post Reply