As some of you know I decided to try another intake manifold. I've been using a ported Edelbrock Performer RPM dual plane manifold pretty successfully over the past couple years. I've tried a few different spacers with the dual plane including 1/2" open wood, 1" open plastic and lastly a Wilson tapered 4hole 1" spacer. I recently purchased a Dart oval/rect port single plane manifold from Lukovich Racing. Yesterday I ran the car with no spacer and timing/jetting the same as my last outing two weeks ago with the dual plane. I figured the new intake already has more plenum area and I'm somewhat limited with hood clearance on the new intake. I can fit a 1/2" spacer and still run the breather. With a 1" spacer and breather the hood won't close. Below are a series of split analysis from the last outing with the dual plane two weeks ago and yesterday's outing with the new intake.

Old Manifold 6/12/04

DA 60' 60-330' 330'-660' 660'-1,000' 1,000'-1,320
4,172 1.548 2.952 2.516 2.190 1.863
3,851 1.531 2.952 2.511 2.188 1.860

New Manifold 6/26/04

DA 60' 60-330' 330'-660' 660'-1,000' 1,000'-1,320'
3,557 1.565 2.933 2.474 2.151 1.830
3,650 1.577 2.932 2.487 2.161 1.833

So, from the way I read this the car was .02 quicker from 60-330, .02 quicker from 330-660, .03-.04 quicker from 660'-1,000' and .03' quicker from 1,000-1,320. It looks to me like the car is making more power at every increment other than 60'. I made 5 runs yesterday and launched from 1,600-1,700 (always 1,600 with the dual plane as that's where I had the best success given my chassis setup). My 60' times from the previous outing with the dual plane were 1.548, 1.531 and 1.539, which is about what I would have expected given the DA. Yesterday my 60' times (in order) were 1.565, 1.577, 1.587, 1.607 and 1.594. All of these runes were made from the same lane at the same track with the exception of the last run from last night. I tried the right lane just to see if the 60' time would be different as several other racers had tried both lanes in time trials and reported better luck in the right lane. The question is whether my car is spinning or if somehow the 60' time was killed by the new manifold. I'm inclined to think it was over powering the tires/chassis for two reasons. One, judging by the splits the car was making more power at every increment of the track in similar air. Two, the 60' times continued to worsen throughout the day as the air got a little better (more power). I'm militant on my tire pressure settings, burn out procedures, staging, launch RPM and shift RPM.

Here are two full runs made at within 200' DA difference with the old manifold vs. new:

3,851' DA with old intake
1.531
6.994
97.58MPH
11.042
120.90MPH

3,650' DA with new intake
1.577
6.996
98.60MPH
10.99
122.73MPH

So the car is slower by .046 in 60', even at 660' with +1 MPH, and ahead at the stripe by .052 and almost 2mph. Assuming the 200' difference in air was worth .01, the new intake showed an improvement of almost .05 even though the 60' was nearly .05 slower. If the 60' comes around to the same as the old intake then the new intake would be worth ~.09 and +2 MPH. I'm sure the new intake isn't optimized. I will be trying a 1/2" open spacer as well as jetting and timing on a dyno in the next couple of weeks. I'm curious to see what you all think looking at this data.

Thanks.

Ken,
Thanks for the post. good info graemlins/thumbsup.gif
What are the RPM numbers?
My experience has been if the majority is above 4-4500 & you are going above 62-6500 the single plane is going to make more usable power when racing.
For the street the RPM will normally make more low end with no loss to about 6000 which makes it a very "drivable" intake.
That said, on a bigger engine the single plane makes so much low end power that the numbers sometimes become academic :D
As an example, a 489 with only 9.8 compression had over 500 lbs ft from 2900 on with a Vic jr & AFR 315 heads.
It probably had very good torque lower but that's as low as I could load the thing on the dyno reliably

Little refresher here.

What cam and heads?

Originally posted by Wolfplace:
Ken,
Thanks for the post. good info graemlins/thumbsup.gif
What are the RPM numbers?
My experience has been if the majority is above 4-4500 & you are going above 62-6500 the single plane is going to make more usable power when racing.
For the street the RPM will normally make more low end with no loss to about 6000 which makes it a very "drivable" intake.
That said, on a bigger engine the single plane makes so much low end power that the numbers sometimes become academic :D
As an example, a 489 with only 9.8 compression had over 500 lbs ft from 2900 on with a Vic jr & AFR 315 heads.
It probably had very good torque lower but that's as low as I could load the thing on the dyno reliably Thanks, Mike. My converter stalls to 4,800-5,000 on the transbrake. I only use the transbrake to check the stall speed as I race in a footbrake class. I have my shift light set at 6,050 RPM for 1-2 and 6,250 for 2-3. I didn't record the runs with my playback tach yesterday cause I hate the additional distraction in a bracket race. However I've checked it before and I usually shift ~400 rpm late 1-2 and 200rpm late 2-3. Therefore the shifts were probably happening ~6,400rpm yesterday. I could spin it harder if need be. Only possible weak link would be the rods. they are forged LS-7 rods. I have a lunati racer series crank and wiseco pistons. I have spun it to 7,400 on a chassis dyno before. I'm looking at this manifold as an investment. I hope it nets better 60' times in subsequent outings as it's already pulling the rest of the track harder. That said, it will make a nice addition to my next planned engine ;)

Originally posted by thrasher:
Little refresher here.

What cam and heads? Thrasher,

Canfield 310cc heads with mild port work. Cam is Comp solid roller .650/.660 248/254@.050 108 LSA. Compression is 10.37:1.

Absolutely no question it is going to run a lot better with the single plane.
I wouldn't be to concerned with anything below where you are running the engine in regards to power, just drivability & I am guessing you have at least as much if not more torque then the 500 I posted at lower RPM's
I would bet there is a lot more with tuning graemlins/beers.gif

As for your rods, although I am not advocating it back when I didn't know any better :D I ran those rods (actually the L88's) in a 482" in a Vega that I shifted at 82-8400 & went through the lights at about 8600.
32" tire, 5.13 or 5.38 gear (even tried a 5.57 once) & a little over 150 MPH,, you can do the math
I had to run pins in the rods like an aluminum rod have to keep the bearings from turning in the cap from rod distortion :eek:

Dang man that is a lot of rpm.
What cubes?

Originally posted by thrasher:
Dang man that is a lot of rpm.
What cubes? 482. .125" over 454.

And this was in the mid 70's back before I had sense enough to know you can't do this :D

Worse yet this thing was shifted 3 times, no electronics, no rev limiters, shift lites etc. Just a clutch peddle, line loc, Huge mechanical tattletale tach & dumb luck I guess :(


Here's a pic of the car at Fremont/Baylands & the engine.
http://wsm.ezsitedesigner.com/share/scrapbook/19/190264/Vega_2.JPG

http://wsm.ezsitedesigner.com/share/scrapbook/19/190264/Vega_Engine.JPG

==

Hey Ken, sorry for wandering off your post a little :D

Ahhh, those classic M/T covers. :cool:

ken with as much rain as we have had around our neck of the woods i wouldnt judge the sixty foots just yet as you know the 60s vary in track prep

Good Info as Usual Ken..

Makes me want to test out the RPM for comparisons on my motor...

Love those pictures Mike..... graemlins/thumbsup.gif

That's cool Mike :D
I really did enjoy those pics graemlins/thumbsup.gif

I was actually meant Ken.
Guess I need to direct those questions graemlins/clonk.gif

I bet that 482 sounded evil at 8600 rpms, cool stuff. graemlins/thumbsup.gif

ttt

Ken, re the rods. After 25,000 street miles and massive abuse( 7400 rpm redline), the only thing salvageable from the old 427 were the old L88 rods, Crane cam and the block. I would NOT consider them a weak link with the 'gentle' rpms you swing, imho.

Theoretically, single plane gives carb a bit less signal, ok wait, a DIFFERENT fuel signal as opposed the dual plane. Since I cannot comment on the direction of change, but there is a change. ASSUME its weaker singal. Jetting changes are mandatory if fuel signal changes, weaker signal, smaller jets, stronger signal- fatter jets.

My bet, you lean it out by 2 sizes ( and 1 size bigger booster) and it will pick up more.

You are not done yet Sir, with your testing! ;)

Originally posted by 427L88:


Theoretically, single plane gives carb a bit less signal, ok wait, a DIFFERENT fuel signal as opposed the dual plane. Since I cannot comment on the direction of change, but there is a change. ASSUME its weaker singal. Jetting changes are mandatory if fuel signal changes, weaker signal, smaller jets, stronger signal- fatter jets.

My bet, you lean it out by 2 sizes ( and 1 size bigger booster) and it will pick up more.
;) Gene, Are you sure about that? I'm thinking weaker signal, FATTER jets and vice versa. Since the signal is weaker, less fuel is pulled out of the jets, but overall air flow through the manifold is close to the same. Wouldn't fatter jets be needed to flow the same amount of fuel to keep the air/fuel ratio the same?

Originally posted by von:
[QB] I'm thinking weaker signal, FATTER jets and vice versa. Since the signal is weaker, less fuel is pulled out of the jets, but overall air flow through the manifold is close to the same. Wouldn't fatter jets be needed to flow the same amount of fuel to keep the air/fuel ratio the same? I'm inclined to agree with you. The signal to the carb is decreased yet the plenum volume of a typical single plane is nearly double that of a dual plane, nevermind factoring spacers, etc... However, I'm certainly not an authority on the matter. Coincidently my plugs (checked them after the first pass with the new intake) looked a little leaner than they normally do (as did my tailpipes). The air was so bad I didn't bother rejetting.