So much for the Modman....

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This guy got his modman working fine. You need more engine
[ame]https://m.youtube.com/watch?v=vgPaiFT0550[/ame]
 
EL5DEMON340 said:
This guy got his modman working fine. You need more engine
Click to expand...

Working 'fine'. Okay. However I'm willing to bet the guy in the video could make more power with another intake. Course I'm sure he knows that already, as I'm pretty sure he built that with compromises to make the 3x2 fit.

Rat Patrol got his modman running really great. Now he's trying a new option that ought to work better. Much respect to you Rat. You got the most out of the modman, and now you're trying something new to see if you can get more.
 
It is true to say that the signal drop off doesnt show so badly with large cube motors - but its also true that fuel distribution issues might only be identified by running another intake that is known to work......and atm there's only the Eddy dual quad that would provide a similar comparison.

No point on comparing a drag pack...we a,l know they work....but we all know you need a hole in the hood as well!
 
hey Rat. A couple of questions?
Are you running an exhaust scavenger system or any kind of scavenger ?
And any type of venting on top end of the block? .
 
I agree with Uhcoog! I own a modman and want the best performance that I can get from it until I find something that is better..

Rat KEEP UP THE GREAT HELP BROTHER!!
 
I would take everything with a grain of salt until the OP posts valid results with a dual plane and
the original 800 cfm carb with no other changes.

I know, I know....you checked everything else and I believe you but humor me on this one point.

Anxiously waiting the conclusion of this story. Thanks for posting.
 
Well had a chance to do some setups yesterday . Seems to have a better burn with the idle control turned off with the msd 6 . all the cylinders are burning .

I used rats set up . turned it down a bit . THE secondary's seems to be performing now.
But as soon as the money is available .I will be changing to dp
 
cnddodgehead said:
hey Rat. A couple of questions?
Are you running an exhaust scavenger system or any kind of scavenger ?
And any type of venting on top end of the block? .
Click to expand...

No mate..no scavenger system of any sort...and only an oil vapour puke tank....no Pcv to the carbs.

I cannot BELIEVE how much more mid-range this new intake has...all my buddies have commented!
 
Old Man Mopar said:
I would take everything with a grain of salt until the OP posts valid results with a dual plane and
the original 800 cfm carb with no other changes.

I know, I know....you checked everything else and I believe you but humor me on this one point.

Anxiously waiting the conclusion of this story. Thanks for posting.
Click to expand...

OMM - The Modman was run in both single a dual carb configurations - the only comparison I can provide is a dual carb vs dual carb...as the Eddy has no provision for single carb useage

But considering the Modman single carb only MPH'd at 110... and the Modman duals mph'd at 114.... Theres not a lot of point worrying about the single configuration.
 
cnddodgehead said:
Map63Vette makes a valid point! there are no other options for a carb setup that keeps the monies in prospective!

I have the mod with a 750 vac sec on mine . I have yet to have the car on the road . But having said that . During some run time in the garage . I have issues with cyl 7 and 8 . both have wet plugs after trying the secondary's .

Now Listening to these negative comments about the intake from people makes me wonder?
Click to expand...

You know that the vac secondary's will never open running in the garage, they must have a load on them (driving).
3310 ?
 
I am get some response in the garage . But will need to have some further testing once on the road.
Looking around for possibly a 750 dp. I have an 850 dp but might be to much for the single carb set up on the mod .
 
So folks I have the cuda out and have had my first experience with the mod intake .
Using a 750 vac secondary .
out of the hole is ok . has a flat spot around 3000 to 3500 rpm then starts to clime slowly (for my liking ) seems to smoothen out at 4000 rpm than at approximately
. 5000 to 7000 rpm it feels like a 250 shot of nitrous !
Any feedback at making it more stable is helpful
 
cnddodgehead said:
Map63Vette makes a valid point! there are no other options for a carb setup that keeps the monies in prospective!

I have the mod with a 750 vac sec on mine . I have yet to have the car on the road . But having said that . During some run time in the garage . I have issues with cyl 7 and 8 . both have wet plugs after trying the secondary's .

Now Listening to these negative comments about the intake from people makes me wonder?
Click to expand...

Just an update the issue was not the intake found the issue . bad needle on the float.
 
Hi all - a while back I promised that Id do a genuine comparison between the Modman intake and the Edekbrock 5.7 dual quad dual plane.

I experienced significant tuning issues with the Modman running both single and dual carbs - (333 RWHP) and it only really worked half way decent when I installed a full height divider (346 RWHP)

Below is the dyno chart ( same dyno..similar atmospherics) showing three (3) runs

The BLUE line was the Modman with divider - this netted a 11.9@ 114mph

The MIDDLE RED is the EDDY - same carbs - 360 rwhp

The Upper RED is the Eddy with twin 1" 4 hole spacers. - 368RWHP


The Eddy had a home port match to the 6.1 heads.

I think this proves conclusively that the Modman is a JUNK NA intake.

My guess is that the carbs are losing about 15 rwhp to the EFI....


 
cnddodgehead said:
So folks I have the cuda out and have had my first experience with the mod intake .
Using a 750 vac secondary .
out of the hole is ok . has a flat spot around 3000 to 3500 rpm then starts to clime slowly (for my liking ) seems to smoothen out at 4000 rpm than at approximately
. 5000 to 7000 rpm it feels like a 250 shot of nitrous !
Any feedback at making it more stable is helpful
Click to expand...

What you describe is what I experienced - slow response until 4000rpm and then it felt like a cam kicking in.......trouble is at the track....this showed as an appalling 60 ft and 1/8 mph.

Take your car to the track on slicks....orvfit a full height divider 1/2" thick .....I dont think youll be happy with what either will tell you.
 
I'm curious to see what mine will do with the port fuel injection setup. I've been meaning to dyno it for a few years now, but just haven't really made it a priority. I have zero idea how good my own tune it though, aside from reading numbers off a wideband O2 sensor.
 
Well my issues were with the vacuum secondary . I had a 750 on mine . had a flat spot at 3000 to 3600 give or take .I tried to play with different springs but I wasn't happy. decided to rebuilt my 4781 850 dbl pump . that I had from my 512 rb .after talking with rat and vette here thought . give it a try.
well the difference is very very noticeable. The motor loves the carb . so much for fuel economy .
still have to do some adjusting on the first shot I have a bog then it grabs. The flat spot is about half a second . Feels like its flooding then it goes like a banchee!
Maybe a pooling issue or maybe the shot from the secondary is too early ?
 
i am with a 750 vacuum too. Fantastic street carb. But on the track it feels like missing something in the end.

will change to a 750DP soon. I have this Blake Carbs made one here but needs a rebuild.

Are you using 50cc pumps? both?
 
cnddodgehead said:
Well my issues were with the vacuum secondary . I had a 750 on mine . had a flat spot at 3000 to 3600 give or take .I tried to play with different springs but I wasn't happy. decided to rebuilt my 4781 850 dbl pump . that I had from my 512 rb .after talking with rat and vette here thought . give it a try.
well the difference is very very noticeable. The motor loves the carb . so much for fuel economy .
still have to do some adjusting on the first shot I have a bog then it grabs. The flat spot is about half a second . Feels like its flooding then it goes like a banchee!
Maybe a pooling issue or maybe the shot from the secondary is too early ?
Click to expand...

Sorry to be negative...but I found even with twin carbs I gad a bog......until I fitted a divider.....

The double pumper covers the lean condition .......but its not enough to completely cover the signal drop out.

Theres two issues....lack of fuel on tip in due to plenum size (use DP) and signal drop out...to which theres no real fix imho.... Although a divider helps...
 
Had a big win this weekend!

Since fitting the Gen 3 Hemi Ive been fighting an uphill battle to get a decent balanced carb induction system happening.

Finally got it close to sorted with a combo of spacers and weights.

Of course proof will be at the track...but the car feels strong and will tear the Mickeys from stand still.

Here's the background for those that care.......

First there was the Modman with a single carb -,if I knew then what I know now...I wouldnt have bothered....insanely large plenum and a vac secondary carb was never going to be a happy marriage - and although it ran 114.44 mph...the 60ft was embarrasing!

Things didnt improve much when I went duals...a little better 60 ft..but still terrible - mph went down to 111 !!

Fitting a divider helped the 60 ft to 1.86... Still ****..but mph improved to 113.8

So with no other sensible option at the time....I turned to the Edelbrock dual plane dual quad - the 60ft improved to 1.79.... But the intake was only available with 5.7 ports and the plenums were small....and my mph suffered down to a best of 112mph

Obviously a port mismatch didnt help.

So I tried some 4 hole spacers - kazaam!! 60ft dropped to 1.70!!.. But my mph went backwards..to 111!!

So I asked around and considered opinin was the AF was probably hitting the intake floor and causing disturbance....so recently Ive been testing an open spacer and a 4 hole...here's the preliminary results....

1" 4 hole on top, 1" open underneath - the car felt much quicker through the gears.....but the old lean bog returned like the Modman...even with super sized pump shooters.

So I tried 4 hole on top of an open 1/2" spacer. This helped...but I could feel the mid range wasnt quite there and it still bogged if I slammed the pedal.

So then I tried the 1" open on top of the 4 hole - the mid range returned...and the bog lessened.

Then Moper from the forums suggested I add weight to the air doors of the AFB carbs....I started with a total of 1/2ounce on each..,and the bog disappeared but I could tell it was still fluttery down low.

So today I added another 1/2 ounce....

....and the thing now has balls!! It turns the MT Drag radials with ease on the launch...theres no 'dip' when I nail it in 3rd...and the induction sound is a beautiful roar!!

I think I can finally say Ive got that part of the problem licked.....now Ive just got to get a decent tuning tool and port match the intake to the heads....

Stay tuned! — feeling excited that the motor is starting to do what it should.
 
Interesting to read your struggles with the carb setup. I think I'm probably glad I stumbled upon my Megasquirt setup or I would probably be equally frustrated. I knew it had to be possible to tune a carb to work with my engine, but I wasn't sure how much I would spend in the long run and how much headache it might be. A different style carb might be the easier way to get there (something with a little easier tuning in the places you need maybe?), but nice to see you're making progress either way. I always felt my car was lacking something when it was carb'd.
 
why is the XV the expensive trash? I have one because it has the Retro style. I have no issues but I am also not able to compare. Did someone compare the XV with manifold 'xyz' ?
 
Is anybody surprised a 1405 in the middle of a fabbed intake doesnt work? Would you install a Geo Metro carb on your 408 stroker? 1405's are a mid performance street carb that require a strong vac signal. Didnt all the manifolds and carbs cost as much as a harness and pcm to make it work correctly with FI? Dont get it.
 
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