newschool72

iTrader: (12)

hey guys im the one that started the " ez efi on a vic jr " thread a while back. got another one for u. im thinking about going with gmpps new dual plane for my LS3 heads instead of the vic jr. im not sure which would be better for my setup. i know the dual plane is a better street intake in a carb setup mainly because it has longer runners that have better velocity for CARB SIGNAL . this is where it gets tricky for me. with the fast EZ efi im not looking for that velocity for carb signal. the ecu is monitoring the fuel. how much does that effect the low end advantage of the dual plane over the single plane. anybody got a clue ?

speedtigger

iTrader: (16)

With a throttle body injection, I don't think you have to worry as much about drivability issues like you might with a carburetor. However the difference in power curve will still be relevant. I have only seen one dyno test on an engine equipped with a new GMPP L92 dual plane and have never seen comparative dyno tests like we have available for the Performer RPM cathedral port intake. So, it is hard to say specifically where the power curves will cross vs. a single plane intake.

For comparative purposes, on an LS1 engine with a midrange cam. the power curves cross around 5,000 RPM. The dual plane has an advantage below 5,000 RPM and the Victor JR. has an advantage above 5,000 RPM. I would assume the L92 head intakes would have similar properties, but we have no data that I am aware of to confirm this.

You will have to decide if your intended purpose is to have more low and midrange torque or more higher RPM and peak power.

newschool72

iTrader: (12)

thanks for the input..... the cam im running ( comp lsr269-13 ) has an rpm range of 1800-6700. im thinking the dual plane will complement my cam better if the intakes perform w the efi similiarly to the way they perform w the carb. just not sure how much carb signal has to do with the difference.

speedtigger

iTrader: (16)

I would not even consider the who "carb signal" issue with fuel injection and a cam your size. The runner length will be the important issue. If I were building your combo, I would choose the dual plane.

newschool72

iTrader: (12)

yea, you are right. gmpp intake is just sooo expensive. anybody want to buy a new vic jr for l92 s ? ill probably put it up on marketplace soon.

rojs234

iTrader: (5)

The signal to the carb may not be an issue, but my personal opinion is.... when you have a single plane intake with a large plenum, large ports in heads(L92/LS3) a street type convertor, and moderate gearing, you're going to have slow air movement at low RPM's and the fuel stands a good chance of puddling in various cylinders or falling out of suspension. I tried to run a very similar engine to yours with a single plane and a carb and while it had unreal power at higher RPM, I never could get a double pumper to work right at full throttle at low RPM's. Maybe I'm not the ACE TUNER that some of the other fellows on here are, but I think you would be happier with the dual plane. My .02 worth.....Ron

newschool72

iTrader: (12)

thanks Ron, for the input . anybody found a good price on the gmpp dualplane for L92s ?

rojs234

iTrader: (5)

I would like to add a couple things. If you intended to run about a 3500-4500 stall covertor behind it, maybe even with lockup since you're using a 200-4R, it might work fine with a single plane. Actually, I'm hoping you will try the FAST EZ EFI with the single plane before you sell it, if that is what you decide on. I would really like to see how it reacts when you floor it at 1500 RPM from a standstill. If it will handle all four barrels at that RPM and load....I want one!

newschool72

iTrader: (12)

yea, i remember u saying that u would watch that other tread closely and i havent made my mind up for sure yet, but i really dont want to monkey with this car much once i get it finished. its just too ez to screw up paint and stuff when i start wrenching on things.

melsie68

iTrader: (8)

What is the application? Is it the '72 Camaro in your screen signature? Stick or automatic? How heavy is the car? What size tire; gear ratio? List the cam specs too and that could get us a better idea of what you are after.

Honestly, I hate to throw you a curveball after all these recommendations for a dual plane, but I suggest you go with the open plenum manifold. If you have at least 3.73 gears (or numerically higher) and a 3000 stall converter or more, you will not even notice any loss of torque at low speed. If you are stick shift, absolutely go with the open plenum. Personally, I think dual planes do not belong on anything but pick-up trucks and grocery getters. Times have changed and with as good as these late model cylinder heads are, the torque production down low is outstanding. Don't get caught up in thinking like we used to do on SBC's. Just my thoughts...

newschool72

iTrader: (12)

it is a 72 camaro. the specs are LS3 crate engine w a stock long block except the cam ( comp cams LSR269-13...607-621 /219-235 at .050,113 lsa),1 7/8 longtubes, fast EZ efi and vic jr (?). the trans is a 2004R w a lockup converter stalling at 2200rpm. the rear is an 8.5 10 bolt w posi 3.42s. the tires are 25.7 in tall (275-40-17s). my target weight for the car is around 3300 lbs. i want it to haul a$$ but drivability is more important.

NemeSS

iTrader: (127)

What u askin for l92 jr?

newschool72

iTrader: (12)

no sir, i have a l92 jr, but am questionng if a gmpp dual plane for l92s would be a better chioce.

Pop N Wood

iTrader: (1)

I've made the same argument in the past.

speedtigger

iTrader: (16)

I have heard this argument that LS motors have outstanding torque down low before. The problem with that argument is that it is untrue comparatively speaking. LS engines have more top end than the older style V8s. In general, the LS engines typically require a larger stall speed converter than a small block Chevy for a given application. The combination or longer connecting rod and higher flowing heads move the torque band up.

There is no "new rule" for LS motors. Dyno tests and graph show on the cathedral or port motors show that the power band crosses at about 5,000 RPM. The dual plane is much stronger down low, while the single plane is stronger above 5,000 RPM.

I would make your decision based on your torque converter choice and intended power-band. If you have a street cruiser with a stall converter 3000 or lower, you will definitely appreciate the characteristics of the Dual Plane. If you have a 3500 or larger converter and plan on shifting above 6500 RPM, I would chose a single plane.

rojs234

iTrader: (5)

Couldn't have said it better myself. Oh, come to think of it...I have.... a couple of times, at least.

Pop N Wood

iTrader: (1)

Slow day at work so here I go again. You guys are massively oversimplifying this. Maybe that is all the OP wants, to collect votes and to go with whoever sounds the most convincing. In that case he got an answer.

I disagree about LS motors not being different than first gens. Roller cams and roller rockers allowing more aggressive cam profiles, EFI and massively better heads and more than 3 gears in a transmissions all combine for a much better all around engine. I don't think anyone is arguing "new rules" so much as don't get stuck in the past and miss out on the advantages of the new motors.

I think it is backwards to say LS motors require bigger stalls and more accurate to say you can get a lot more out of your LS while still staying streetable if you build for bigger power at higher RPM and run a stall to match.

IMO the big argument is just how much low end torque do you think you need? A lightweight car with typical street tires can't make use of all that low end torque, so why not trade some of it for top end power? And yeah, 90% of the time I'm not beating on my car. But at the same time WTF cares what the peak torque numbers are when you’re not beating it or towing something? These engines do not become unstreetable just because the intake runners got shorter and more direct (think no flow distribution problems). The guy has a 6.2L fuel injected V8 in a 3300# car. He would have to go way large on the cam to lose too much “drivability”, whatever that means.

IMO choose the intake in concert with the cam. They both can be used to tune the power band up and down. Then choose your stall and gearing to match the engine and the rest of the car. Not the other way around.

And rojs234, you were the one who gave me the courage to drill all the press in bleeds out of my DP in the first place. Tightening up the idle air bleeds got rid of the off idle bog on my single plane LS2. I am definitely no super tuner but your advice worked for me. I would be amazed if the OP has a bog with the Fast EFI.

speedtigger

iTrader: (16)

It is important to note that my opinions are primarily based on LS dyno tests by magazines and by engine builders, not on older motors. Dyno tests where back to back results are graphed and shared.

In these dyno tests, on mid range street engines, the dual plane picked up 25-30 ft. lbs of torque in the 2500-3000 rpm range. The single plane enjoyed a 12 to 15 peak horsepower advantage in the 6000 to 6500 area. The horsepower peaks in these tests occurred at the same RPM.

For your average street engine, giving up 12-15 peak horsepower is not a deal breaker by far. I don't want anyone to think that if they go with a dual plane that their car will loose a lot high RPM horsepower. It is just not the case on these street engine dyno tests. I can guarantee that you will feel 25-30 ft. lbs of low end torque a hell of a lot more than 12-15 peak horsepower.

Pop N Wood

iTrader: (1)

And if the 25-30 extra lb-ft of low end torque just make the tires spin faster, will I feel that also?

speedtigger

iTrader: (16)

If you have a traction problem, that is probably an individual issue that you can choose to address or not I guess.