dan0617 wrote:
That thing sounds badass. Can't wait to see your track times!

How cold of plugs do you run? And what AFR on the wideband do you run when spraying, or do you just go with plug readings when spraying?

My problem was finding plugs cold enough to not melt down when spraying a 250 shot, but hot enough to not carbon foul when driving all day at light load part throttle on the highway. Also that a wideband reading of 11.5 or 11.7 works for an out of the box 125 or 150 shot, but is too lean on a motor that is getting well over 1/3 of it's power from the spray.

I've found that Autolite AR3933's are working great for me. AR3932's carbon up, and AR3934's blister a little on a 250 shot. Have to keep the tune a little on the lean side at part throttle to keep the plugs new looking, then on the rich side on nitrous for safety. On the wideband it is reading high 9's and low 10's, but the plugs look great after a nitrous run.

I thought the wideband was not reading right on the spray but I found a calculator on a nitrous forum that you basically need to figure how much power is from motor and how much is from spray, then figure your motor power at 12.7:1 afr and your spray power at 6:1 afr. Mine works out to low 10's, which is right where I need to be for good looking plugs.

I now believe the wideband is right but the target afr does need calculated this way because when it is calibrated it is done in fresh air, not a mix of fresh air and nitrous. Works for me, I was just wondering if you have a wideband and what it reads when you are spraying the 200.

Also, how is the part throttle light load cruise driveability and street manners when the converter is locked? That is alot of cam, heads, and intake for sure, but you do have alot of cubes to eat it up.

dan0617 wrote:
Mamoram...now that is funny!

Shit, my plenum could fit through that throttle body opening in your plenum. It might even fit down into one of the runners!

By looking at your times with the old setup, you are heading for the 8's!

Matatk wrote:
Sound like some great numbers. What did he have to epoxy on the miniram?

Matthew

dan0617 wrote:
I then was looking at going Miniram but was told that they have problems with some cylinders going lean on nitrous use (still have no idea if that is true or not) and was afraid that 6200 rpms wouldn't be enough to see the true benefit of the Miniram.

BeachBum wrote:
To add to what TPI421vette has said, I do think it bears mentioning, as others have said in this thread, you can't go wrong with either the MR or SR..... they're both good intakes and a country mile better than "any" long tube runner set-up.

Thus, if you chose an MR for your 350.... still no worries, you'll run great, and if you don't mind running a converter a little loose, everybit as good as the SR, if not better.

Good luck with whatever you decide !

BeachBum wrote:
Quote:

88BlackZ51 wrote:
Beach, I wouldn't think that combo would of reved high enough to fully take advantage of the miniram. Actually 11.60 is good for that combo. What was the diff in 60/MPH?

More cam would have probably helped the Miniram, but it would have also helped the Superram. The real problem in comparing the two intakes with a hyd roller cam, is that you're limited by rpm and really no matter what you do, below 5500 rpm on a 350-383, the Superram makes considerably more torque, thus accelerates faster with street type converter/gearing packages. With a Solid Roller cam, the operating range maybe 5200-7200 rpm, it then becomes clear the Miniram is vastly superior. But, in my opinion, shifting at 6200 rpm, the Superram is a tough to beat intake if you're going to use a street friendly tight converter.

In my test, the Superram's advantage was mostly in the 60 ft time..... although it did trap speed 1/2 mph higher as well. This is because in the operating range of 4200-6200 rpm, the Superram made more average HP than the Miniram in my application. On the 60's, the converter with the Superram flashed to somewhere around 3200 rpm, whereas the Miniram, the same converter flashed a couple hundred rpm lower, keeping in mind, the torque you have below the converter flash point does matter because it does effect the amplitude of the converter stall.

On your 421 cubic inch application, the Miniram is the better choice in my opinion, simply because the Superram begins to inhibit the rpm capability with a big cube motor.... I've seen dyno's with similar set-ups to yours, but with a Superram, where the Motor made 520 HP @ 5200 rpm and 570 ftlbs @ 3800 rpm...... very stout, but the MR would be a bit more balanced and probably produce better et's.... albeit it would probably be closer than you think. With the same motor, a 560 HP @ 5800 rpm - 530 ftlbs @ 4500 rpm would be close to reality with the MR. In addition, your 421 cubic inches are providing the low to mid-range torque necessary to get your butt in motion that the smaller 350-383's just can't provide.

BeachBum wrote:
Quote:

tpi421vett wrote:
Looking good Todd!!! I don't think you will be too disappointed with the miniram. I think they work well on big inch motors. Jeb ported mine and got 308cfm out of it. But I also tried one of Jebs converted single plane intakes. I lost 3mph, and 2 tenths from the miniram. I dunno... maybe it's because I run a wet 200 shot, and it didn't like his plenum box "adapter" for the t.b.

Wow...I didn't know that, thanks for the heads-up !! Thats a big loss at your power level and indicative of over 30 HP, and more like 40-50 HP loss. Was it a plate system you attached to the horizontal plenum box/throttle body junction ?