is my brand new 4200 vigilante to much stall for h/c and nitrous?
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From: memphis tennessee usa
Re: is my brand new 4200 vigilante to much stall for h/c and nitrous?
Originally Posted by jimbob65
I use Flash stall as a gage....gives me an idea how much extension a converter will most likely have (that's not set in stone). Converter extension is what your really worried about. To much and you'll loose efficiency in the upper rpm's, to little and you'll more than likely not have enough rpm at your extension point (rpm you drop down to after gear change), and be to low in the rpm band. The PI 3200 I use works great for Nitrous on my stroker but I shift at 6950rpm's and my extension (on Nitrous) drops down to 5700 rpms. If I were to shift my engine at say 5700rpm's my extension would = my shift rpm which is real bad for efficiency. My converter (off Nitrous) has a shift extension of 5200, which is a little low. I have heard from many racers over the years that "NA" you want between 1000 to 1400 rpms extension drop on the shifts for the best power band (this depends on engine power band and converter efficiencies at those rpms). However, some of these converters will get real loose when hit by Nitrous and some won't. This is where peoples experience with a particular converter comes in handy. This is why I recommend no PI stall above 3200 with Nitrous. The "3200" converter already will more than likely flash to 4K for your combo, for good launches. And have a tight enough extension to hold maybe up to a 250 shot of juice. As you can already tell there's going to be a trade off in Flash stall and extension "NA" vs. "N20". Now, for Yank converters I recommend the SS3600 which will have about the same characteristics as the PI 3200. I have no experience with Fuddle so, I can't make a recommendation on their verters.
"n20fed"
I only have experience with PI's 9 1/2 inch lock up converters. But if your seeing what I have read about your problem, then yes. Your extension is too high killing your efficiency. The "triple" lock up converters only apply to Turbo or Big Nitrous shot. These guys you a manual lock up switch, usually in second gear and above. Where your mid range torque is so high, that you don't need converter extension to help you accelerate. I would recommend either having your converter re-stalled lower "say 500 rpm's," which is supposedly = 1000rpms less of extension. Or change to a different line of converter with something more proven to hold horse power. You have a turbo 400! So, their are a ton of great companies. Coan, Continental are just a few...
"n20fed"
I only have experience with PI's 9 1/2 inch lock up converters. But if your seeing what I have read about your problem, then yes. Your extension is too high killing your efficiency. The "triple" lock up converters only apply to Turbo or Big Nitrous shot. These guys you a manual lock up switch, usually in second gear and above. Where your mid range torque is so high, that you don't need converter extension to help you accelerate. I would recommend either having your converter re-stalled lower "say 500 rpm's," which is supposedly = 1000rpms less of extension. Or change to a different line of converter with something more proven to hold horse power. You have a turbo 400! So, their are a ton of great companies. Coan, Continental are just a few...
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Joined: Nov 1998
Posts: 115
From: WA
Re: is my brand new 4200 vigilante to much stall for h/c and nitrous?
"red96z"
You can try a PI 3600 which flashes to 4200-4400 NA. On the jug maybe 4800-5000? Depending also how hard your shot comes in....any higher PI stall and you'll blow through the converter....PI's are not the most efficient converters when you go above the 3200 stall....If you already have that big PI4200 forget the Nitrous shot...unless it's small....
You can try a PI 3600 which flashes to 4200-4400 NA. On the jug maybe 4800-5000? Depending also how hard your shot comes in....any higher PI stall and you'll blow through the converter....PI's are not the most efficient converters when you go above the 3200 stall....If you already have that big PI4200 forget the Nitrous shot...unless it's small....
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Re: is my brand new 4200 vigilante to much stall for h/c and nitrous?
Jimbob, why is that when you go above a certain stall it blowes through? Also if my converter is that loose and I'm only picking up 150hp on a 250 shot, how much e.t. and mph do you think I'm leaving behind. Currently I'm putting down 550hp.
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Joined: Nov 1998
Posts: 115
From: WA
Re: is my brand new 4200 vigilante to much stall for h/c and nitrous?
That's because as a converter gets looser (extension closer to your shift point) it takes less power to blow right past where you would shift and just sits on the extension. You could always try it if you already have the converter. My bet, as soon as you have traction (and hit the 150 shot) you'll just sit right at your shift point, killing all efficiency. You might and would probably have a better "ET" but not by much and your mile an hour won't make sense vs. ET. Like I said if you got it why not try it. Maybe you got a little tighter version of that converter (there are production difference which cause a little difference in stall). If you got a free re-stall though, I would stall down to a max of 3600 (4200ish flash NA....)
You could be losing a full second in ET and 10 miles an hour! All depending on combo and how fast your already going (ET and mile per hour wise).
You could be losing a full second in ET and 10 miles an hour! All depending on combo and how fast your already going (ET and mile per hour wise).
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