4k stall + nitrous

K

KzooMuscle

Forum Member
I own a Mustang, and I currently have a 4000 stall awaiting install. My plans are to eventually run nitrous (100-125 shot) this summer along with the basic bolt ons. My tuner/installer told me a 4000 stall would be too loose with nitrous and would be "hard to handle". I have heard multiple opinons, all varying from a 4000 stall being perfect to it being useless on the spray. Do any of you have experience with this combo that could give me some facts rather than opinons.

Thanks
 
That really depends on a bunch of factors. What are your cam spec's at .050 (duration and lobe sep are most important). What is the max rpm you plan on shifting at? Who's converter is it (so i know which core they started with). All this plays out in if it's too loose or too tight.
 
MJR Payne said:
That really depends on a bunch of factors. What are your cam spec's at .050 (duration and lobe sep are most important). What is the max rpm you plan on shifting at? Who's converter is it (so i know which core they started with). All this plays out in if it's too loose or too tight.
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Stock cams for now, probably 6200-6500 rpm, and it's a Dirty Dog converter. If you need specifics to further help you let me know, and I can get whatever specs you need.

It's an NPI motor, I want to see what the most I can get out of it is before going PI. Eventually down the road I plan on doing cams but nitrous will be my drug of choice at the moment.

If I need to get it re-worked, I'll probably decide to just sell it and get a custom one made through Precision but I'd like to hold off on that until I get a more serious motor with cams.

I just know stall's are extremely beneficial to autos, esp. 4r70w's so I'd like to get one put in asap.
 
i dont think your spraying enough to really need a nitrous only converter. id have no issues running the converter your getting.
 
KzooMuscle said:
Stock cams for now, probably 6200-6500 rpm, and it's a Dirty Dog converter. If you need specifics to further help you let me know, and I can get whatever specs you need.

It's an NPI motor, I want to see what the most I can get out of it is before going PI. Eventually down the road I plan on doing cams but nitrous will be my drug of choice at the moment.

If I need to get it re-worked, I'll probably decide to just sell it and get a custom one made through Precision but I'd like to hold off on that until I get a more serious motor with cams.

I just know stall's are extremely beneficial to autos, esp. 4r70w's so I'd like to get one put in asap.
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It should be ok. Just note the engine rpm fall back with the juice on during the shift. Should fall back somewhere between 1000 to 1200 rpm's
 
Try it, you already bought it. If you don't gain at least 8 mph in the 1/4 mile on a 100 shot, its probably slipping too much. Hope you have sticky tires.. Goodluck.
 
johnquick648 said:
i dont think your spraying enough to really need a nitrous only converter. id have no issues running the converter your getting.
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I second that
KzooMuscle said:
Fall back? I've never heard that term before.
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The amount of RPM you lose during a shift.

Was this converter custom made to your engine to be at 4000, or was this an off the shelf item advertised to be 4000? That will play a huge factor, as if it's an off the shefl item i have seldome seen a converter go to it's advertised stall speed in anything close to a stock motor set up, but may net you the 4000 on nitrous.

You already have it. throw it in and see what happens! BTW my PTC on a HCI pushrod motor goes to 3400 on motor on the brake, and on spray goes to 4200 when the brake is released. and i shift at 6000
 
Billydroveit said:
I second that


The amount of RPM you lose during a shift.

Was this converter custom made to your engine to be at 4000, or was this an off the shelf item advertised to be 4000? That will play a huge factor, as if it's an off the shefl item i have seldome seen a converter go to it's advertised stall speed in anything close to a stock motor set up, but may net you the 4000 on nitrous.

You already have it. throw it in and see what happens! BTW my PTC on a HCI pushrod motor goes to 3400 on motor on the brake, and on spray goes to 4200 when the brake is released. and i shift at 6000
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I'm the second owner. The converter isn't an off the shelf item. The original owner had it re-worked to 4000-4200rpms from the orginal stall, decided to go in a different direction or didn't need it anymore, I forgot which one, and decided to sell it. "It has a small front cover for a maurauder for lighter weight, small pattern, 9.5, safely rated for 7000rpms and 450 whp, carbon graphite clutch" yada yada yada

What's your stall rated at? 3400 or 4200?
 
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Specs Below:

Small pattern design with front cover for extended rpms.

More than twice the OEM lockup surface with high carbon graphite clutch.

9.5 inch diameter

Safely rated for 7000 rpms and 450 RWHP.

Drain plug installed for easy servicing.

Furnace brazed pump with hardened pump drive hub and rigid balloon plate.

Roller type stator clutch for maximum street ability.

Furnace brazed turbine with tig welded tips for durability.

Sealed torrington bearing construction.

small pattern

8 lbs lighter than stock unit empty and holds 2 quarts less fluid for less rotational mass.

Fluid balanced.

Damper style lockup piston for less abrasive application.
 
KzooMuscle said:
I'm the second owner. The converter isn't an off the shelf item. The original owner had it re-worked to 4000-4200rpms from the orginal stall, decided to go in a different direction or didn't need it anymore, I forgot which one, and decided to sell it. "It has a small front cover for a maurauder for lighter weight, small pattern, 9.5, safely rated for 7000rpms and 450 whp, carbon graphite clutch" yada yada yada

What's your stall rated at? 3400 or 4200?
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It was never "rated" it's a custom PTC built for a stock motor and nitrous. They built it for the power curve of a stock motor with a mild cam and head. I don't remember what specs were used as it was originally in a 2V car but stalled the same in both.
 
So what you are saying, if mine is "rated" for 4000-4200 rpms I should expect it to jump anywhere in the 5000rpm range on spray??
 
KzooMuscle said:
So what you are saying, if mine is "rated" for 4000-4200 rpms I should expect it to jump anywhere in the 5000rpm range on spray??
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If it was made to be 4000 to 4200 on motor and depending on it's slip rating it may jump to 5000 on spray. But only hiting it with 100 to 125 i doubt it will go that high. Only one way to find out! Hell depending on how loose it was built on spray you might just drive through the converter and it never really locks up. Converters are a tricky science, and there's a reason guys who know how to make them work make the big bucks. Mine was nothing seriously special and it was over 650 bucks...
 
So it's a hit or miss....so many variables play a role in a stall it's hard to determine one apart from another really from what it sounds like.
 
KzooMuscle said:
So it's a hit or miss....so many variables play a role in a stall it's hard to determine one apart from another really from what it sounds like.
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You can tell one from the other...but ALOT of things play into stall converters. WEight of car, gearing, cam, heads....you get the idea. What was 4000 behind one motor most likely won't be behind another.

Off the shelf converters are rated in a wider range because they are built to suit a few different applications. They can work great, we have an off the shef converter in my budies car, and it work fantastic. But there could be improvement in having one made spesifically for hiscar. That's why an off the shelf can be had from 380 up, and customs usually start at 600.

It's hit or miss on off the shelf converters. Hell even custom ones may need to come out after being installed for a tweek. This is one area i like tht i can just make a call, and tell a guy what i have, and what i want, and a few weeks later i have it.
 
I spoke to a tech over at Precision, he told me mine could work if tuned properly, ie: lockup in 2nd. but is still questionable if it would be more beneficial in the long run or limit the drive ability of the car. On that note, he did say to take the advice of Lidio (who will be doing some work to my car soon) since he will be tuning it in person to tell me what stall would be ideal. Like you said, so many variables play a roll in converters that it would just be simpler to get the car tuned with nitrous, and see what my curve looks like in order to predict what stall I need and get my converter re-worked or just go through Lidio and Precision to make me a custom one. I would like to get this stall done asap but I guess this is one of those situations that if I want it done properly I need to be patient.

BTW, my converter was $750+ so it wasn't an off the shelf product. I'll probably just end up sending it back and having them re-stall it after I get tuned to be honest. I'll only have to pay for shipping :)
 
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