I am going to be finishing up the install of a SN2000 on a 87 IROC 350 700R4 putting out 304RWHP before supercharging. I would shift the car at wot at 6000RPM's when racing . When the supercharger is installed what is a safe shift RPM for the SN2000. I don't want to spin the supercharger to fast and have it blow up. Is it ok to shift at 6000 RPM's?
I am running a 255lph pump and 24lb SVO injectors. I have a MSD retard box , R43TS plugs and Accel supercoil. I also installed new MSD wires, cap and rotor. I will set the fuel pressure at 48PSI. I will be using water injection pump for now and adding a intercooler later. I will be using the stock chip until I get a new one burnt. Does this sound safe to you guys? I am installing a Fuel pressure gauge and boost/vac gauge to keep a eye on things. Does this sound like I have the bases covered? I am new at forced induction and want to make sure I have the bases covered. What do you think?

 

look at your maximum blower rpm to see what the fastest you can drive the blower is, but i doubt you will be max-ing out the blower, so go dyno tune it, and shift before you run out of fuel. lol


adam

 

post your pulley sizes (crank and blower), and i'm sure Willie can tell you where to safely shift at....

later
larry

 

The supplied pullies I had with my SN blower were 5.75" and 3.25". I later bought a 3.50" from Paxton, which allowed me to run my engine to 5,200 rpm without exceeding impeller redline (38,000). In order to take the engine to 6k, you'll need a 4.00" blower pulley, which Paxton does not make. I did exactly this and had one custom made for $100. The results were disappointing. Yes, I could take my engine to 6k (where I shift), BUT the problem is the impeller spins slower, thereby creating significally less boost at any given engine rpm. It was a total waste of $100.

With an extremely low redline of 38,000 rpm, there isn't much you can do with different pullies to match its redline to the engine's. The only alternative is to shift at 4,861 rpm's (with the 3.25" pulley) to prevent overreving the blower. Doing so however, does not allow you to take the engine up to where it's still making power (5k to 6k rpm range). I call this a blower/engine mismatch. My conclusion is if you want to spin your engine to 6k, the SN blower is not for you.

 

First off-dyno tune it with a wide band on it!
I just traded in my SN89 for a new SN2000. It came with a 4.25 inch pulley, and those are still available as are many parts from Paradise wheels in San Marcos Ca.
My engine pulley is 7.5 inch.
Divide 7.5 by 4.25=1.7647058. Then that times 4.41(internal gear ratio of the blower)=7.7823525, then that times 5500rpm=42803rpm for the blower.
Shift at 6000rpm=46694rpm for the blower.
So it depends on your pulley sizes.....
If you change the fluid frequently , only use type f trans fluid, run the cooler on it, and only occ'l over-rev by a bit it should last quite awhile.
BTW-I shift wot at 5500rpm, follow the above and my sn89 had 30K miles and bearings etc looked great; the only reason I had to trade it in was my own fault...I didn't cut off the top of the shock mount low enough and with engine movement it hit and cracked the case...I'm still kickin' myself!!!
Mine's a Vette so less room, but make sure you have enough clearance!

 

....It came with a 4.25 inch pulley, and those are still available as are many parts from Paradise wheels in San Marcos Ca.
My engine pulley is 7.5 inch.

I believe there is a difference between the serpentine belt drive and the triple v-belt design. I'm not sure which one you're referring to, but my SN2000 for an '87 had the triple v-belts. At the time I inquired about a 4-inch blower pulley, Paxton was servicing these units and was told the largest they had in the triple v-belt was a 3.50".

If you change the fluid frequently , only use type f trans fluid, run the cooler on it, and only occ'l over-rev by a bit it should last quite awhile.

I guess not all planetary ball-drive Paxtons (SN series) are created equally. I owned mine for 2-1/2 years and it needed rebuilding THREE TIMES!! I babied it, changed fluid in it every 1,500 miles and I had Paxton's oil cooler too. I also never revved it past 37,500, which was Paxton's recommendation, yet it continued to fail. I do not know if the maintenance recommendation or redline has changed in the last two years, maybe my information is oudated.

Bottom line: Everyone has different experiences with the same product. Play it safe.

Willie

 

It sound like I made a big mistake with this blower. Does Paxton make a head unit that will work with my engine? I got a great deal on it and now I see why. I don't drive the car much. I have cancer and am very sick most of the time. I want the car to be able to run correctly. Larry will tell you I am a car guy that hates for anything to not be right. What is the best thing to do? I can't afford a D1SC so I need a head unit that I can replace this one with? I will measure the pulleys tomorrow. Willie or Larry anyone what do you think?
Drive it I will try calling them tomorrow. That is were I found the missing brackets at.
Larry check out my web page and you can see on page 8 were I just installed the head unit.

 

Drive it I will call tomorrow and see what they say. That is were I found the missing brackets at and they seem like nice people.
I am running the surp belt system. I called Pardise Wheel several times today but had to leave a voice mail. I will try again tomorrow.

 

Chris,

I know i mentioned to you, that i didn't recommend that blower, though it will work...

Willie is the "The Man" when it comes too those Paxton's, he has a ton of experience with them...with all kind's of data to back up his results.

I believe that the next head unit bigger from paxton is a NOVI 2000, and would involve a serious amount of fabricating, check out this thread---> installing a Paxton NOVI 2000 on a 3rd gen

Personally, you got it installed, definately drive it, but use caution...start off very slow and capture alot of data with the scanner... watch the 02 volts and the knock retard...

later
larry

 

I have the sn2000m and i have had great....LUCK with it TG!!!! I ahve heard a lot of problems with them, and some with no problems such as my self. I would suggest getting a transmission cooler and a fan to cool the oil. Craig @ paradise wheels said that an oil cooler will dramatically increas the life of the supercharger. You can get a larger pulley from paradise wheels too for about 80 bucks. I have the 3.5inch pulley and plan to get a 4inch soon.

good luck! Hope your luck with the sn is as good as mine.

 

Raiden what type of power was your car putting out before the supercharger was installed. I left Craig several messages today. I have the oil cooler and will be installing it. I have been very sick today so I am just going out to the garage to measure the pulleys.

 

The paxton cooler sucks! Get a good tranny cooler and a fan!

Hope ya feel better. My Z ran a 14 flat with out the charger. Ran a 13.0 with the charger...actually a 12.9 @109mph.

 

I ran a 12.96 at 110.57 MPH without the supercharger and was hoping for mid to high 11. with the supercharger.
I just measured the pulleys and they are 3.25 and 5.75. I guess I will be ordering some pulleys for now.
I am running the SuperRam on the engine and the inlet tube rubber sleeve was to short. I have to get a rubber sleeve that is 5.25 inches long because of the difference between the stock TPI and the SuperRam..
There are some pics of the supercharger install on my web page page 8 and 9

 

I talked to Craig today at Pardise Wheel and ordered a 4 inch pulley and 5.25 inch rubber sleeve for the intake track. Like Willie said they have to make the pulley. I will install that next week and go from there.
How many pounds of boost will the 4 inch pulley put out? I was thinking that would drop the boost down to about 5 PSI. What do you think? I am running 10.1 compression so that would be better for the engine anyway.
Craig is a great guy to deal with. He said if I am not happy with the head unit he will work out a deal on a supercharger and build it to my needs. You can't ask for more than that.