Does anybody know what Weiand reccomends as a maximum safe rpm for a 142 blower. I want to speed mine up, not blow it up. I have e-mailed Holley tech. with this question twice. No response from them.

I dont know what they "recommend", but on my drag car, I used the smallest pulley they had because my engine size was 388 cubic inches and I used to spin it up to 6800 rpm every shift. Never had any problems.

What do you guys run at the track with those blowers?

O.K. If you were turning 6800 with a 6" bottom, & 2,5"? top pulley I should be safe. I don't spin mine above 6000.
I still would like to know if Weiand states an rpm limit.
Mwilson, in answer to your question. I have run 12.31 @ 108 & change. I would really like an 11 something, though.

Yours tunned more for racing or does it have pretty good street manners?
Ive always thougt about buying one of the single carb blowers

The only thing that isnt street friendly on my car is the 3500 stall converter. It's a little mushy around town.
You can look at my profile for specs.

would you not recommend a 3500 for street use? I was thinking bout getting one, because of my cam. Should i shoot for like a 2800?

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350 bored 40 over flat top hyper pistons silver lite.Comp Cam net lift 488 net duration 230, 110 center. Roller tip Rockers 1.52 ratio. Heads mild port match. Edelbrock intake RPM Profromer 1 inch spacer, Holly 670 street avenger carb, headers, th350 w/ shift kit, rollcage, 4inch hardwood hood, dual exhaust, 3.53 posi,245/50/16 radials

I have a 3800 stall but its not very loose,
It flashes around 4000 but i can ride on the hywy no problem at 2500-3000, i shift gears manually so i wind to about 2500 even when im driving easy, I have had converters with less flash stall that felt mushier

The converter dosent bother me. It's not my daily drver though. My trans is also set up for full manual operation. If I'm not into the gas 1st, & 2nd. gear feel about the same.

<font face="Arial,Verdana" size="2">Originally posted by JJZ28:
O.K. If you were turning 6800 with a 6" bottom, & 2,5"? top pulley I should be safe. I don't spin mine above 6000.
I still would like to know if Weiand states an rpm limit.
Mwilson, in answer to your question. I have run 12.31 @ 108 & change. I would really like an 11 something, though.</font>

Same here about 6000 2.5 pully on the top 6in on the bottom.. Very streetable with 3000 stall and 3:42......BUT you don't hear that whine, how about you guys, do you hear the whine? I talked to holley and I believe they said after 5800-6000 you heat the charge.

I run the largest 7" bottom pulley and the stock 3.08" top pulley on my 142. I set a self-imposed redline of 6000 RPMs. That would be, theoretically 13,636 RPMs at the blower.

The smallest top pulley for the 142 is 2.85". If you run the 7" bottom and 2.85" top pulleys you will be at 14,736 RPMs at the blower at 6000 engine RPMs. I would think that would be about the redline for it.

The similar Holley 144 has a different pulleys available for it and might be able to spin a bit higher, but probably not much.

On the Holley/Weiand website they list 2.5" pn. 90636. 2.66" pn 90534, & 2.86" pn 90358 upper pulleys for the 142.
I just wonder if jumping from the 3.07" to a 2.5" will be too radical. As in having to back my timing way off, or use race gas (which I refuse to do). I also run drag radials, don't want to blow the tires off at the hit.

<font face="Arial,Verdana" size="2">Originally posted by vegas1974z28:
BUT you don't hear that whine, how about you guys, do you hear the whine? I talked to holley and I believe they said after 5800-6000 you heat the charge.</font>

With the grooved V-belt, I doubt if you'll hear too much whine. On the cog belts, most of the whine is from air escaping from the cogs and the pulley.

Mine whines really loud when I get into it. It drowns out my 2 chamber Flows. http://www.nastyz28.com/ubb/smile.gif

You might hear a little whine from the synchro gears that keep the lobes in mesh, but mostly it only bellows when you smack the throttle open.

And yes, it drowns out my 2 chamber Flows quite easily, too.

Thanks to all for your input. On the "Whine" subject. Mine's pretty quiet at cruise. It makes some noise at part throttle, but is drowned out by exhaust at wot.

Nothing whines like a 6-71 http://www.nastyz28.com/ubb/smile.gif

http://memimage.cardomain.net/member_images/2/web/626000-626999/626471_21_full.jpg

Thanks for all the advice. I'm just gonna jump, & get the 2.5" pulley. If It's too much I can always go smaller.
Hey Damon, or anyone else. Do you have any tuning tips for the smaller pulley? I know I'll back the timing off, & jet up initially. But how far?

The 142 has a port on the lower intake that comes with the blower- it's there so you can screw in a boost gague line. BUY A BOOST GAGUE. Once you have the motor built and running take it out and see how much boost it's ACTUALLY making at WOT, with the engine tuned VERY conservatively. With stock bower pulleys on a modest 383 or 400 you will probably see very little boost- 3 PSI or so. When you install the smaller top pulley you will probably be up around 5 PSI. You want to be around 5-6 PSI of ACTUAL OBSERVED INTAKE BOOST for a reasonably power-producing starting point. Tuning from that point depends on basically 3 things:

1. Your compression ratio. Anything over 8.5:1 and you'll be "walking the tightope" like I am now with my engine.

2. Ignition timing. The lower your compression, the more you can dial in. at 8.7:1 and 5 PSI I run 26-28* total timing.

3. Similar to nitrous..... never EVER run lean. Mid 12s for A/F ratio if you're running a carb. You can play on the bleeding edge (little leaner) if your compression is lower, but that's about as scary as I want to get on my combo, personally.

Then, if you like, you can start going with more boost and keep repeating the tuning process between the spark timing and A/F ratio. Just go up in steps, incrementally, testing and trying different stuff as you go.

Like I said, if I had it to do over again (or if I was building my first blower engine) I would drop compression down to around 8:1 and not live on the bleeding edge as I am doing now with the tuning.

Damon, thanks. I do have a boost gauge. I was seeing just under 5lb. of boost through the lights at 5500rpm. I had 1 5/8" headers, I have since put on 1 3/4". I think this will free up some hp. My compression is around 8.3:1. KB 142 pistons, 72 cc. Iron Eagles.
I'm looking forward to seeing what upping the boost will do.
Thanks.