Impeller speeds

[351wStang]

Ok, I have a Vortech S-trim with a max impeller speed rating or 50,000 rpms. Right now I have a 8" crank pulley and a 2.95" pulley on the charger. According to Vortech's calculator I will be hitting the max speed of my impeller at about 5,300 rpms. I'm running a F303 cam with Edelbrock RPM heads and was planning on spinning this motor up between 5500-6000 rpms. So, since I dont have an engine dyno and a bunch of 8 rib pulleys to swap on and off I'm not sure where my shift point will be. So I figured I would comprimise and shift at say... 5,700 rpms. I'm guess this would be a pretty good shift point. So at 5,700 rpms with my current pulleys my impeller will be hitting speeds of about 53,000+ rpms. I'd like this charger to last until I decide to upgrade. So.. I can swap to a smaller 7" crank pulley or a bigger blower pulley. I played around on Vortech's calculator and ended up with this. My 8" crank pulley and a 3.15" blower pulley at 5,700 rpms will be spinning my impeller up to about 49,950 rpms.

What do you guys think? Am I cutting it too close? I know 1 good over-rev would send my impeller to the moon. Am I going in the wrong direction here? Any other option or advice? With my current pulleys Vortech told me I would probably see around 12-13 psi at about 6,000 rpms. Now with a bigger/slower pulley on my supercharger what kind of boost do you think I will see? 10lbs? Thanks in advance for the advice!

[hustler8225]

have no clue!

[351wStang]

Well for those interested, I was told at the corral that I would be fine with the pulleys I've got. They said that I could spin higher than vortech's 50,000 rpm rating without issue. Also once you consider belt slip (8 rib) I should be in the safe zone. With 0 slippage at 6000 rpms I would see about 56,000 rpms with my current pulleys. Even after belt slippage if I over spin the impeller it will only see those really high rpms for a fraction of a second.

[351wStang]

Originally Posted by hustler8225

have no clue!

Dont post if this is the only kind of thing you have to say. I saw a similiar post of yours in another thread. However, thanks for the bump.

[Simioh]

LMFAO!!! yeah, he posted the same bs on my thread, its funny, i guess he has nothin better to do

[SkylineUSA]

Look at those head lights on your car, need to polish them up

On my old Stang, I had the same pulley set up, she will slip a little, but that is not the issue. The rating is more for the effcience of the charger, so you will just be making a little hotter intake charge, if my memoery serves me right. On ebay, they sell those bracket tensioners, you might invest in one of those.

[351wStang]

Originally Posted by SkylineUSA

Look at those head lights on your car, need to polish them up

On my old Stang, I had the same pulley set up, she will slip a little, but that is not the issue. The rating is more for the effcience of the charger, so you will just be making a little hotter intake charge, if my memoery serves me right. On ebay, they sell those bracket tensioners, you might invest in one of those.

Thanks for the reply Skyline. Ya I'm just gonna replace the headlights lol. As far as the intake temp goes, what do you think about a water injection kit? Also I'm still looking for brackets period. Several people have offered to sell me their front plate because they are upgrading. Should I just buy a bracket from Vortech with the 1/2" front plate from the start? Do you know if the mounting holes on the front plate are what need to be modified to lower the headunit on my 351? I'm thinking maybe just redrill the holes in the front plate where it bolts to the mounting bracket on the head. Also how was your altenator relocated? Thanks.

[SkylineUSA]

I really dont know the way to do a 351W, other than getting the plate, and putting it up to the 351w block, and start modding it. As for the Atl, my stang was already set up when I got it, so I am not sure what braket they used for that. If I still had my Stang, I could tell ya.

[351wStang]

Just bought a Vortech bracket assembly from a guy at the corral. It has an alt stay bracket or something like that on it. If all else fails I'll just mod my A/C bracket and put the tensioner between the alt and P/S pump going down the drivers side.