Can the Vortech S trim handle 20psi of boost? I thought it was rated up to somewhere around there. I am getting a hell of a deal on a whole setup and plan on building a motor that can take this kind of boost. Let me know. Thanks, Jarred

 

Straight cut spur gear

Fits engines up to 680 horsepower

Maximum airflow: 1,000 CFM

Maximum boost pressure: 20 PSI

Maximum impeller speed: 50,000 RPM

Adiabatic efficiency: 72%

Available with straight or curved discharge and clockwise or counterclockwise rotation

I answered my own ?

 

Well, according to ATI, my old P600B would do 24# of boost. There's no way in hell that's possible in the real world. 15, maybe 18, but not 24.

 

There's a difference between the max boost the blower is capable of against high resistance and what it actually produces when hooked up to a running motor. Kind of like comparing the pressure a fuel pump makes when it is against a closed pipe ("dead headed" ) versus the pressure it produces when hooked up to a fuel system.

Not sure if I am making this clear, but the point is that the max presure for a given compressor is not an indication of how much boost it will make on a motor. The CFM rating is a better reflection of max boost. On a typical 383, an S-trim or comparable blower (P600) will max out at 12-15psi. On my combo, I got 13-14psi from an S-trim (1,000CFM). With the Procharger F1 (1,525CFM) I see up to 21psi.

Rich Krause

 

So you don't think with a big enought bottom pulley and small enough top pulley I can near the 20 pound mark? How close could I expect to to get the S trim. Thanks, Jarred

 

Depends on your motor. The larger the displacement and the better the head flow, the less boost (but the more hp) that you will see. It's airflow, not manifold pressure, that makes hp. Think about a 2L 4cyl with a 20psi blower and a 383 V-8 with 20psi. Which makes more hp?

Rich Krause

 

In a word: No.

I'm using Vortech's largest crank pulley (6.66") and smallest blower pulley (2.75") on the larger T-trim and am seeing around 13 - 14 psi boost.

ASP makes a 7.00"/2.5" combo that would do around 15 psi, again, with the larger T-trim.

Mike

 

Mike, do you think I even could if I stuck with stock heads and just went with a blower cam. I would just upgrade valves, springs, etc. and maybe do 1.6's. I just want to know the best way to make loads of boost. Thanks, Jarred

Also if I have a S trim could I just buy the T trim later and swap it out right into place? Thanks, Jarred

 

Perhaps I didn't understand the goal, but I think I got it now. . .

You want a high number to show up on the boost guage, but you're not worried at all about the number that shows up on the Dyno or the ET/MPH at the drag strip, right?

That being the case, leave the stock heads, stock cam, stock exhaust, and remove all of the driver's side rocker arms from the engine. You will make in excess of 20 psi boost in that condition.

You see, what Rich tried explaining earlier is that the more air your engine flows, the less boost pressure you have, but the more power you will make. If you build a stroker, you will lose 1 psi boost, but make more hp. Same goes for ported heads, bigger cam, etc. . .

Why are you worried about the boost number when the power number is what really counts?

Also, in order to run 20 psi boost, you would need to lower the compression to around 8/1, install an all-forged rotating assembly/4 bolt mains, install an exotic fuel system, extensive programming or FAST/DFI computer, etc. . .

Yes. The only difference is the T-trim has a 3.75" inlet versus the 3.5" inlet on the S-trim. You need a larger hose to connect the inlet piping.

Mike

 

No Mike I understand about how the higher the CFM and lower boost I will make more power. If that is right? I just wondered what it would take to make 20psi is all. I plan on doing a fully forged 355 with like 8.5:1 compression. I thought with a good blower cam I could expect some pretty decent amounts of boost but I am understand what you are saying too. I don't think I would be able to afford the heads for a while is all. Thanks, Jarred

 

If you do the following, you could get maybe 16 psi effectively with an S-trim:

- 8.5/1 all-forged 350

- stock heads/good valve job/cleanup work

- blower cam (doesn't add boost, BTW)

- headers/good exhaust

- S-trim with 6.66/2.75 pullies

- aftercooler (a MUST to keep it from breaking)

- twin in-tank 255 lph pumps, one triggered by a boost switch

- either a Versafueler and large, low-impedence injectors, or some 42 lb/hr injectors and a Superfueler (I'm selling one right now, BTW).

- MSD or Crane ignition amplifier

- extensive programming/dyno tuning

Mike

 

Like Mike said, you can make a big number with a relatively small blower if the motor doesn't breathe well. If you have stock heads and a relatively small cam, you may see 20psi. However, also as Mike said, you will need stout bottom end parts and a low CR if you plan to max out the blower, whatever the boost it finally makes.

Rich Krause

 

 

Be prepared to spend alot of time with a Wide Band O2 sensor and some sort of scanner when programming.

Mike

 

I hear ya there. Luckily my buddy can tune it for free for me and I am just gonna rent the dyno for like an hour so we can get some tuning in. This will be a ways off like next summer. For now I am just gonna bolt up the S/C kit and go. I am only 17 so I figure I am doing alright with a blown LT1 and then major motor is in the works. I have to fund it all so it helps to have friends that can help me out bigtime. Later, Jarred