This product is applicable to all supercharged cars, regardless of manufacturer.

Add Safety and Performance to your Supercharger Installation!

Add Safety: Our new Boost Limiter Valve (BLV) increases your engine safety two ways: 1) a missed speed-shift or over-revved motor can spike boost pressures and blow inlet tubes, MAF and MAP sensors, and head gaskets. The BLV will open and prevent dangerous over-boosting and save buckets of $$ and headaches. 2) with a BLV, you can set the boost level to match the maximum fuel delivery you have to prevent dangerous engine detonation at high-boost points.

Add Performance: Imagine your centrifugal supercharger comes in now at 3500 rpm and your red-line is 6500 rpm. That's 3000 rpm's of useable boost. But now, with a BLV installed, you could change your drive pulleys to bring the boost in at 2500 rpm and simply bleed-off the over-boost at the top end. Now you have 4000 rpm's of useable boost!

Description: Expertly machined from 6061 aluminum billet, with a type 302 stainless steel spring, and a high-temp solid PTFE valve ball. A high-quality piece that will last for many years. Operating temperature range is -328° to +500° F. Has 7 large outlets - this model moves more than 4x more air than our previous 3/4" BLV model. One BLV will control one very large supercharger or two small ones. Can be polished.

Until now, the only solution for a supercharger install has been to purchase a turbo waste gate and a boost controller switch and modify them for this purpose. Usually about a $400 to $600 investment for these two parts - and then you have to see if you can make them work! The 928 Motorsports BLV is designed for this purpose, and does a better job in a smaller and more compact size than the waste-gate solution for this application.

Pre-Calibrated: When you order, you can tell us what to set the initial calibration to and we will set the BLV to that PSI for you before it ships. Select pressure range from 1-30 psi of adjustment, or 20 to 110 psi. The BLV can be easily adjusted at anytime. No special tools required.

Installation: Simply install in any tube between the supercharger and the MAF or MAP sensor. Usually installed near the BOV. Choose from a steel or aluminum weld bung when ordering. One weld bung is included with your BLV at no charge.

Benefits:

Bring your boost in earlier without making too much at redline.
Prevents over-boost, blown gaskets, detonation and engine damage.
Adds a level of safety for your supercharged motor.

Pricing and additional pictures are here:
http://www.928motorsports.com/parts/...mitervalve.php

 

Are those pipe threads or straight threads ?

 

they are 1" NPT, and we provide either a steel or an aluminum weld bug to match with each one.

 

What does it sound like when it's bleeding pressure. Interesting solution...

 

I'm sorry, but this sounds like a solution looking for a problem. Maybe I'm wrong...

 

It starts to chatter just as it is nearing the burst point, when run above that, it just sounds like a large rush of air - sorta like a unmuffled BOV going off.

We did Proof of Concept work on this invention by purchasing smaller valves made from brass and modifying them in-house to serve our purpose. We have a number of these installed on supercharged Ford Mustangs and in Australia, several boosted Holdens.

The owners love 'em, the only problem was that they needed two of them to handle the largest superchargers.

So we scaled up and now make our own from billet.

 

 

 

It's all the flows yo! Woo Woo!

I've used that same brass valve from Grainger to manipulate boost on another car.

 

So is this in essence a very large tire pressure relief valve? The one that some racers use to maintain constant tire pressure during a race?

 

If there was a real need for this (again, I'm not sure there is - not saying this is a bad product, just don't see the need) I would think someone running a boost application of less than 20psi, which is everyone I know of except for one person, could use this item # 48935K45 (bottom of page):

http://www.mcmaster.com/#catalog/114/458

Actually, this looks like what Carl used for his POC.

 

I have always just used a cheap BOV, not connected to the vaccum system and utilizing spring pressure and shims.

This would make adjustments easier! We use alot of them at this altitude because superchargers make less boost up here. We don't want them going crazy when customers take them to lower altitudes. George Suennen's V1-t makes almost 15psi at sea level and only 11 at ORR altitudes. The 15psi 89' I built with a V7-Ysi would be over 20psi at sea level and the engine is not built for that much boost.

 

Overboost is a very real concern on super or turbocharged engines. Wastegates fail or boost metering lines have come loose (BTDT) and the options aren't pretty. Porsche uses an overboost switch that cuts fuel but that has been known to bust noses on the steering wheel. The BOV concept is much better in that you don't loose all power when it activates and some folks think the sound is neat.

Dennis

 

Dave brings up an EXCELLENT point about the variable of altitude and the desirability of having a "fuse" a safety valve to limit boost. Having the BOV and driving the blower faster can bring in more POWER at lower RPM. That needs to be balanced against the waste of energy compressing air only to vent it to the atmosphere. But how much time does one spend at full throttle / high RPM ?? Tim and Cheryl being the exception

 

For this application, I can understand the need. I'm at 800' so a drop in altitude has never been a problem.