blow off valve?

[dieselpower]

ok i kno what your thinking,
whats this kid doing wanting to put a blowoff valve on his car like the ricers do. well i have quite the turbo lag from a stop so i was wondering if this would be worth doing. i have an air idle stabalizer or whatever they are called and want to hook it up to where the stock blowoff is. i'd remove the insides of the stock one so it just blows through all the time then hook up the valve to an arming switch and a switch on the clutch.

so when im at the tree waiting for it to turn green, i have the clutch in and the valve is open. then because there is no load on the turbo when i rev up the engine the turbo also spools up with no boost but just gets spinning. then when i drop the clutch the valve closes and the already spooled up turbo makes boost...does anyone see any problems with my theory? because i dont really want to waste all that time doin this just for it not to make any difference or to break sumthing.
thanks for the help

mark

[Dr. Diesel]

Don't waste your time.  :lol:

Blow off valves prevent compressor stall while shifting gears, on cars with throttle valves.

To build boost on the line, you need to load the engine. Slipping the clutch with the brakes on will work, or throttle and brake with an auto trans.  I've personally found that I can almost eliminate lag with launch technique. Nitrous makes it go away very quickly too.

[VWRacer]

Not to worry, Mark, it's a fair question. But like the good Doctor says, a BOV of the type you're talking about won't help a diesel engine.

OTOH, from the sounds of it, I would suspect that either the boost relief valve on the intake manifold or the wastegate may be opening prematurely. Have you checked them out? Also, my Quantum didn't have a boost gauge, so at first I couldn't tell exactly when the engine was making boost and how much it was making. Buying a simple boost gauge was a real eye opener, and helped me find what was wrong with my engine (knackered compressor).

[dieselpower]

i blocked off the boost releif vavle so thats not the problem. i don't kno how to test out the wastegate tho to see if it is working properly. Im running 20psi of boost using a low pressure rgualtor along the line. how long does it take you for your turbo to spool up. because before i removed the gevenor i would have to go thro a whole gear before it would build full boost at 15psi accelerating from 1st or 2nd gear. im not sure if thats just how they are or if my turbo's messed up.
thanks for stopping me from wasting my time. haha.

mark

[andy2]

I,ve been wondering about 1st gear turbo lag myself, and was thinking of driving the turbo at idle in first gear with an A/C 110v high rpm motor.The K24 has a 12point nut on the compressor side that could  be coupled to a 12 point socket that would pivot with a solinoid in and out to drive the beast there is other details,but thats about it.This could be a waste of time and as mentioned there are easier ways around this lag :x . I have two reasons for doing this;It would be cool to improve acceleration without reving too much and it could help with eleminating most of the off boost smoke which I'am always bothered with. i'm not expecting crazy boost at idle ,only to jump start the the turbo when idling. any thoughts :idea:

[QuickTD]

I,ve been wondering about 1st gear turbo lag myself, and was thinking of driving the turbo at idle in first gear with an A/C 110v high rpm motor.

High rpm wouldn't adequately describe the motor you would need. Being in the automation biz, I deal with all types of motors, DC brush and brushless, switched reluctance, AC induction and flux vector. There are no off the shelf motors/drives that fit the bill. You need at least 80000rpm and probably upwards of 15hp to drive the turbo. The power to drive the turbo compressor at full honk often equals the crankshaft hp of the engine! There are plenty of air motors that pack this kind of punch in very small packages, one of them is the turbocharger turbine itself, food for thought.

 I believe 3k warner is working on an electric anti-lag device. It uses a permanent magnet brushless DC motor and a purpose built electronic drive. From the notes that I have read it can draw over 1000 amps from the battery when used as an anti-lag device. It can only sustain this power level for a few seconds due to the thermal limits of the windings. The rotor of the motor is an integral part of the turbine/compressor shaft and the whole unit is only slightly larger than a normal turbo. Cool stuff...

Meantime, the cure for lag is the KKK K03-003, shame about its high speed/flow performance. We may need to explore regulated 2 stage turbocharging...  [/quote]

[andy2]

wow,QuickTd it sounds like you have thought about these issues before. As Dr.D says its all about the launching technique that works well by the way.I supose that the 2 stage turbo deal would help both the 1.6/1.9 engines in that you've got more bottem end boost while I've got more top end boost so if such a system was made up it would be worth while making in case I moved up to the 1.9 :wink:

[SMOKEYDUB]

Well if it is all in the launching technique would you be kind enough to explain how you do it because it sucks not having much boost in 1st.

Thank you

Jeff

[fspGTD]

Lightened flywheel helps a lot too!  It gives the most help in the lower gears, and helps with launching / 1st gear more than it does with any other gear.  It makes the engine much more responsive for quick changes in RPMs.