yamahaSHO gets blown! 56k.... not likely

[twr]

Here's a really good technical explaination from Gary from another forum regarding this subject.

(Zeptoplix @ Apr 16 2005, 11:35 AM)
Not really. The maf measures air in a vaccuum. not compressed air.. compressed air is more dense, well obviously... I dont see how it could get an accurate air measurement since its not designed for compressed air. The computer will compensate for the air you pull through the maf. not sre about pushing it through tho.

(gmorrell @ Apr 16 2005, 8:46pm)
No, MAF's measure mass flow; grams/second, kilograms/hour, pick your favorite unit, but its mass flow, and its independent of pressure and temperature. Mass flow is the same on the intake and discharge sides of a turbo or supercharger compressor. If it isn't, then there's a leak, or you've figured out how to violate several well-established Natural Laws.

For a hot-wire MAF meter, basically: I^2 = A + B sqrt(Ga)
sqrt = square root
Where I is the hot wire heating current,
A and B are constants relating to physical properties of air and the MAF design,
Ga is the mass flow rate.

 

[SHOMurph]

You lost me at hello.

If its proven I'll do it! I'm having TexanTony rebuild the motor anyway.

Actually that makes it easier. I'm looking at PWR's barrel type of intercooler. It will fit right were the MAF use to be with a little tube cutting.

Instead of re-routing the blow off vent.....can we do like Josh did and just put a blocking plate on?

 

[AutoSHO]

I think I would leave the BOV in place and plumb it back in.

Josh can run a blockoff plate because he has his throttle body pre-blower, so the piping is never subject to ovepressurization.

 

[ArkanSHO]

You lost me at hello.
If its proven I'll do it! I'm having TexanTony rebuild the motor anyway.
Actually that makes it easier. I'm looking at PWR's barrel type of intercooler. It will fit right were the MAF use to be with a little tube cutting.
Instead of re-routing the blow off vent.....can we do like Josh did and just put a blocking plate on?

Putting a blocking plate on it means your boostis only limited be the diameter of the pulley. ANd also as discussed previously there is the issue of the pressure building up rapidly when the throttle plate snaps closed (though that helps me find the hose clamps I didn't have tight enough) backpressuring the blower itself. I like the PRW unit. Have I posted this pic before? Not a good pic to show the routing of my BOV, not that it would even apply to the way a V-6 is plummed in any case.

 

[Lupo]

Yes, something like that... Although, I am still curious why you vent yours back since your MAF is after the blower? Did you have someone fabricate that for you? Do you have a picture from the other side?

It an easy fabrication. Just get the tubing in straight and bent pieces, and piece together the pipe by cutting and tach-welding pieces. Same process for making custom exhaust. I got a good welder to actually finish up the complete weld. Then, you can grind the welds smooth, and paint or powder-coat.

I have it that way for 2 reasons:

1. I am using the inlet side of the S/C to work my pcv system with a catch can. If I let my BOV vent to the engine bay, I smell exhaust anytime my climate control is on, and the car is stopped at a light. Esentially the climate control is sucking in the fumes from the engine bay.

2. One day, I might actually put my MAF before the blower!

 

[yamahaSHO]

I have said it before, but I will say it again. You have done an awesome job with the car.

How and where did you locate the two stage water injection? Are you running 100% water or water/alchohol?

Thanks again for you help. The only problem with your car, is We keep having "technology transfer" over to our cars (water injection, soon to be knock sensor, etc). You are making us go broke. At least we are going broke fast (speed that is).

- Mike

Mike, I have not connected the water injection yet. I've fabricated a mount for both solenoids and will mount it near the remote/bypass oil filters. The pump will be mounted in the fender and thanks to PanamaPat, I've a stock windshield washer bottle that has been cut and plastic welded to fit on the oppsite side. I'll be drawing water and/or windshield washer fluid from there and injecting it via two nozzles in the section where SHO Shop mounts the MAF.

I guess I won't tell you about the remote/bypass and the Accusump

It an easy fabrication. Just get the tubing in straight and bent pieces, and piece together the pipe by cutting and tach-welding pieces. Same process for making custom exhaust. I got a good welder to actually finish up the complete weld. Then, you can grind the welds smooth, and paint or powder-coat.

I have it that way for 2 reasons:

1. I am using the inlet side of the S/C to work my pcv system with a catch can. If I let my BOV vent to the engine bay, I smell exhaust anytime my climate control is on, and the car is stopped at a light. Esentially the climate control is sucking in the fumes from the engine bay.

2. One day, I might actually put my MAF before the blower!

Understood. Did you ever think about routing your PCV out to the exhaust?

 

[bobreimer]

I just installed the same setup (and had some of the same issues no doubt). Don't forget to vent the crankcase to atmosphere. I didn't at first and oil was oozing out everywhere. Its common sense I guess, but it still took me a while to "get it".

I'd be interested to know how your charge cooling system works.

Also, I didn't vent the BOV back into the intake. Just put a little filter on the end of it. I guess it would be a little quieter if it released back into the intake.

Bob

 

[SuperchargedSHOguy]

Don't use the filter on the BOV...It is not necessary. Under very high boost, I actually blew mine off and removed it for good since it was deemed a restriction.

 

[yamahaSHO]

I just installed the same setup (and had some of the same issues no doubt). Don't forget to vent the crankcase to atmosphere. I didn't at first and oil was oozing out everywhere. Its common sense I guess, but it still took me a while to "get it".

I'd be interested to know how your charge cooling system works.

Also, I didn't vent the BOV back into the intake. Just put a little filter on the end of it. I guess it would be a little quieter if it released back into the intake.

Bob

WAAYYYY ahead of you on the PCV. I've had mine routed through the exhaust for at least a year now. I would check your front an main seals to be sure you did not blow them out... We had a guy here in CO build up a blower car and forget to vent the crankase to somewhere other than the pressurized intake. He blew out his seals.

For charge cooling, you can find more at www.coolingmist.com.

Don't use the filter on the BOV...It is not necessary. Under very high boost, I actually blew mine off and removed it for good since it was deemed a restriction.

He can run if it he so chooses. You're doing something wrong if you blew it off. 17lbs of boost on PanamaPat's race SHO and no problems with the filter on the BOV. A small K&N filter is far from a restriction. The real restriction is the smaller opening of the ****** on the SHO Shop piping.

 

[SuperchargedSHOguy]

He can run if it he so chooses. You're doing something wrong if you blew it off. 17lbs of boost on PanamaPat's race SHO and no problems with the filter on the BOV. A small K&N filter is far from a restriction. The real restriction is the smaller opening of the ****** on the SHO Shop piping.

I put back on a 3.1 pulley. I don't want to blow the tranny apart right now. I was running one a couple sizes smaller when I blew mine off hitting higher than 17 psi. This was also in my old stock diffed tranny. What could I have possible done wrong to blow the filter off please explain...

 

[yamahaSHO]

Crank the clamp down tighter. If you talk to Josh, the ****** that SS uses is not large enough. That would be more of a restriction the K&N "dirt" filter (as in it filter the air out of the dirt ;-)

More than 17PSI is more than I've seen on built SHO motor. Are you making any more power than that dyno you posted before?

 

[SuperchargedSHOguy]

The motor is low compression and I did a few runs with a 2.87 pulley for fun (lucky the tranny/compressor held together).

That dyno was not good numbers to go by. Many people who did dyno there had low #'s like myself and complained. That dyno has since been "recalibrated" and I know a couple people that have dynoed there again and were much happier with the accuracy now. Also, the guy that dynoed my car did not hit full boost. He said he saw the smoke (rich) from the tailpipes and thought she was gonna blow and did not keep her to the floor. There were a few other minor issues with the car that day that have since been fixed.

The car needs charge cooling which I am in the process of fixing and the SS piping is going to entirely get "re-engineered" (buh bye SS ****** as well as some other things)


Back to the post...your car looks great with the s/c under the hood. I can't wait to see the numbers, especially with your water injection

 

[Lupo]

Understood. Did you ever think about routing your PCV out to the exhaust?

Yep, you read my mind. That is next on the list for me.
Do you have a picture of where you welding in the bung?

 

[yamahaSHO]

How's this?

Terry put his in a different spot than I did, but I plan to do my '92 in this manner as well.

 

[ArkanSHO]

Not real sure how long that rubber tube is going to last being that close to the cats.

 

[yamahaSHO]

It hardens up and stays in place (the bottom few inches anyway).... I have to replace the hose everytime I take it off, but it is cheap to replace.

 

[twr]

Here's another picture of the same system Jason has, but I had it welded in where my exhaust goes to 3". FYI My flex pipe is welded to the y-pipe.

 

[Lupo]

Here's another picture of the same system Jason has, but I had it welded in where my exhaust goes to 3". FYI My flex pipe is welded to the y-pipe.
[/IMG]

Are both your PCV lines hooked to that bung? You have the one form the valve cover, and the one from the engine block valley. Are they teed, or does one have a breather?

 

[twr]

Are both your PCV lines hooked to that bung? You have the one form the valve cover, and the one from the engine block valley. Are they teed, or does one have a breather?

The valve cover line has a breather on it.

 

[yamahaSHO]

To add to what Terry has said, the valve cover is used as a fresh air intake, even in stock form. When using the crank case evacuation kit, you'll run the PCV from the oil seperator into the exhaust utilizing a one-way check valve. The valve cover has a filter on it, but I have used a socket to connect it to the hose to limit the amount of air that is sucked in to keep most of the blow-by flowing through the exhaust instead of just sucking fresh air into the block and out of the exhaust. In normally aspirated applications, you do not want to connect the VC to the TB when using the crank case evacuation kit because you'll be pumping metered air into the block, then out of the exhaust.

In addition, when it comes time to pass emissions, you can disconnect the oil seperator and suck fresh air through the exhaust.