Super Charger on Taurus SHO no power, other probs.

grey500se

Registered User
first of all, I know many people may think this is crazy but lets just get down to the help

94 SHO, I mounted the Supercharger (SC) M90, which was tested before mounting, I'm not running an intercooler, it is mounted where the AC used to be side ways (basically 90 degrees clockwise from a regular Tbird SC) , I have the inlet plenum, the stock top, from the pressure side, a t-connection to the bypass side, and then to the throttle body of the SHO engine, I have the stock tbird Throttle body hooked onto the inlet plenum (like the regular tibird), the SHO MAF sensor to the SC thottle body, a cable that opens the TB connected to the SHO throttle body


the car runs fine at idle, when I take it on the road, I'm getting 2-3 pounds of boost, and their is a lot less power than it used to be even with no load, I think it has something to do with the bypass valve, I can't figure out if I have the correct vacuum line on it, the vacuum goes from the bypass actuator to the intake of the SHO engine, any ideas?
 
First thought is that it is probably lean. What size injectors, fuel pump, MAF, etc?

Next thought is that without the intercooler the air charge is going to be pretty hot and it may be pinging, especially if it is lean. This'll get the knock sensor in the act which'll absolutely kill the power.

And another thing, don't the SHO's pull like 8 grand or something? Have you calculated the top supercharger speed for the way you have it pullied. I think they go boom much over 16K rpm. The point is that you may have a spot of difficulty pullying for decent boost until way late in the powerband.

edit: I just caught on that you have the TB after the SC and bypass tube. If you look at theoriginal install you'll find that the TB is before the SC. What you've got happening now is the SC is stacking boost on the closed throttle and making it very hot. Get that TB on the inlet side of the SC first.
 
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thanks for the reply, the boost I'm getting is at 3-4000 rpm,stock injectors, I don't really want to run too much boost, 5-6 pounds if possible, MAF is stock as well, it does ping with the boost it gets but shouldn't the timing retard actually help in boost situations?
 
Well, even 5-6 lbs is enough to need extra fuel. So you'll either need larger injectors and calibrated MAF, or goof around with a FMU, either way works.

AS far as the timing retard the idea is to tune so that you don't need it except to cover unanticipated conditions. The timing map of the N/A SHO will be completely wrong for a boosted application. Probalby going to need a TwEECer or other similar type computer tuner device.

BTW, don't miss my edit on the first post. I feel it's important.
 
noticed the edit, I think, thanks for the help so far, what about the bypass valve vacuum hose, where is that suppose to go? I have it on the intake of the SHO engine, is that right?
 
The bypass tube is supposed to tap into the intake tract between the TB and the SC inlet. It then connects to the intake tract after the SC. This allows the intake air to bypass the SC. The valve is normally closed and manifold vacuum pulls it open. This allows the air to bypass that SC when vacuum is high (light load) and then when vacuum approaches ambient pressure the valve closes and the air path is now through the SC creating boost.

There, clear as mud? :)
 
Well, when you get that TB out in front of the SC inlet you'll be putting the bypass valve control vacuum hose somewhere between the TB and the SC inlet.
 
one other bid problem I have is oil vapor is shooting out of the PCV pipe of the valve cover during boost, do you think my rings have gone bad, could their be that much blow by? I am driving the car now with the SC disconnected and I don't notice anything, if my rings are bad, then this whole project is a waste, the doesn't have a PCV system, the hose from the valve cover goes to the intake
 
Nah, I haven't done a Roots-to-SHO conversion before. These are just the typical issues that you get with any addtion of forced induction to N/A engines.

The 24's are probably borderline at first thought. I haven't done any calculations or anything. Ford started with 30's at first and the later SuperCoupes went to 36's. I would think you would likely end up in about the same place.

The oil vapor is probably from boost entering the crankcase from the intake though the PCV system. This has long been an issue with forced induction Fords. The older Turbo Coupes used a particular PCV valve (PV-127) and you strayed from the Motorcraft part at your peril. Same issue with the SC's. If the thing has a typical PCV system you'll probalby want to try either the Motorcraft PV-127 or the Motorcraft part for the SC's. Aftermarket PCV's don't work in these apps.
 
Sorry I thought I made it clear.

It is the valve itself that is different internally. It will seal agaisnt boost pressure where regular PCV's will not.

The remainder of the PCV system on the 'Bird is pretty standard. Fresh air inlet in one side, with a PCV valve connected to a central plenum of the intake on the other.

What the SHO has I'm not entirely sure. It could be a conventional system like cars have had since the Sixties, or it could be a metering orifice in a tube or something else.
 
You need to post a picture of that setup...Teh blower is probably drawing more HP thenits making you at taht boost level..If your running direct of crank thats why yer boost levels are so low
 
sorry I didn't take a picture, its mounted where the AC compressor was at a 90 degree angle, right now I don't have the belt on, just driving the car
 
There are a few SHOs with SCs and turbos of various types, and with various engines. Have you posted in the SHO club forums and looked at thier set ups?
 
Parker Dean said:
Nah, I haven't done a Roots-to-SHO conversion before. These are just the typical issues that you get with any addtion of forced induction to N/A engines.

The 24's are probably borderline at first thought. I haven't done any calculations or anything. Ford started with 30's at first and the later SuperCoupes went to 36's. I would think you would likely end up in about the same place.

The oil vapor is probably from boost entering the crankcase from the intake though the PCV system. This has long been an issue with forced induction Fords. The older Turbo Coupes used a particular PCV valve (PV-127) and you strayed from the Motorcraft part at your peril. Same issue with the SC's. If the thing has a typical PCV system you'll probalby want to try either the Motorcraft PV-127 or the Motorcraft part for the SC's. Aftermarket PCV's don't work in these apps.


The leakage comes through blowby from the piston rings, and is more common on boosted engines. If you look at the PCV system you will see that the PCV valve is on the suction side of the system (between the TB and blower). This is where the vapors from the engine crankcase enter into the engine to be burned. The inlet side of the PCV system is located after the MAF sensor and before the TB.

Make you have the system piped correctly. Having the correct PCV helps as well.

There is a lot of misinformation about how the PCV system works but if you look you will see what is going on.

Jeff

Jeff
 
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update

got a 47 pound injectors, 255lph fuel pump, car is now running way way too rich! got an SHOtuner RT on the way, will be here in Janruary

PS-do have plenty of boost!
 
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