Hi there

I drive an EVO VIII MR and am thinking about installing a WMI. My goal would be to really help spool-up. Now for that I guess placing the nozzle right befor the turbos inlet would be best to keep heat low where it is actually generated.

Now can anybody give me their own experiances with this layout? I know there are a lot of reports of wearing blades etc. But has anybody here really done that?

If yes, what where the results in

• Spool-up
• Performance
• Impeller-wear

Some of the new systems use a progressive injection parallel to the signal of the fuel injections duty cycle. This would basicly make it possible to place the nozzle right behind the IC and start WMI progressivly from a low duty cycle or low boost which would then probably also help spool-up by intercooling the load, especially using high methanal rates.
Can anybody give me their experiances on that layout concerning:

• Spool-up
• Performance

Thanks a lot for the information and best regards!
Kunz

 

Placing a nozzle prior to compressor would do the opposite. If you want spool then use a diverter valve known to hold boost and use a WGA with very stiff tension. This with stock IC/plumbing should give you all the spool your OEM turbo can tolerate - like 30 psi in a second. Also keep it lean during spool to make it crank out some more energy

 

on the stock metal DV, how are ppl pressure testing them?

apply pressure from under the poppet and top of the valve

OR

only apply pressure under the poppet?

 

I use the pressure under the poppet and on top of the valve. I found out when you remove the hose from the top the valve will leak at about 5 psi, and that was when the valve was brand new. With the top hooked up as well I can test to 29psi with no leaks on the valve. The pressure on the top of the valve helps hold it closed during boost.

 

the internal spring adds several lbs to what the top and under poppet sees, keeping the DV shut

a lot of test are just done with pressure applied only to under poppet

 

liquid impingement will spell disaster for an impeller spinning 100,000 rpm's. Even a mist will be bad, bad, bad.

 

Dont know about the MR valve but the plastic VIII valve beneath the diaghram is a small channel that feels the boost side. This, along with the pressure on the "poppet" is designed to allow taper and drivability. To test the holding capacity you got to apply air to the top of the diaghram at the nipple. It will eventyaly leak however because air will eventually fill under the the diaghram through the internal channel. For this reason I blocked the channel and stuck my own nipple in there and used a solenoid controlled via EcuFlash to make that sucker hold solid, but only when needed

 

You will also tear up the bearings in the turbo. The turbo will thrust towards the inlet port when spooling up because of the "vacuum" effect. When you "hit" the compressor wheel with water or any other liquid you will cause it to thrust quickly the other direction and it will cause premature bearing failure.

 

Thanks for the fast replies!

The spool-up of my turbo is already very fast at low temperatures due to the way I control boost. Also because of mapping ignition and fueling like said obove to get hot exhaust gases during this short period. What I really need then is the coolest load possible and hot exhaust gases...
Now what I want to do is get already cooler and denser air into and in the compressor. I made good experiances with WMI in my old 323 GT-R some 6 years back placed right after the IC concerning power and torque but couldnt really see a difference in spool-up time at high temperatures.

Unfortunatelly up to now I only hear the downsides of injecting befor the turbo...

By the way, the MR has a stronger Blow-off made of metal...

Kunz

 

the point of water/alky injection is to cool the charge air going into the manifold, make it more dense so you can add more fuel and make more power. It only makes sense to spray this after the intercooler. If you spray it before the turbo/intercooler, you are lessening the heat the intercooler can remove because you lower the difference between ambient temperature and the turbo outlet temperature. Taking it to an extreme example, at low boost (like the turbo spooling) the turbo won't be putting that much heat into the charge air, but the water/alky could be pulling out more heat than the turbo is putting in. The charge air after the intercooler could actually be lower than ambient, and the intercooler would then serve as an interheater.

Couple this with potential turbo damage, and I just don't see it being a good idea. You may make more boost sooner, but it won't be making more power.

 

duddle, I am absolutly with you up to a certain point. I still suppose the gain would still be higher than the potential lost. Sure, the IC'c efficency will be lower due to the reasons you mentioned and if there really should be blade wear...

Anyway the longer I think about it, the more I tend to place the nozzle right after the IC and use a progressive system starting at low boost / duty cycle injecting relativly high percentage of methanol which has by far not the cooling potential of water but vaporises much earlier, which ist needed for a max IC-effect and therefor a fast spool-up. Still the water will reach the combustion chamber and will do it's work there...

 

Don't do that!!!!
Just imagine the weight of a water drip arriving on your turbo trim rotating @ 180,000 RPM!!!!!
It's a bad idea, go after the intercooler where the air is hot and need to be cooled!
Injecting before IC will condense water into it...

 

some interesting read about PTI:

https://www.evolutionm.net/forums/sh...&highlight=PTI

 

I know someone in Australia using PTI for years and he was not put off by the wear. He treats compressor wheel as consumables. Benefits out-weight the cost of replacement.

Slowcar's link to Evotio's experiment have some interesting results. The effect was so noticeable that this should be looked into deeper. He was only injecting no more then 50-60cc/minute.

 

Kind of off topic here but this is a good abstract from MIT using alcohol as a direct injection petrol hybrid.

http://lfee.mit.edu/public/LFEE%202006-01%20RP.pdf