Results with WI on a V-8 w/Roots blower?
 

Anyone here using WI with a Roots blower? I have a 5.7L Chevy V-8 with a Weiand supercharger, thinking seriously about adding WI but would like to get some opinions and hopefully results before going to the trouble. I just finished tuning the set up and have noticed a strong correlation between air temps and apparent power production. On cool mornings or just after I set out on the road, it runs very well but on hot days and after running it begins to sag. I suspect this is due to charge heating, despite the air intake hanging out the hood in the slipstream. I need to add a manifold temp gauge to confirm this (drilled/tapped a hole for one) but I have to believe ADI is needed. Also, is a fixed jet system adequate? I plan on piecing together a system from CoolingMist unless I hear to the contrary. Does anyone know what the ADI system looked like on the WW2 aircraft engines? Wonder if it was a simple on/off or if it was demand metered.

Re: Results with WI on a V-8 w/Roots blower?
 

Not sure about the ADI or CoolingMist systems, but that Roots blower is definitely not helping your air temps. If the boost is higher than 5 psi I think the temps are too high due to blower efficiency.

I am running a Eaton 112 hybrid roots.are you running carb or FI,do you plan on spraying into the s/c or after it?I saw a really cool setup on this forum from a guy who made a plate under his eaton s/c.I am new to WI but I am spraying through the s/c just before the TB.also I think that intercoolers are now available for the 6v71 style roots s/c.either way,IMO WI would definately help your situation.

I'm running EFI on my supercharged combo, but I've built some potent carbd combos too. Regardless, I wouldn't spray water before the blower. The mist will most certainly eventually corrode the rotors and destroy the teflon seals, if equipped. WI on positive displacement blowers is most certainly a post-discharge thing.

I had reservations about setting up my WI before the s/c.The reason I thought it would be ok is because of the setups I see with the carbs on top of the supercharger and I thought since the fuel (gas and alchohol in dragsters)passed through the s/c in those setups that my setup would not cause any harm.I also liked the idea of the cooler air going through the intercooler that is under the blower.I have only had this installed for about a week.A guy with a GTP on this forum has a plate under his eaton fabbed for the WI that looks really cool.BTW I will also be spraying a 100 wet shot of nitrous through the s/c.Are you sure that the way I have this setup isnt good?Thanks for the heads up--JA

I'm sure that spraying before the blower will work, but durability will be suspect. The compressor should really only be compressing air, nothing else, IMHO.

I have a few thosand miles on the setup now and all seems well.A combination af NYC traffic and numerous blasts and top end runs.I would like to take a look inside the s/c but that is too much work.I have been putting an average of 3/4 gallon through the s/c per day.If there is going to be a problem,I'll find it!I put about 700 miles/week on the car.

Quite a few folks in the Miata community that're running 1.2L Whipples and MP62 'chargers using pre- and post-'charger WI quite effectively.

While both pre- and post-charger WI will effectively facilitate power production, pre-charger WI will degrade rotor integrity over time. Pre-charger WI will not be as durable a post-charger WI. It may be negligible, however, considering that the WI only kicks in under heavy throttle.

One guy who is/was running a custom MP62 'charger on his Miata called Magnuson to ask a few questions. This, and the max blower RPM were a couple of the questions he asked and was told pre-blower injection had a negligible effect and above 20-21k RPM was when things would start to come apart on the blower: he had been running 22k RPM for quite some time :)

I've got an expensive billet cased twin screw unit and I know how much it costs to rebuild the rotors. The Roots types are considerably cheaper, so it's understandable.

Why not call up the company that produces your supercharger and ask? I can't imagine water alone would have any effect on the rotor coatings.

well--I'm doing pretty good with the setup,I've brought intake temps down about 40 degrees and the car pulls strong.I started with about 550 RWHP before the install and I'll have to dyno once I decide what preassure/nozzle to run,as well as water/alky ratio.This is one of the most interesting things(Alky injection) I have come across in my 20+ years of building.I have alot of questions and theories to work out.I've decided that since Magnusun runs a carb on top of the supercharger,allowing the air/fuel mix through it then I can run the water/meth.I will get to really put alky injection to the test in the summer in NYC traffic.If anyone has any suggestion or experience to share please do---