Hello all. I am new to the Evo scene but not new to high hp. I have also searched with no avail! Here goes......I am running 400awhp to the ground and storing my Evo for the winter. However, when the weather permits I will be driving her. My boost is at 25 and E85 is the fuel of choice here. I have talked to a couple of locals who drive there cars year round and they are putting out about the same hp. Both of these guys turn the boost down to 12-15 in the winter. what do you all think on this matter. Worried about spiking I guess. Oh and by the way I am in Minnesota if you have not figured that out Thanks in advance, Rick

 

Turning down the boost that far is pointless. You have to adjust your boost controller slightly to compensate for the cooler air temps and possibly lower quality gas (E85 changes to E70 in the winter) but that's it. Nobody who knows what they're doing would do what you mentioned

 

Ok. so what would your recommendation be>? Turn it down to say 22-23 from 25 or lower? Thanks for your input. Rick

 

25psi is perfectly fine for E70 so you're set assuming you have a good tune. Who tuned you? You will have to turn your boost controller down the equivalent to a few psi to maintain 25 though since the air temps are getting cooler.

I personally run 24-26 psi year-round on BP 93-octane.

 

Ron at RS Motors tuned her. And I have a switch installed to go right back to reg gas. But I lose 68 whp with the flip of a switch So I prefer the E85 (E70)

 

Oh thats right, I think I saw your post on EvoMN.

 

Hey kinda off topic, but since RS Motors is the closest place (for me) to get my evo re-tuned...when it comes out of storage that is. How is RS motors? i know a bunch of local Subie guys have used them, but there arn't many Evo's up here at the moment, so i have no idea how they are with 4G's.

 

db is closer. shane is the best

 

I prefer to turn the boost up. It makes rallying much more fun. :P

 

Reminds me of my SRT-4.

With the srt, dodge engineers new that colder weather = more dense. So in order to keep things as consistant as possible they setup the car to run more boost in summer and less during colder temps. But even with their engineering in summer you would boost 15-16 and hold 13-14. During colder winter temps you boost only 13 and hold ~12 @ redline.

The evo as much as I know is not tuned that way. If I'm not mistaken timing changes during different temps. Also from hot to cold temperatures its only a couple psi difference needed to keep things consistant. Nothing as drastic as going as low as 15 psi from 25. If you must I say lower it by 2-4 psi max. But as long as your tune is not made to the absolute edge with no room for error, I say leave it a lone.

Best thing to have is a wideband. Monitoring a/f ratios can help ensure your in the safe zone.

 

If you were going to store your car over the winter with only a few drives in a few months, I would switch completely over to premium for a few reasons:

1. Cold Starts: E85 is brought to E70 for cold start conditions. Avoid any problems with old/mixed ethanol and put in premium. Also, with the lower octane rating of E70, I would be surprised to see significant power loss differences.


2. Sitting Fuel: Ethyl-Alcohol is hydroscopic (like brake fluid) meaning it absorbs water and is also a solvent. It will create a layer of h2o/fuel that is non-combustible, which can only magnify cold start problems. As a solvent, it has the great ability to suspend extremely fine metallic particles in fuel that can decrease your fuel filter life.

Hope this helps,
-Westy

 

Ron has been great! He has tuned/wrenched on my auto since day 1. I also work with a gent that has a 04 RS and he has had Ron do all of the work for him as well. Nice guy, reasonable rates and very professional.

 

Thanks for all of the help thus far fellas. I think once the real snow/cold weather starts I will flip the switch and run the 93. As for the boost I am going to turn her down 3psi and see how it goes. I find it amazing that E85 (E70) makes the car SOOOO much faster. Almost tough to control at times because the rear end wants to come out on me. That simply does not happen with reg gas. This car is by far the most enjoyable auto I have owned in my life! And I have had quite a few fast cars in my 38 years.

 

Too add, I turn down my boost 1-2 psi as it'll spike a bit higher when its real cold out. I am all 93 though as no E85 in New England

 

Its winter and slick, also the fuel is changing, I would go down a few pounds, and of course watch for knock, it all depends on how crazy your tune is. Might be bad all the way across if you get a bad batch of fuel