Always assumed that was true, I mean by most of those calculators I have used, 8 PSI on a 9:1 motor comes out to something like 14.9 compression ratio. I know this motor can run on pump gas, although my worries come from my confidence in tuning and having a controlled environment to really check the tune, but if it were actually a 14.9 c/r with boost I don't think there would be any chance of it running on 93. You must be right about the cam too, I am assuming because the procharger builds boost with RPM unlike some positive displacement blowers, and works independent of the motor unlike a turbo, the cam seems fairly close to what I'd expect them to spec for an N/A motor. Not the first procharged motor of mine that happened with. On my chevy, I had comp spec me a cam for my procharged 396 stroker LT1 and the blower cam they spec'd was literally 1 degree off from the cam Brian Tooley Racing spec'd me out for when it was N/A.

I talked to a few local tuners around here and they all think I should just let it ride with the 4.75" pulley at 8PSI and 93. Everyone I've spoken to seems to think it would be plenty safe if I just start rich and creep up on timing/fuel slowly. I'm still a little worried though, I guess I just don't trust the accuracy of the FITECH (although most have had great success with it using boost) and I'm worried about starting too rich and hurting the rings.

Going with Meth injection is still on my mind.


I'd love to mix high octane fuel while learning the tune but from what I have heard, it'll pretty much be starting from scratch again dialing the tune in when I decide to switch to all pump gas...and I really don't want to be having to fill up with $10 a gallon race fuel all the time.

FWIW I did a compression test (cold, I know not ideal) the other day just to make sure everything was still OK with the motor since through most of its break in when I was trying to run E85 the FITECH was WAY overfueling.

All cylinders were within 4 or so PSI +/- of 175 and dozens of WOT runs N/A figuring out how the FITECH worked on pump gas with no sign of oil in the catch can, no oil film anywhere around vent hoses, no sign of blow by.

Not sure if the cranking compression tells you anything about its ability to run on pump gas; if it does, I am unaware of what that would be, but figured I'd share.

Have a nice day

Have a nice day

polyspheric, that is is some interesting stuff. It's crazy how unpredictable the power output would be just from adding boost. I guess when you think about it, it makes sense. Differences that may make a slight change in airflow on a motor at atmospheric pressure would be amplified when flowing 2,3,4 times+ the airflow through the same head.

What's the 2JZ in? Sounds like a beast!



So I broke down and ordered a stage 1 snow performance meth injection kit and 3 gallons of their "boost juice"I figured the motor wasn't worth $270 and if I want to hit the 550hp make I'll probably need at least the 8lbs.

I ordered Ngk br8es plugs

What do you guys think I should start with timing and fuel wise with the meth? Never tried this before, and I have some research to do on it this week but figured maybe someone here can suggest a starting point.

I know I may not have needed it, but it would make me feel more comfortable not having to monitor IAT's and give me a little more of a safety margin.

Have a nice day

1mean340, any pics of your car? Would love to see it.

Doesn't the effective CR chart apply!!
http://theblowershop.com/wp-content/uploads/2015/08/Effective_Compression.pdf
I pushed my luck on pump gas and ran out of octane...........

Call NGK they were super helpful and I was running too cold (9) of a plug and explained why to me. Also you want to run a resistor type plug with fuel injection. He also told me a projected tip plug weather copper or irdium would work way better boosted and fuel injected then the ngk non-resitor plug I had in it.

Im 8:1 iron heads, intercooled and run 93 pump up to 15psi
I run my timing thru a msd 6al2 programable and build my own curves. I dont start pulling timing until 5psi and pull 1 degree until 10psi and then 1.75 until 15psi

I called NGK originally when I was on E85 and the plug recommendation they gave me seemed way off from what I was hearing other experienced guys tell me. Not sure why that was, but I changed plugs based on the recommendation of someone on the FITECH boards who had a lot of experience with E85/boosted SBM's and it worked much better. I need a resister plug for the EFI, also I have always heard a recessed tip is what you want for boost so you don't get spark blowout? Not sure if the BR8ES's are too cold, but hopefully it's a good starting point.

IMG_2604 by Kris A

IMG_1393 by Kris A, on Flickr
for the gentleman who requested the setup pic, this is prior to cutting out a new main bracket out of .75" aluminum.

So much mixed info about meth injection out there. I have heard some say don't rely on it as a fuel source, it only helps reduce IATs. Heard others say that the reduction in IAT's is a myth perpetuated by saturated IAT bulb style IAT sensors giving false readings. Most people seem to be saying to tune it without meth then add the meth. Only issue is, I bought the meth kit so I didn't melt my motor down while tuning.

Have heard some say it will barely affect AFR's, other say it can drop them significantly and leave the fuel injection system to max out trims trying to adjust.

I had always thought rich would be safe, but others saying i'm looking for ring trouble if I start with a rich AFR.

Just want a safe starting point, mainly because I still have some belt issues with the blower and I would love to be able to sort them out before paying for dyno pulls with a professional tuner. I just need to be able to do a hand full of runs to make sure everything is working correctly so I'm not paying for dyno time to shred belts.

Right now I am thinking i'll set a target AFR of 11.7 and spray the meth (boost juice, basically a 50/50 meth water blend) as soon as boost kicks in. start timing at 22 degrees to be safe






More photos of the build here
https://www.flickr.com/photos/145918422@N04/with/33639843983/

I built the blower bracket around an SD concept crank pulley, built an alternator bracket to mount a GM 140 amp on the driver's side. Had problems with the blower throwing belts. Built a brace to the rear of the blower bracket and recut it out of 3/4 T6061. Seemed to help, but belts would still jump ribs and split in half every few runs. Alignment looks dead on. Thinking at this point it's either that Dayno tensioner isn't up to task and is bouncing too much or I am getting deflection on the idler pulley which is basically just a really long bolt and spacer (I have a fix I am going to weld up today) or the belt throwing may have been from the fitech bogging and hesitating bad with E85 as the sudden change in rpm tends to throw belts. But all that is whole other topic lol.

When they suggest something besides 50/50 water/methanol, it's frequently 1% acetone to help them stay mixed.