gze question for the pros

[Lauren]

Reasons for the ABV are to give a smoother transition when the SC clutch engages.

It also allows air to bypass the SC when the SC is not engaged.

It can act as a type of 'blow off' valve though that is rarely the case unless you stick on a big pulley and do nothing with the ABV. On a standard pulley the ABV's in our experience have a propensity for leaking boost pressure which is not what you want.

[NoHachi]

Its there to combat compressor surge on most decently designed supercharger systems. You snap the throttle shut and you have sudden vacuum in front of the charger and high pressure beyond. Some air slips back through the charger, gets pumped back out, slips back etc. Constantly adding heat to the charge in each cycle and slowing down the supercharger blades.
Adding a bypass valve that triggers on vacuum gets rid of that.

Better throttle response, less heat and a longer living Eaton. Lots of write ups on the net. Not bad for 20$ valve imho.

[Lauren]

It's not an Eaton SC, it's a roots type blower.

I see what you are saying, but the reality of driving it (as did for 30K miles like this including numerous trackdays) is that it works just fine. Sure there is less of a transition to on boost, but that's no issue really.

The supercharger does turn into a hairdryer to an extent at higher rpms, so intercooling is key here. What you refer to would only heat up the charge when you are not on the throttle and would be instantly cleared the moment you are back on it again. The SC blades would not slow down because the clutch remains engaged 5 seconds after you lift off.

[ae86driftmaster]

interesting info: also what is (IYSWIM)?

ok my 101gze its in a ae86 with a top mount
i was pushing 10 psi and i would crack 11psi in the winter time with my stock set up... and my last 1/4 time was 14 sec flat with a wasted clutch!
but a few months later one of my crank bearing gave out....so i redid everything and going with a fmic i was using the greddy digital boost guage

now when i had the car running i did notice .. i would top out @ 130ish m.p.h./209 km i would feel power becomes erratic....and fuel cuts of...

these are my very 1st dyno runs w/stock exhaust manifold and crappy cat back....when i first had the car.... before i started doing the mods... i keep improving but never had to chance to dyno before motor went but definitely a big difference




i did a few things..to reduce heat soak on the top intercooler..
1) had the intercooler inlet and outlet elbow replaced with bigger ones...

2) I added washers to the back of the hood to lift it.....to allow the engine bay to breath easier
3) installed a 12 electric fan for the radiator and placed it in front of the super charger where it would get the most air....
4) i bought a temp gun and started measure heat sources....my header would reach over 750 degrees...after 130mph run..so i wrap them with thermo tech....last time i measured 400's after 130 mph run...
5) cut a piece of cardboard the size of the intercooler and wrap it with a couple of layers of heavy duty aluminum foil and place it on the top of the motor to reduce the radiant heat of the motor...
6) purchased a 7in electric fan that pushed around 600 cfm threw that on top...
7) on the intercooler mounting brackets i cut up pieces of silicon hose and used them as washers to also reduce heat soak from the brackets..
i did measure the temps after and there was nice drop on intake temps....but the was a while ago and lost that paper....i think was at a 95-100 (dont quote me) before temp where around 120-135 normal operating temps
i ended purchasing the carbon Dmax vented hood..that work well...& they are proven to reduce engine bay temps

here is their test link
http://www.jdm-option.com/eng/parts/06_06/dmax.html



now im thinking on the front mount....to do 2inch pipe from the s/c to the intercooler and 1.5 or 1.75 pipe to the intake...to help keep s/c velocity up since im adding lenght....



test fitment



but im chaniging the intercooler with a smaller lenght cuz i realize when i purchased the Levin conversion the light brackets are the way of the pipes

[NoHachi]

Eaton == Roots.
Guess the clutch could do much the same thing, nevertheless, just suggesting that its worth reading about surge and by pass valves and see if they have their merit on the gze.

[Lauren]

Okay, good stuff with the new intercooler. Unfortunately the top mount intercooler is in a pretty compromised position and heat soak is a real problem when you start adding big pulleys and the like.

Can I ask are you running the stock fuel pump? If you are you need an adjustable rising rate fuel pressure regulator. This is because on the 101 SC the fuel pump has a higher flow rate but lower return pressure. You can use the stock fuel pump fine, but you'll need an adjustable rising rate fuel pressure regulator which needs to be setup on a rolling road. I had this done to mine not long after the conversion. Gained 15bhp (well I was losing 15bhp before).

IYSWIM = If you see what I mean.

What you are talking about when the car tops out at 130mph sounds like heat soak, so the boost pressure rises until it hits one bar at which point the spark is cut, but not the fuel which usually results in flames out of the exhaust.

A better way to measure efficiency is to measure the inlet and outlet temps of the intercooler. Power drops off when the outlet temp of the intercooler hits about 70C.

Years ago we did a load of tests on this:

http://www.mr2.net/article_charge_temp_monitor.html

Nohachi:
Sorry, I always associated Eaton with the twin screw type SC.

I understand what you are saying. I am basing what I am saying on a number of years of experience running modified SC's. I had an AE92 spec engine:

http://www.mr2.net/trackdayqueen/beardpt2.htm

I ran this engine on numerous trackdays (I used to work for a trackday company) for a few years, doing well over 30 trackdays with no issues running without an ABV. I'm not arguing that you could spend ages looking at surge and the like, but I just found a solution that worked well without issue.

[ae86driftmaster]

i like the work you did on the mr2...looks good & inventive


yes prior was running the stock gts fuel pump i think its around 90liters?... w/ the greddy e manage (blue) now i have the Tomie type s fpr to install...
i also went ahead and had the injectors sent to RC Engineering and had them cleaned & calibrated ...


i thought it was the fuel cutting off or the governor kicking in once it around 130 mph.....what is the top speed should be on a 101?

also i did have some issues with the coil packs.....once in a while they would act up and i would have a erratic spurts while driving like the car want to shut off?...dont know if it was the heat causing ...but i noticed they would turn green in the coil pack...and would have to clean them off...i got the hks twin power now so hopefully this would help

what do you think about going a 2inch from the s/c to the intercooler & smaller diameter intake pipe 1.5 or 1.75 to the intake .....since im adding lenght