Here's a thought... - Miata Turbo Forum -Boost cars, acquire cats.

Welcome to   Members

Supercharger Discussion For all you misguided souls. 949 Racing - Rim & tires

LinkBack Thread Tools Search this Thread
Old 05-04-2008, 11:36 AM   #1
Thread Starter
Join Date: Apr 2008
Posts: 1
Total Cats: 0
Default Here's a thought...

Ok, I'm pretty sure I'm running a bit rich. No, I don't yet have a wideband sensor, but based on the gas mileage I'm getting and some things I've read about the JR M45 being a little rich, I think I'm close to right. SO. I'm sitting right at 5psi right now. I have the JR BTC, so I can adjust ignition timing to some extent. I also have their RRFPR (which apparently is blamed for richness). Would it make sense to get a slightly smaller nose pulley? It would up the boost a little more. Which could even out the AFR, and take care of the richness. And then retard spark a bit.


Would that setup just make more boost with the same richness problem?

I want megasquirt and an intercooler, basically.
Eryan36 is offline   Reply With Quote
Old 05-04-2008, 01:47 PM   #2
Elite Member
iTrader: (5)
akaryrye's Avatar
Join Date: Jul 2006
Location: Central California
Posts: 2,526
Total Cats: 0

There may be a reason that JR designed the setup to run rich. I think those blowers can heat up the air a good bit (more than a turbo) and without an intercooler, I bet intake temps get pretty high ... especially on a hot day. That extra fuel might be what keeps you from detonating. However, if you do go with the other pulley and you dont have to pull more than a few degrees of timing without detonation then go for it.

Also, you do realize that the RRFPR does nothing until you tip into boost right? This means that you should get normal gas mileage if you drive mostly out of boost ... on the flip side, with any forced induction you are putting more oxygen into the motor and it simply uses more fuel, but only when in boost. One more thing to consider is drag on the motor caused by the supercharger ... but i dunno how much of an effect that has.

good luck mate, hope that helps
akaryrye is offline   Reply With Quote
Old 05-12-2008, 09:05 PM   #3
Junior Member
Join Date: May 2007
Location: Toronto Area, Ontario
Posts: 77
Total Cats: 4

Also, you do realize that the RRFPR does nothing until you tip into boost right?

unless you have a very heavy foot, your gas mileage is probably more related to condition of plugs etc.

what kind of mileage are you getting?
oreo is offline   Reply With Quote
Old 05-12-2008, 10:21 PM   #4
Senior Member
iTrader: (7)
Join Date: Mar 2005
Location: VT
Posts: 939
Total Cats: 0

Do yourself a favor and invest in a WBO2.

I have both the LC-1 and the Zeitonix ZT2, both are excellent units.

I'm running a smaller pulley, and heat is a concern (my intake takes it from lower rightside of the car), (near ambient, more of a direct shot into the intake, which on my car is against the passenger firewall).

What plugs and gap are you running?
Jefe is offline   Reply With Quote
Old 05-13-2008, 02:22 PM   #5
Senior Member
steelrat's Avatar
Join Date: Jul 2005
Posts: 514
Total Cats: 0

Have you got a fuel pressure gauge? The JR AFPR normally is adjusted to increase the pressure in the rail to around 50 or 54 psi (without the vac hose connected). So you might be spraying a little more than stock @ idle/off boost, but not much.

Have you retarded the timing too much with the BTC?

Also as a thought, check your by-pass valve. Make sure it's still working, otherwise, the blower could be producing boost more of the "idle time".... and it will heat the charge a lot more, so you'll need to retard the timing more.

steelrat is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
TX Crew - Where to eat in Austin? Efini~FC3S Insert BS here 15 03-03-2013 03:00 PM
100K what would you spend it on/invest in if you HAD to jtothawhat Insert BS here 91 01-27-2010 07:16 PM
Gauging interest-Rad hose relocate SKMetalworks Engine Performance 5 12-17-2009 12:52 PM
$125 retard mistake Turbo_4 General Miata Chat 0 04-22-2009 04:06 PM
If I were going to buy an MR2... m2cupcar Insert BS here 11 04-10-2008 11:43 PM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 06:25 AM.