Miata Turbo Forum - Boost cars, acquire cats.

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-   Supercharger Discussion (https://www.miataturbo.net/supercharger-discussion-38/)
-   -   Here's a thought... (https://www.miataturbo.net/supercharger-discussion-38/heres-thought-20462/)

Eryan36 05-04-2008 11:36 AM

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. ;)

akaryrye 05-04-2008 01:47 PM

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

oreo 05-12-2008 09:05 PM

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?

Jefe 05-12-2008 10:21 PM

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?

steelrat 05-13-2008 02:22 PM

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.


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