Tom's B6 Build Thread

[TominMO]

14.5 afr should still make good power. Mid to high 13's are the sweet spot for a modern fuel injected n/a engine unless it's horribly inefficient. You don't want your N/A econobox running in the 12's unless your compression numbers are 11:1 or higher or your fuel quality is on par with the swill they sell south of the border.
With a flat 14.5afr I would be suspicious of your tps. Looks like it's not seeing WOT and it's staying in closed loop, which will do it's best to keep that 14.5 target. Check that your WOT switch is working. Also, you should have had your cover plate popped off the VAF so you could tune that while your on the dyno. Funny that Matt never mentions the most easily tuned component on the system.

At the rate the HP curve was going, it looks like it would have gone to ~100 HP @ 5500 RPM. TQ was apparently flatlined at 91; but who knows, with proper AFR @ WOT? He did mention the VAF, saying it was not a rheostat like many people think, but an on/off switch for closed/open loop. I'll look into the TPS issue.

Also, tuning your AFR on a non load bearing dyno is like bringing your surf board to the public pool. Engine fuel trim is highly dependant on load. If the dyno cannot replicate the cars load, then it can't be effectively used to optimise your tune. Does that dyno jet have the eddy-current option?

No clue about the eddy-current option, or even what it is. I'm getting the idea that I really should do the AFPR and buy a wideband to do some self-tuning, then go back to the dyno. And check into the TPS. BTW I found my AFPR from Matthew, but I have a problem; the custom connector Matt made out of the old stock FPR went to Kevin Shankle when he stole my custom Dickmeyer intake, because I didn't think to remove it. So now I have to come up with a piece that I can bolt on in place of the old FPR. Does this exist in the aftermarket, like for Miatas/BPs, where I can just order one? Basically I'm talking about a little two-bolt flange that replaces the old FPR and a simple tube coming off it to attach a fuel line. EDIT: referred to as a fuel rail adaptor.

[bhearts]

Nope. L jetronic based systems go open loop at WOT.

If he turns pressure up, ecu should adjust for fuel in closed loop

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[TominMO]

eBay Miata fuel rail adaptor. Also says it fits the B6! I found a British supplier that said the same thing, so I have independent confirmation. Gonna order it. I have a spare Aspire intake I will try to fit it onto as well, just to see if that works, and maybe I can try it out on a Festy intake at the JY. I would expect that if it fits the Aspire it will fit the Festy too.

Question: what should I use to seal the threads that is fuel-resistant/proof?

[bhearts]

eBay Miata fuel rail adaptor. Also says it fits the B6! I found a British supplier that said the same thing, so I have independent confirmation. Gonna order it. I have a spare Aspire intake I will try to fit it onto as well, just to see if that works, and maybe I can try it out on a Festy intake at the JY. I would expect that if it fits the Aspire it will fit the Festy too.

Question: what should I use to seal the threads that is fuel-resistant/proof?

White plumbers thread tape, or yellow, or blue. If you used enough of it, 20 wraps, you'll be good.

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[Advancedynamix]

At the rate the HP curve was going, it looks like it would have gone to ~100 HP @ 5500 RPM. TQ was apparently flatlined at 91; but who knows, with proper AFR @ WOT? He did mention the VAF, saying it was not a rheostat like many people think, but an on/off switch for closed/open loop. I'll look into the TPS issue.

Also, tuning your AFR on a non load bearing dyno is like bringing your surf board to the public pool. Engine fuel trim is highly dependant on load. If the dyno cannot replicate the cars load, then it can't be effectively used to optimise your tune. Does that dyno jet have the eddy-current option?

No clue about the eddy-current option, or even what it is. I'm getting the idea that I really should do the AFPR and buy a wideband to do some self-tuning, then go back to the dyno. And check into the TPS. BTW I found my AFPR from Matthew, but I have a problem; the custom connector Matt made out of the old stock FPR went to Kevin Shankle when he stole my custom Dickmeyer intake, because I didn't think to remove it. So now I have to come up with a piece that I can bolt on in place of the old FPR. Does this exist in the aftermarket, like for Miatas/BPs, where I can just order one? Basically I'm talking about a little two-bolt flange that replaces the old FPR and a simple tube coming off it to attach a fuel line. EDIT: referred to as a fuel rail adaptor.

The TPS on a Festiva is just 2 switches that work as Matt describes. The VAF has variable resistance, but isn't a true rheostat. It has two adjustments. One spring adjustment and a bleed screw. You have to cut the glue and pop the black cover off for the spring preload and pull the tamper proof plug for the bleed screw. The spring preload is a low resolution adjustment and the bleed screw for fine tuning.

An Eddie-current dyno uses an electric generator to load the engine and convert the work load into electricity. Basically turning the dyno into a huge generator. Power is then measured in kilowatt hours and converted to hp with a formula. DynoJet offers this as an upgrade to its centrifugal dynos. Without the eddie-current option the DynoJet units don't put an adjustable load on the engine. Without a load on the engine, it's impossible to accurately tune the fuel injection for real world driving. Your better off load testing the car and tuning it with a wide band and vacuum guage on the road, and save your money to get the car tested on a load bearing dyno.

[TominMO]

Ordered the Innovate MTX-L wideband, due in Tuesday. Looking at two fuel rail adaptors, will order one Sunday. I don't have Paypal and the one I want is on eBay, so I'm having a friend do it tmw. Once this stuff is installed, I can start some fuel tuning.

[Advancedynamix]

Fun stuff. I think you'll enjoy having a wideband. It's like cheating when trying to get the best MPG on a trip. Lol.

[TominMO]

Fun stuff. I think you'll enjoy having a wideband. It's like cheating when trying to get the best MPG on a trip. Lol.

Yeah I know the feeling. :-)

Went to the JY today and pulled three FPRs: Aspire, 90s Toyota and BP Protege. All three mount to the fuel rail the exact same way, so it's a good bet that the Festy one will be the same as the Aspire's. There were only differences in fuel and vacuum line locations, for different applications. Obviously Toyota and Mazda used the same part supplier for their FPRs. Nissan too BTW.

[TominMO]

Shameless teaser post: considering my next purchase.

B4 I do this tho, I will pull the intake and do some widening and matching wherever possible, to try to get as much flow out of it as I can. Tune the FP with the wideband, then go do the dyno thing. That will give a decent baseline before I add the part in the link, which is after all a pretty major expense. That probably won't happen until spring. I'll have to suffer along with whatever power I can squeeze out of it until then.

Basically, with ~100 WHP @ 5500 RPM, and 80 ft-lbs torque, I would describe it as a B8+ (so far). The B8 is 103 HP crank, so maybe 90 WHP. Not sure what stock B8 torque is, but probably not 80 @ 2250 RPM. Fixing the fuel issue and adding a little intake volume should get it to a BP, perhaps slightly better. But probably no more, without a different cam (I am happy with this one) and a standalone ECU. Greg/Charlie/anyone else with the expertise, what results might I expect with Megasquirt PnP over current stock fuel/ignition management, but keeping it NA? Is it worth $800 to delete the MAF and give me some tunability?

[Flyin4stroke]

Tom's B6 Build Thread

With the wideband you can only go about 5,000 miles on the o2 sensor. After that you start to get different readings. I just replaced my o2 sensor and its a lot better tuning. Now, megasquirt has ve analyze live. You just drive it tunes for you by the afr map you create. Best way to get max mpgs and power. I might have an extra megasquirt sitting around when u start thinking about it. Or it may end up on my mustang....

[TominMO]

With the wideband you can only go about 5,000 miles on the o2 sensor. After that you start to get different readings. I just replaced my o2 sensor and its a lot better tuning. Now, megasquirt has ve analyze live. You just drive it tunes for you by the afr map you create. Best way to get max mpgs and power. I might have an extra megasquirt sitting around when u start thinking about it. Or it may end up on my mustang....

Good info. The MS I would want is specifically the PnP gen2 version for the early-90s Mazdas.

I've been using my Innovate MTX-L in the Aspire as the only O2 sensor, and it has performed fine for several years; except during periods of high humidity with the A/C on, especially rain; then it gets goofy. Turning off the A/C restores it. I might switch to using a 3-wire Denso as the one connected to the ECU and use the wideband only for readouts.

[Advancedynamix]

Shameless teaser post: considering my next purchase.

B4 I do this tho, I will pull the intake and do some widening and matching wherever possible, to try to get as much flow out of it as I can. Tune the FP with the wideband, then go do the dyno thing. That will give a decent baseline before I add the part in the link, which is after all a pretty major expense. That probably won't happen until spring. I'll have to suffer along with whatever power I can squeeze out of it until then.

Basically, with ~100 WHP @ 5500 RPM, and 80 ft-lbs torque, I would describe it as a B8+ (so far). The B8 is 103 HP crank, so maybe 90 WHP. Not sure what stock B8 torque is, but probably not 80 @ 2250 RPM. Fixing the fuel issue and adding a little intake volume should get it to a BP, perhaps slightly better. But probably no more, without a different cam (I am happy with this one) and a standalone ECU. Greg/Charlie/anyone else with the expertise, what results might I expect with Megasquirt PnP over current stock fuel/ignition management, but keeping it NA? Is it worth $800 to delete the MAF and give me some tunability?

It's worth it for someone like yourself, who enjoys changing things and tuning and getting good results. The Megasquirt community is great, and now it's easy to learn about fuel injection and it's tuning.
Also, Megasquirt is an investment for future projects. If you get bored of the b6, you can swap in anything and make it run. It's nice to have that versatility.

[TominMO]

It's worth it for someone like yourself, who enjoys changing things and tuning and getting good results. The Megasquirt community is great, and now it's easy to learn about fuel injection and it's tuning.
Also, Megasquirt is an investment for future projects. If you get bored of the b6, you can swap in anything and make it run. It's nice to have that versatility.

True dat.

[eurotiva]

The b8me in RJ 's car did 97 whp/103 wtq

[TominMO]

The b8me in RJ 's car did 97 whp/103 wtq

Thanks.