What kind of mileage are you guys getting on a megasquirted stock NA FC?

 

I think tofuball is getting in the 20's when he takes it easy on the highway... He's running very lean to get that though... around 16:1 on cruise. Once he gets around to properly tuning his accel enrichments, and his stop 'n go driving parts of the table, I'm sure he'll get better mileage.

Have you actually gotten around to driving your car now? Is everything working right?

 

I've only driven it around town and I get about 13mpg. That is in my FB. Runs real good, though.

20s as in upper 20s or lower 20s? I'm real curious..

I got a FC last week and school started also. (https://www.rx7club.com/showthread.php?t=498585)
The FC I got is auto and at about 70mph it is at 2800-3k. I estimated that it gets 25mpg highway, but can't be 100% sure of that..

Since I've been busy with the FC and getting ready for school, I haven't even had time to tinker with my FB AT ALL since you posted those updated settings for the triggers. I am definitely going to update my settings Friday no matter what. The big problem is school being 3hrs away from my house so I can't work on the FB during the week.

I'm selling off all my FI stuff, at least for the FB. I need the money for FC mods.. It's kind of sad and I really don't want to do it... It is just now running so well.

 

I'm thinking low to mid 20's

Once I get my harness fixed I'll get the GXL tuned and post numbers with an otherwise stock engine.

I believe tofuball drives like 80mph everywhere he goes on the highway, and I'm sure he could get better mileage if he slowed down a bit... He also doesn't have a stock engine... his rat's nest is gone, he ported the throttlebody, and port-matched the intake runners, and is running a non-stock exhaust system... and he's running an S5 NA not an S4 NA... so there are a lot of things that could be causing him to get worse gas mileage.

 

mid 20s on a ported rotary and doing 80 on the highway sounds pretty good to me..

Are you STILL battling those grounding issues??? heheheh
just messin with you, man.

 

I haven't had a chance to work on the GXL for like almost a week... too busy building PnP units and writing code.... in other words... I've been too busy doing work for the rx7/megasquirt communities I did work on the ae86 on Saturday though... I have to get the GXL done this weekend though because the temporary registration expires at the end of the month.

The engine itself on tofuball's car has stock ports, he ported the throttle body and matched the diameters of the intake runners to the ports I believe (that's what I meant by "port-matched.") He also did a little work around the secondary injector bungs inside the intake manifold.

Before we made everything really lean on cruise, he was getting ****-poor mileage... like 15-17 I think. I think we can still get better mileage than he's getting by tuning the accel enrichments to be cycle based instead of time based, and by leaning out the city-driving parts of his map...

I still think he could help his mileage by not having a lead foot too

 

Oh, my bad.. I misread about the porting.

My AE on the FB doesn't correct very much at 50-100kPa/s, but at 400kPa/s I have a 12-13ms correction. (using MAPdot, btw) Which is REAL high, I think. Huge duty cycle spikes at AE time. VE just might be slightly off.. Of course, my setup is basically like an ITB setup. Superquick MAP increases at sudden WOT. I had to tune the low RPM high kPa areas to get better AE response as well, but it's MEAN now. I like it.

Messin around with ae86 cars? I still have not seen one in person around here, a few in Japan and at carshows.. There are a few sr5s in the junkyards, but no ae86. Kind of rare I think.

 

yep, a friend and I are finishing up a 20v 4age swap... just have to finish the harness and some other small things next time I have a chance to work on it, then we're going to tune the MS on it... I'm using 2 rx7 leading ignitors/coils for wasted spark on it...

I'm using TPSdot right now on the PnP unit (tested on my other friend Julian's car) and it revs pretty quick... I've found that having the ignition timing just right at the high MAP low rev part of the map... just a degree or two away from knock really helps the throttle response off idle... Even with the narrow range TPS, it revs very nicely.

We're using TPSdot on tofuball's car as well, but with time-based, the amount of extra fuel is the same at idle as it is at redline... going to cycles based reduces the amt of extra fuel at higher revs, which is what we want.... The rotary doesn't need much accel enrichment at high revs, but needs quite a bit at low revs. We're also using the wide-range TPS, which hurts us a bit as far as accel enrichment goes... with the stock throttle body and manifold, the rotary doesn't need much (if any) accel enrichment above the point when the secondary throttle plates start opening... so we could probably get better behavior if we took that into account as well.

The ideal solution would be a small map of tps/map change vs rpms... there's code like that going into the MS2 soon, and I might try to duplicate that in msns-extra if there's enough RAM after I'm done rewriting the wheel decoder to use all the teeth on the CAS or crank wheel (depending on what car you're talking about)

 

My personal best was ~28 US mpg during a 300 mile 75-80 mph cruise on a cool day. I usually get ~18-20 mpg around town. That's a street port 12A. I cannot go leaner than 15.2 or so without misfiring.

-Mike

 

I don't think tofuball has done any real highway driving like that... not a 300 mile trip anyway... anyone from the Washington DC area knows that the traffic around here is aweful too... he probably does mostly city driving with short highway blasts when it's late at night and there's no traffic. I'll have to ask him...

Hopefully I'll have my GXL ready to go after monday or tuesday, and start tuning with a wideband to get good mileage.

 

Speaking of tofuball.. I PM'd him about a harness adapter cable but haven't heard back. You guys must be crazy busy.

Do you guys make them out of custom AMP connectors(or do they have a part#?), or scavenge ECUs? I might be able to make one myself from an old ECU. Do you guys give out the cable map?

 

BTW, good luck with the 20v conversion.. InitialD!! hahaha

 

Yeah, because our adapters are only good with our custom wiring internally on the MS, so if I sold you something, I'd have to leave everything that doesn't solder to a standard MS pin unconnected on the db37 side.. then you could connect them where you want them. We are very busy though.

I have not given out a map of what we do either, since it's custom to how I modify the MS.

it'll cost way more money than I have to get AMP or another company to produce connectors... the latest I've got is $107,000 just to tool up to do it... and that's without actually getting connectors.

 

ERR.... no way... haha we are doing the 20v conversion mainly because it's more reliable than our 20 year old original engine, and will give us 40-60 more HP over the stock engine.... plus we just like to tinker.

 

If I got something that connects into the stock harness then puts everything I need into the DB37 connector for fuel only, I can handle the rest.
I have a Painless 15wire connector that I use for the daughterboard connections and coil ignitors. Works real well. I've built two MSes with it so far.
Looks like this:
http://home.mindspring.com/~wilkinsj...For%20sale.JPG

A 20v conversion would be kickass.. I bet the sound is friggin cool, especially with ITBs.
How much did the conversion set you back, btw? Seems like the engine isn't TOO awful expensive.

 

$450.00 for the engine, $60 for the wires for the harness, $200ish for the MS, $200 for the wideband, and maybe another $100 for other random stuff....

I'm using v3 boards for all my megasquirts, so I don't need any extra connectors, just the db37, that board has 9 extra pins that can be made into inputs/outputs.

 

Nice. Good deal. Funny how the wideband costs as much as the ECU.. lol

I need one for a v2.2 board with the "ignition wires dangling".. Can either of you make one or should I just wait to talk with tofuball?

 

Hey guys.

Yeh, we're pretty busy, sorry about the lack of a response :O We can't really offer an 'adaptor plug' due to the fact that it's custom made for the way we wire our megasquirts :P


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Yeh, the 20MPG is in heavy traffic all the time. It's not actually 20, it's 19.1MPG :-p And when I DO get on the highway and it's not totally backed up I floor it :P I'm a pretty firm beliver that we are going to soon be out of affordable gas, so I figure I might as well enjoy it while I can ALSO, remember that I am driving a 'vert, and usually the trunk is full of parts or something :p

. . . .

I used to do all highway trips, a long time ago, cuz I dated a girl who lived 274 miles away, but I havent done that for quite a while. But I'll say that the MegaSquirt held up great, I had no issues. Though, five hour datalogs are rather large files.

 

The wiring for the db37 on fuel only is the same on both boards isn't it? So far as sensors, power and injectors, I mean. I've never worked with a v3 board so I don't really know if they're using the same pinout or not. (except tach input, I think?) I'm sure you guys are using the custom pins for your mods and all, but if you could sell me one with those wires disconnected, that'd be good.

I have a connector for ignition already set to go, I can just wire in whatever wires come off the main harness for ignition into the connector I already have setup if you can leave the wires disconnected for me on the harness adapter. If not, no big. I can probably hack something together myself, I just wanted to save myself the hassle..