CobraMarty

FPR is in the gas tank, returnless system on these Jeeps.
MSD BTM will not work with computer controlled ignition timing, need to control the cam position sensor signal and the crank position sensor signal. have to do both and not just one or will get a CEL.


Those are both old methods to try and control fuel requirements and timing retard under boost. Both will not work with the Jeep 4.0. Older carb versions, regular distributor ignition and renix systems maybe.

s346k

wow. just wow.

rumors of hpt releasing jtec support have been floating since May. that'd be the best tuning solution IMHO if it were available. this thread outlines, in fine detail, why I have opted not to mod the jeep beyond a hot air intake. not to mention I dont have thousands of dollars lying around to burn.

rch10007

Did megasquirt ever get mentioned on this forum?

CobraMarty

This thread outlines just how you can't just 'throw a turbo or supercharger on it'. It's not that easy if you don't know how or what you are exactly doing. Most every thread where someone thinks that they 'can do it', all fail. There are ways to do it easily but everyone 'has better ideas' on how to do it. Unless you have actually done it, it is hard to give advice on what works. I agree that there are many ways to do the same thing, but support on these 'other ways' is lacking.


If you drive a supercharged XJ you will be amazed and sold.
Free rides always available in Philadelphia area.

CoffeeCommando

... so they mounted the wideband 02 2 feet downstream of the catalytic converter. Thoughts?

rch10007

Does it get hot enough that far out to even produce a reliable signal?

concealer404

If you can add forced induction to a vehicle, you can convert to return-style fueling. Not terribly hard.

MSD BTM absolutely works with computer controlled ignition timing. Been done on thousands of vehicles.

Does it work well? No. It's an old method. Just like a 7th injector and messing around with a stock ECU and map clamps.

Sounds fun.

A few times. I mentioned it, and the XJ-R runs it with great success. Pretty simple. I have two vehicles that run it.

Thoughts? Stupid. Should be near the collector.

Widebands don't measure heat. They have built in heater circuits.

CoffeeCommando

I'm having them relocate it to before the collector and installing a second one for the other collector since it's a 2000 with 2 catalytic converters after the collectors on the down-pipe.

30 months in Afghanistan as a contractor has given me a serious financial boost. The reasons I didn't start this myself in my garage is because I suck ***** at soldering, I have no skills in welding, with the sounds emanating from inside the engine I didn't know what to expect, and even with a cherry picker there is no space for me in my garage to use it.

I also didn't want to spend months of all of my spare time picking away at it. In hindsight I'm glad I handed it over to them still because of all of the other things they found that I might have missed in the process even if I had the capabilities to do it myself.

concealer404

My bad, forgot it was a 2000.

They make dual-channel wideband kits that would probably be good for what you're doing, but also gross overkill.

I'd put it as far forward as you can once the exhaust turns into a single pipe. On this low boost with your tuning solution, don't suppose it matters a whole lot of it's after a cat.

CobraMarty

$400 for a MSD BTM + harness and limited/primitive linear control over timing retard vs. the Split Second Control box where you have full program-ability with rpm/boost table.
$200 for a FMU + fuel lines and + rerouting for a return fuel line + need larger fuel pump to be able to supply the higher fuel psi and fuel volume.
I've had poor reliability with MSD over the past 30 years. Don't want failure in this part.

I'll stick with Split Second FTC-1 Control box. Less $, reliable, proven over 90+ Jeep 4.0 installs. It is really a 'standalone' computer for control of the 7th injector. It is plug-n-play, has it's own MAP sensor and gets signals and power from the stock harness. It is a 'piggyback' for the timing retard as it intercepts the cam and crank position sensors and retards those signals also fully programmable with rpm/boost table.

s346k

seems like a awful lot of work to still get drug by a camry on the interstate.

concealer404

You can get a BTM and FMU all day lightly used for $200 for the combo. Because they suck, and nobody uses them anymore.

I know the SS is proven and such, but i just can't wrap my brain around spending many thousands of dollars on a stroker motor, adding forced induction, and leaving the stock ecu anywhere near the thing.

That's my only point. If it works, it works, but end result, you're leaving power, efficiency, and safety on the table going with anything other than a standalone ECU. And that's not something that can be argued. Additional injector setups were commonly used in the 80s and 90s because that's what was good back then. (Greddy Rebic, HKS AIC, PFC FCON, GCC, EGC, etc) They aren't used anymore because this sort of thing is two decades outdated.

I know you have some stake in the Split Second being awesome and all that, and i'm not trying to beat you up over it. I hope it works out great for OP, because i'm really interested to see what this thing does once it's sorted.

CoffeeCommando

I still need to order that injector. It totally slipped off of my radar somehow. Any idea what kind it is Marty? I know Sprintex is in Australia and they're about 14 hours ahead so it's 2:30 AM saturday there now.

CoffeeCommando

It doesn't matter what you drive there's always something faster. I'd prefer it to last at least another 100K miles versus being a little faster and wiping out another cam lobe after a few thousand miles. Been there done that twice. That sucks far more than watching a little 2000 lb car with a 6 speed transmission out run me. ... if it can.

It's going to blast a Camry out of the water on the interstate, then pull off on a dirt road and climb a mountain afterwards while there's a rainbow in the sky and angels are singing.

CobraMarty

Absolutely, but back when EFI started before there were electronic wizards, everyone still thought mechanical like carbs and rising rate FMUs were born. I used them at the time. Even before them was the MSD BTM useful on roots SC engines that wanted more than just lock the ignition and advance at 20*.

Unfortunately today with OBD/emission/smog checks and inspections cat converters, etc, on a DD which is legal, you are pretty stuck with the stock ECU.
Only a few aftermarket/standalone ECUs even support OBD2. And there are currently no aftermarket/standalone ECUs that are plug and play, already programmed, OBD2, direct replacement for the Jeep 4.0. Offroad racers and JeepSpeed types have all the options available.

And our Jeeps are from the 80s and 90s and require 80s and 90s thinking/technology to get them to work.
Unfortunately we can't use today's tuning strategies on them. Sure it would be nice if EFIlive, etc supported the Jeeps. Everything is a compromise. The Jeep ECU can be tuned using SCT products but so far only one guy does it by mail and $$. And you have a very small resolution window to spread now over the boost area. Resolution example like every 1000 rpm and not 100 rpm.

I don't have any stake in Split Second. He was the only one willing to try something different. I looked at the AEM FIC and have 2 units sitting on the shelf. I didn't like how they only modify an ecu generated injector pulse width either + or - and don't actually program the pulse width you really want.

Yep the Jeeps aren't the fastest, run hot, last 200k+ miles, need low rpm grunt and will never win a HP or efficiency/mpg war. They are what they are. Some just like to make them a bit better at what they are.