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Supercharging questions

Posted: June 18th, 2018, 9:00 pm
by Cosgray
Okay. I've had my 4.7 stroker since December. I love it. however, I built it with the intention of supercharging it (low boost 5-8psi). it runs fine as is, no problems. its in my '99 XJ. I have sourced my supercharger, a roots style, an SC14 (max boost is roughly 9ish psi based on the model i picked up, as well as calculated RPM of the charger). I'll be fabricating all of my own intake tubing.

I want to run a Rising Rate Fuel Pressure Regulator to increase pressure under boost, however due to my Jeep being a '99, I do not have a 2 port fuel rail. Could i run said RRFPR off of the shrader valve and route back to the gas tank? or will the in tank pump slow it's rate due to the pressure, thus not doing anything?

any input would be appreciated.

bonus pics of my jeep and motor
21041773_1917780485210678_4776930783447220224_n.jpg
25006809_168656283868285_7212636045865648128_n.jpg

Re: Supercharging questions

Posted: June 19th, 2018, 7:26 pm
by Cummins90
The 99 has a regulator in the tank so a rrpfr on the rail won't change it. The neon guys do the "spoolboy mod" for a return system. I'm not sure if it would work with a jeep fuel basket. You could also use a piggyback and larger injectors and keep the returnless system. That is a cool little charger btw. Are you going to keep the clutch for a valet mode?

Re: Supercharging questions

Posted: June 19th, 2018, 10:37 pm
by Cosgray
I assumed as much for using a RRPFR with a stock fuel pump. (been planning out custom fuel cell anyway, so maybe now I'll have a reason to do it, with custom fuel delivery). I had never heard of the spoolboy mod before, but after doing some research, I'm quite intrigued. might take more of a look into it, definitely cheaper than a custom fuel cell. I'm for sure going to start with the clutch for sure being used. it'd be nice to have the option to leave it installed if it's not quite working right, and just off. It's nice that the SC14 has its built in bypass valve, leaving less work for me.

besides, if i throw the SC14 on a switch, it'll be a nice little "Oh SH*T" moment to whoever is riding with me, or whenever I wanna further show up one of the Ricers here in Tucson (dumb ricer's here... I'm into the race scene here, and most can't keep up).

side note: I'm going to do something possibly very strange with my intercooler. Already I have a Cowl intake on my Jeep. I'm going to find a way to put the intercooler in the driver side of the cowl, get rid of any possible clutter in the engine bay)

Re: Supercharging questions

Posted: June 21st, 2018, 10:51 pm
by Cosgray
Okay. I thought of something, and I'd like some input here. What if I installed a 7th injector, with injector control module? then I can tune for A/F mixutre, and it becomes a bolt on and off install. any ideas?

Re: Supercharging questions

Posted: June 22nd, 2018, 4:44 am
by SkylinesSuck
You need timing control for forced induction.

Re: Supercharging questions

Posted: June 22nd, 2018, 4:45 am
by SkylinesSuck
Has anybody mentioned getting your PCM tuned by Ryan?

Re: Supercharging questions

Posted: June 22nd, 2018, 6:51 am
by Cummins90
Yea timing control is important. Oddly enough ive been putting more and more back in. I started with 1* retard per psi but have cut it down to 0.25* per psi with 60/40 meth, before the m90, on at 8psi. AFR transitions to 11.5 by 5psig.

Once open loop fueling has started a 7th injector may work. I have no experience with it. You will need a map clamp. I hear of people using a 2 bar map sensor which doesn't make a lot of sense to me. If it's still a 0-5 volt range 0v being 0kpa and 5v being 200kpa then wouldn't the ecu only read WOT at appx 180-190kpa? With an ECU recscale yea sure but I get the impression that people just throw a 2bar sensor in with the stock ECU?

In other terms you will need to go with more control. You can get your ecu tuned maybe Ryan will pop in and give some prices and advice. You can tune on your own from the ground up with megasquirt or you can tune on your own with a piggyback like an AEM FIC 1913. What state are you in? ( emissions requirements)

Re: Supercharging questions

Posted: June 22nd, 2018, 7:37 am
by Cosgray
I'm in Arizona, registered in Show Low, with no emission requirements, so no biggie there. I've been considering Megasquirt. I've got a guy that does Megasquirt instalsl, and another guy for tuning over at Envy Motorsports (they did a 5.0 supercharged stroker in a TJ for Sema last year). been meaning to hop on over there, just havent had the time.

Re: Supercharging questions

Posted: June 22nd, 2018, 7:38 am
by Cosgray
And to do timing control, i would need to switch to coil on plug right? swap to a 2000-2001 cam sensor and coil rail (or custom coil setup)

Re: Supercharging questions

Posted: June 22nd, 2018, 9:07 am
by Cummins90
FIC will retard timing by intercepting and delaying the CPS signal to the ECU. Works just fine on the 1996 XJ with distributor.

Re: Supercharging questions

Posted: June 22nd, 2018, 12:50 pm
by SkylinesSuck
The PCM controls it so, so you get that tuned, and your done. Timing, fuel, everything.

Re: Supercharging questions

Posted: June 23rd, 2018, 11:47 am
by Cosgray
Okay so from what I've gathered from everything;

Install the supercharger,

Add fuel pressure regulator (and modify fuel pump assy)

Tune the stock PCM to handle timing.

Or

Custom ecu

Right?

Re: Supercharging questions

Posted: June 23rd, 2018, 7:24 pm
by Cummins90
Stock pcm reprogrammed to handle boost and scaled to handle bigger injectors.

Or

Standalone ecu with bigger injectors i.e. megasquirt

Or

Piggyback like and FTC or AEM FIC with bigger injectors.

Re: Supercharging questions

Posted: August 11th, 2018, 8:19 am
by 6sense
I would highly suggest split second because they have some great plug and play systems Aem is great but you will need to spend some time tuning I’m not sure if they have a base programs for Jeep 4.0 engines.To me really depends on how much power do you plan on making.I would use split second up to about 450Hp. After 450 I would use Aem/halttec.I run split second in my 300+hp in my 99 Jeep Grand Cherokee.