Jlt Rai - 2003-04 Mach 1 Registry Owners Club

Castillo830 · 08-13-2008, 07:27 PM

I just installled the JLT about 2 weeks ago. My gas mileage has decreased to about 160 a tank. That's what I got on the last on anyway. This was all in-town driving. I know this isn't normal because I'm not on it all the time. Anybody know why?

3150Mach1 · 08-13-2008, 07:35 PM

The JLT RAI will actually make the car run rich without a tune. Get it tuned and leaned a bit.

Mustang9668 · 08-13-2008, 07:35 PM

What else is done to the car? Might be time for a dyno tune.

Edit: Guess I was too slow......as usual

Castillo830 · 08-13-2008, 11:35 PM

Nothing other than the RAI is done to the car. And what kind of tune do you say I would need?

2k4mach · 08-13-2008, 11:39 PM

ive yet to see a CAI wack out the a/f to the point where when its in closed loop mode that the 02 sensors cant compensate and correct for the correct a/f of 14.7.

they will cause a rich or lean condition when in OPEN loop mode depending on what cai you have.

G · 08-14-2008, 12:42 AM

Quote:

Originally Posted by 2k4mach

ive yet to see a CAI wack out the a/f to the point where when its in closed loop mode that the 02 sensors cant compensate and correct for the correct a/f of 14.7.

they will cause a rich or lean condition when in OPEN loop mode depending on what cai you have.

I agree.

I'm not buying the jlt is the reason. I have one on both cars and it didn't adversely change my mileage. I've been checking my mileage closely and my mostly stock AB has about 1/8 tank remaining (according to the gauge) and it has 238 miles on the tripometer.

What kind of fuel, E10 will kill your mileage too?

You may have other issues like sensors or air leak. If it's that bad before long it will drive the fuel trims enough to throw a code. Good luck, but if that sucker is installed right it's probably not the issue.

Castillo830 · 08-15-2008, 12:13 PM

I use premium fuel. I think it's like 91 Octane. But I used it just in town and it averaged like 13.5 mpg. That's with getting on it from time to time. I'm sure that's not normal right?

Mustang9668 · 08-15-2008, 07:46 PM

How many miles are on it? Could it be time for a tune up? I don't think that would cause such a big difference but maybe take a look at the plugs if they haven't been changed in a while.

Castillo830 · 08-15-2008, 08:46 PM

There are like 68K on it.

08-13-2008, 07:27 PM	#1
Castillo830 Registered User Join Date: Apr 2008 Location: Texas Posts: 66	Jlt Rai I just installled the JLT about 2 weeks ago. My gas mileage has decreased to about 160 a tank. That's what I got on the last on anyway. This was all in-town driving. I know this isn't normal because I'm not on it all the time. Anybody know why?

08-13-2008, 07:35 PM	#2
3150Mach1 Love my Mach Join Date: Apr 2005 Location: Charlottesville, VA Posts: 13,678	Re: Jlt Rai The JLT RAI will actually make the car run rich without a tune. Get it tuned and leaned a bit. __________________ 2003 slowmatic 11.105@117mph w/125 shot of Nitrous best to date Kooks LTsw/OR X, elect cutouts, JLT RAI w/C&L 85 MAH,1" Spacer,PP Lower intake,Accufab TB,160 T-stat,EF Cooling Mod,NX Kit,Mez Electric Water pump,SLP Linelock,FRPP 4.10s-Alum Dif Cover-Alum Driveshaft & SL, Steeda Bumpsteer,MM Alum rack bushings,Deep Alum Tranny pan,Predator,Steeda AUCAs,MM ALCAs, Dspecs,MM CC plates & FLSFCs,MRT Guage cluster,AEM WB,MRT hood struts,Seq TLs, carbon fiber hood/trunk/Cobra wing,220 amp alt

08-13-2008, 07:35 PM	#3
Mustang9668 saving pennies Join Date: Apr 2008 Location: Griffin, Ga Posts: 1,487	Re: Jlt Rai What else is done to the car? Might be time for a dyno tune. Edit: Guess I was too slow......as usual __________________ 03 Mach 1--Auto, 4000 stall, 96 cobra intake cams, 4.10s, ARH L/T's, off road X, Moser 31 spline axles, Eaton Posi diff., MM FLSFC, Tokico D-Specs, k&n filter, 17x9/10.5s AFS Mac wheels 03 Cobra--18x9/10.5 TSW Nurburgring Wheels, Nitto NT05's 275/295, Stiegemeier ported, 2.87” pulley, Canton 9-qt oil pan, Spec Stage II clutch, MM coilovers, Bilstein Shocks/Struts, LFP heat exchanger, LFP radiator, Evans cooling system, 14" Brembo 4 Piston calipers, 470whp, 460ft-lbs

08-13-2008, 11:35 PM	#4
Castillo830 Registered User Join Date: Apr 2008 Location: Texas Posts: 66	Re: Jlt Rai Nothing other than the RAI is done to the car. And what kind of tune do you say I would need?

08-13-2008, 11:39 PM	#5
2k4mach LuLz Join Date: Dec 2003 Location: Cedar Park, TX Posts: 19,294	Re: Jlt Rai ive yet to see a CAI wack out the a/f to the point where when its in closed loop mode that the 02 sensors cant compensate and correct for the correct a/f of 14.7. they will cause a rich or lean condition when in OPEN loop mode depending on what cai you have. __________________ 11 Sterling gray GT500 coupe 08 Silver Z06 1058rwhp/1073rwt @ 15psi 14 Silver Q50S Vortech blown 04 DSG Mach 1 (stolen) 03 OW Mach 1 (sitting in a field rotting away)

08-15-2008, 12:13 PM	#7
Castillo830 Registered User Join Date: Apr 2008 Location: Texas Posts: 66	Re: Jlt Rai I use premium fuel. I think it's like 91 Octane. But I used it just in town and it averaged like 13.5 mpg. That's with getting on it from time to time. I'm sure that's not normal right?

08-15-2008, 07:46 PM	#8
Mustang9668 saving pennies Join Date: Apr 2008 Location: Griffin, Ga Posts: 1,487	Re: Jlt Rai How many miles are on it? Could it be time for a tune up? I don't think that would cause such a big difference but maybe take a look at the plugs if they haven't been changed in a while. __________________ 03 Mach 1--Auto, 4000 stall, 96 cobra intake cams, 4.10s, ARH L/T's, off road X, Moser 31 spline axles, Eaton Posi diff., MM FLSFC, Tokico D-Specs, k&n filter, 17x9/10.5s AFS Mac wheels 03 Cobra--18x9/10.5 TSW Nurburgring Wheels, Nitto NT05's 275/295, Stiegemeier ported, 2.87” pulley, Canton 9-qt oil pan, Spec Stage II clutch, MM coilovers, Bilstein Shocks/Struts, LFP heat exchanger, LFP radiator, Evans cooling system, 14" Brembo 4 Piston calipers, 470whp, 460ft-lbs

08-15-2008, 08:46 PM	#9
Castillo830 Registered User Join Date: Apr 2008 Location: Texas Posts: 66	Re: Jlt Rai There are like 68K on it. __________________ JLT RAI

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