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This is a question for anyone. I am in the process of building an 4.6 stroker in my 2000 XJ. I was wondering if I will still be able to pass emssions with the following set up"
-stock 4.2L crank
-stock 4.2L rods
-stock 4.0L pistons
note the compression ratio will be roughly 9.7:1
-CompCams #68-231-4, 206/214
-Port factory cylinder to 1.91''/1.50''
-stock head gasket .051''
-stock fuel pressure regulator
-Ford Racing 24lbs/hr injectors
******* I live in Gwinnett County GA so we have emissions<<<< not cool >>>>
This is a question for anyone. I am in the process of building an 4.6 stroker in my 2000 XJ. I was wondering if I will still be able to pass emssions with the following set up"
-stock 4.2L crank
-stock 4.2L rods
-stock 4.0L pistons
note the compression ratio will be roughly 9.7:1
-CompCams #68-231-4, 206/214
-Port factory cylinder to 1.91''/1.50''
-stock head gasket .051''
-stock fuel pressure regulator
-Ford Racing 24lbs/hr injectors
******* I live in Gwinnett County GA so we have emissions<<<< not cool >>>>
I live in a state where there is no I/M....so what would i know......i thing the 24 pound injectors will be you down fall if it don't pass.
They may be to rich at idle.......then again.....maybe not!:dunno:
Maybe he could get an adjustable fuel pressure setup. Id think that with the higher combustion temps from the higher compression ratio that it might offset the added fuel??? Im not 100% on this though.
Maybe he could get an adjustable fuel pressure setup. Id think that with the higher combustion temps from the higher compression ratio that it might offset the added fuel??? Im not 100% on this though.
What do you mean that they lowered the compression? I think what you mean is by the 4.2 going grom 9.2:1CR to the 4.0 8.8:1 CR When you raise the compression ratio the Nox will go up with performance and fuel efficieny (as well as knock) but the HC and CO will go down which is a good thing. People are looking into adding more alcohol content to fuels to help fix these problems while also creating others. Look at the new e90 m3, its running a 12:1 compression ratio yet it fulfills the new LEV2 emissions. Then again we have a lowtech engine....:bawl:
This is a question for anyone. I am in the process of building an 4.6 stroker in my 2000 XJ. I was wondering if I will still be able to pass emssions with the following set up"
-stock 4.2L crank
-stock 4.2L rods
-stock 4.0L pistons
note the compression ratio will be roughly 9.7:1
-CompCams #68-231-4, 206/214
-Port factory cylinder to 1.91''/1.50''
-stock head gasket .051''
-stock fuel pressure regulator
-Ford Racing 24lbs/hr injectors
******* I live in Gwinnett County GA so we have emissions<<<< not cool >>>>
You should have no problem passing emissions with that combination but I recommend that you make sure of that by installing a programmeable computer such as the Unichip and have it custom mapped on the dyno. The '00+ computers on the DIS 4.0 Jeep models are very fussy when it comes to mods.
yo DrDyno thanks for the input but I have another question. Do I really have to have a dyno tuned Unichip in order to pass emissions? Is there a way I could run an chip like Unichip for emissions purposes then a stock pcm with like a jet stage 2. See what I plan on doing is eventually add other mod to the engine such as bigger TB, Intake manifold, and so on. If you dont mind me asking you anymore questions.
You could just run your stock PCM but the likelihood is that the A/F mixtures will be way off at certain rpm 'cause it's locked into closed loop at WOT up to 2200rpm. What's likely to happen is that your engine will run too lean at low/medium rpm and too rich at high rpm. Only a custom programmed computer can correct that and the Unichip is probably the best on the market for the Jeep 4.0. It'll also allow you to optimize the timing advance curve for more HP/TQ. The 4.0 PCM has a conservative timing map to allow the use of 87 octane fuel without pinging. If you don't mind using 91 octane, you can have a bit more timing advanced dialed into the Unichip and gain some performance.
Do NOT use the JET chip. It's useless and it's only tuned for a mildly modified 4.0 with a low restriction exhaust. I removed mine a couple of months ago when it was causing the rev limiter to cut in at only 4500rpm. The only advantage of the JET chip for me was more torque above 3800rpm. From idle to 3800rpm, I have more torque without the JET chip.
Dr.D your the shit dude I appreciate all the insight I will definately keep you close for other questions. I am a tech at Allsouth Autosports in Buford GA and I have lots of customers that are into modifing there XJ's. The only downfall I have with the UNI-CHIP is its close to $1000.00 price tag!!!!! wow Time to go bust ass for some dough. Wondering about the whole lean and rich thing? I thought with an automatic FPR that mixture wouldnt be a problem because of the readings of the o2's would tell the pcm to change the input of fuel? Not doubting you but was wondering.
The '00 ECU goes into open loop and ignores the O2 sensor output voltage above 2200rpm at a throttle opening of 70% or greater. Up to 2200rpm, the ECU stays in closed loop even at WOT. This makes tuning a headache that can only be solved with a programmeable chip.
If you shop around for the Unichip, you might be able to find it for a lot less than the $1000 that Hesco charge.
How about A renix based stroker?? Im running low compression for a stroker close to stock with a Ho head and 99 intake a fmp 24 injectors. Modifyed apn header with 2.5 custom downpipe and a magnaflow hi flow cat.. Think it will pass everyone I have talked to locally says no way but After this post my only concern Is how well the renix computer will work with this setup. IM also running a map modifyer if that helps
I have a 1988 renix based stroker, renix head, 60mm TB, 24# injectors, 9.6:1 compression, 2.5" exhaust off a stock exhaust manifold and I passed my e-test easily. I was under 10% of the allowable values.
I don't have a special computer, aftermarket ignition or an adjustable MAP sensor.
How about A renix based stroker?? Im running low compression for a stroker close to stock with a Ho head and 99 intake a fmp 24 injectors. Modifyed apn header with 2.5 custom downpipe and a magnaflow hi flow cat.. Think it will pass everyone I have talked to locally says no way but After this post my only concern Is how well the renix computer will work with this setup. IM also running a map modifyer if that helps
You shouldn't have a problem with the emissions part of the test, but if you have to pass a visual also, you'll fail if the tech knows what he's looking at. The renix computer will be fine for emissions, but not optimal for performance (wide open throttle).
You should have no problem passing emissions with that combination but I recommend that you make sure of that by installing a programmeable computer such as the Unichip and have it custom mapped on the dyno. The '00+ computers on the DIS 4.0 Jeep models are very fussy when it comes to mods.
I guess the Unichip is "emissions legal" in GA? Otherwise you'll fail visual if there is visual in GA and it might set a diagnostic code too.
But definitely the best mod you can do for performance.
I really can't understand why certain mods should cause a vehicle to fail the visual test if the emissions are well below the allowable limits. Don't vehicle inspectors appreciate that some mods can actually improve emissions? I blame short-sighted policy makers for this stupid nonsense.
As Kyung said, the Renix computer can adapt enough for the stroker to pass emissions (provided you have the correct injector size and a functioning O2 sensor) but it definitely won't be optimal for all out performamce.
The same goes for HO computers of all generations. I'm running the stock '92 ECU, 24lb injectors, and MAP adjuster set at 5.10v on my 4.6 stroker. CO and HC emissions are at 20% of the maximum allowable (they don't measure NOx here) and my A/F ratio at WOT is very good except from 4500rpm upwards where it drops to 12:1 and reaches 11:1 by 5000rpm.
You must be making crap power at high rpms Dr. Dyno with an AFR like that. That might mess up some sensors too. I passed my visual as well as emissions, and the guy thought I had an exhaust leak so I got away with that one .
Yeah, my torque does drop off above 4500rpm because of the richness. On the dyno I reached a peak of 198hp at 4650 and I was expecting it to just squeeze in over 200 (I did have 204hp at 4900 with the JET chip installed) but instead, it dropped back to 192hp at 5000rpm and 180hp at the 5200rpm rev limiter.
By removing the JET chip I did gain a bunch of torque from the 1500rpm dyno starting point up to 3800rpm, and peak torque went up from 250lbft at 3750rpm to 254lbft at 3550rpm with the biggest gain of 9lbft coming at 2000rpm (roughly the rpm where my engine spends the most time).
I was happy with the results despite the 4500+rpm drop off in torque because my Jeep feels so much quicker in everyday driving and it's more fun to drive especially with that aggressive throttle response. I suppose that if I corrected the A/F ratios to ~13.0:1 from 4500rpm upwards, I could get back to the 204rwhp I had before removing the JET chip (it was acting up) without losing the torque that I gained at the bottom end/midrange.
_____________________________ The sleeper:1992 XJ Laredo - 4.6L "Poor Man's" Stroker - 5-speed AX15 manual Dyno - 198hp@4650rpm, 254lbft@3550rpm (wheels) = 245hp@4800rpm, 306lbft@3550rpm (crank) Performance - 1/4 mile [email protected] in full street trim Websites -Jeep 4.0 Performance, 4.6L Stroker Build-Up, Dino's Jeep Tricks
Your emissions should be fine. North Carolina used to check emissions and I never had any issues with it. If anything, the stroker was as good or better than the old 4.0L motor. I had a stock 4.2L crank, 4.2L rods, .030 sealed power H802cp pistons, Craptastic Crane cam, Mopar performance head gasket, FMS #24 injectors, and a compression ratio of 9.5 or 9.6 depending on the formula used to calculate it. It would pass emissions with flying colors and no cat. The cat got bashed on a rock and was rattling so I gutted it and put it back in place. The emissions were fine, but the power sucked a big one and it would ping around 3k rpm. I tried the adjustable map sensor but it only moved the whole fuel curve and didnt help out as well as I hoped for. After installing an Apexi SAFC I have a great fuel curve and no pinging and lots of power with no change in emissions. The only problems I ever had with the inspection place and the motor was the intake being a custom heat shield and cone filter. The tech wanted to be a dick that day so I talked to the manager and he ended up passing me after some long discussions and a threat of calling the BBB. They tried to screw me over with "bad winshield wiper blades" and I had a reciept for new wipers purchased the day before. It pisses me off that a business will try and screw you over especially on the stupid little crap. Needless to say, I never went back to that place. The next year and a new inspection place it passed as well with out any issues and the guy made a comment that it was really clean. After he said that I told him it was a stroker motor and he didnt believe me....The solid black marks I left leaving the parking lot just proved that fact Now thats the inspection the shop I work at uses for inspections. Good attitude and business goes a long way, just wish there was more of it these days.
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