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Thread: RE4F03B Automatic with shift kit and Turbo = Success!

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2014-11-21 16:23:00
RE4F03B Automatic with shift kit and Turbo = Success!
So I have had this thread over on G20 for awhile and thought it could be helpful to the sentra guys with the RE4F03B / RE4F03A transmissions also. The car currently has been under boost for 5000 miles and still shifts perfectly.

Here's the new winter project:

2002 G20 Automatic - 135k miles - 1 Owner car - Bought for $450 cash

Story on the car:

Old lady bought this off the lot brand new.... Drove it for 100k plus miles... Her son get's old enough to drive...
Party's in it, trashes the interior and runs it into a pole...
Then sits in the garage for two years with the windows down and getting door dinged to death...

I was just going to part it and use a bunch of parts for my EV0 car but....

I would like to put the myth of auto transmissions on boost being junk to rest. From every automatic transmission failure I have read about
on SR20's sounds like the torque converter or the clutches fail. I have also heard a few people run quite awhile on boosted autos.. I have three good shape auto's and everything to start this experiment.

Should be a really quick setup with the light roller rocker setup @ 9psi T25 ball bearing (should be around 200-220 whp)

The plan:

Fixing the core support / body damage with donor car parts as cheaply as possible. - Cutting out on thanksgiving vacation time...

Wire in AEM management - Done and installed


Pull valve body - Done

Install shift kit - Done

Order Level 10 torque converter - Skipped

Install big tranny cooler - maybe a tranny temp gauge - Still need to hit pick-n-pull

Bone stock 135k roller rocker - Keeping all emissions, egr in tact but deleting the manifold/cat converter. Done
Going with a 99' cat or welding a bung behind the second cat.

Tap engine block for oil drain - Done

Install Avenir W11 BB T25 setup (9psi) - Sitting in garage 40k mile JDM pull from my brothers setup - Done

Install our avenir to stock exhaust system downpipe - Done

Install FPR and set to 4bar fuel pressure - Going to wait and see if 3 bar maxes out

I can't say that I have ever seen anyone put in a built torque converter and shift kit in a G20 yet. And to be honest I would like to have a car my girl will drive.

I want to hear your opinions good or bad

Well I'm back to work on the automatic car until the twin disc clutch comes in for my DD. James helped me all Saturday on the transmission. Shift kit is done and back in the car. I also worked on the core support and got it all fixed. I'm going to weld it in this week after I get off work. Now I just have to bolt the turbo stuff on and some body parts. Also going to re tap the water drain to NPT and make my own lines. I'll get more pics of the front end finished up....

The core support that I salvaged from the 2000 was rusted really bad on the bottom so I decided to cut the bottom half out and use a aftermarket lower. Still needs some welding but it's getting there.

Got motivated last night and got primer on the bare metal, turbo/manifold tapped with fittings, made solid front motor mount, made the water return hard line, installed alt and a/c, also tapped and made egr hard line setup. The hard work is all done. Just some reassembly work and intercooler install.

Worked some more last night. Got the whole exhaust sealed up. Finished the oil feed, water feed. Deleted the throttlebody water lines. Tapped turbo compressor housing for boost reference. Trimmed the Avenir heat shield for EGR line.

Getting real close to starting the car up. Lined up all of the intercooler piping, mounted the intercooler, cut the flange off of the MAF, lots of little things put back together... And yes it is going to be a blow through just like the other 2 cars

Got back to work on the auto car this weekend. O2 #1 and #2 wiring extended, BOV welded to intercooler pipe, all fluids are back in.. All of the hard work is DONE... Lots of little things to finish up and need to get it legal now..

I got a hood on her last night and drove around on the stock ECU. Can't get on it too hard without a MAF CEL popping. Everything seems to run really good, no leaks, runs and shifts great. As soon as I get the old gas run out of it and a AFR gauge installed I will plug the FIC on it and start tuning.

Mileage at time of turbo/shift kit install : 135323 Miles

Well I got 130 miles on her with the factory computer. I didn't have time to get the wideband in and start tuning since my girls Sentra SE 2.0 started shifting hard and threw a solenoid CEL. I ended up throwing in the spare 68k mile transmission from my other G20 part car since hers has 162,500 miles and we are getting ready to take a 2000 mile trip in it. It's nice to feel the difference between the new stock transmission (Sentra 2.0) against the G20 with shift kit. The stock 68k tranny glides in really smooth every gear and the shift kitted G20 is really firm and quick to shift. I'm going to try to get the wideband in this week in between things (just got my DET/VE stuff in) so we can start tuning it.

We got it tuned pretty good last night. From the AEM it looks like about 8.5 PSI peak stock Avenir W11 actuator pressure, I still need to get a good boost gauge in it. The stock injectors @ stock fuel pressure are doing the job also. Was running really bad when we started last night so we pulled the plugs for the first time and found crappy champions gapped @ .050 in it. We put a used set of BKR6's gapped @ .030 and it ran soooo much smoother. The only code the 32bit ecu will throw is a MAF error if I get on it really hard and let off really fast. We are going to play with the MAF placement and MAF tables in the FIC to try and fix that. It's been a fun build, simple and quick. Currently 330 miles on it. Time to put some real miles on her now....

2002 Infiniti G20 stock 32bit ECU with FIC6
Stock automatic with transgo HD shift kit
Avenir W11 BB T2 turbo and manifold/jpipe
AEM 4100 Wideband
3" SS downpipe and 99' G20 full size cat
27"x10"x3" Intercooler
2.5" Intercooler piping

Stock MAF, Injectors, Fuel pressure regulator, Fuel pump

Had a problem this weekend. Was pulling out of the neighborhood and it didn't shift hard and I got out of it as soon as I felt it. Got on the highway and noticed smoke rolling out behind the car. Pulled off the highway and it started falling in to neutral on me. Got to a gas station and found that one of the stock transmission cooler lines blew.. Sat in the lot for 45 mins patching it up and found that I lost 1.5 qts of fluid when I filled it back up. Seems to be ok but I guess we will see. Sitting @ 500 miles now. Found out this morning that it can walk a Caddy CTS pretty hard, must have been the 6 cyl

Other things finished on the car:

Cleaned the interior up
Replaced A/C O-Rings
Installed used condenser
Oil & 134 Recharge
50 degree cold air now!

Transmission has been going strong and the only problem has been the tranny line splitting open. I got a cheap $15 boost gauge and mounted it with the AFR under the radio in the cubby hole. Just driving it everyday while getting the other G ready.... Also I was off on the boost. It's getting 7.5ish PSI at night when it's cool out and 8psi in the mornings when it's warmer. Probably 190-200 WHP maxed stock injectors @ factory fuel pressure.

Video of the gauges here:
Harbor Freight 98478 $17.99 Nitrous boost / vac gauge test

Was playing around with the FIC6 datalogging and saw that it was running pretty lean up top. Decided to convert the car to 440cc EV6 Bosch injectors since they are really cheap. Only thing I had to do was make spacers (stacked washers) since they are a little taller and solder EV6 connectors to the injector harness. Project took me 2 hours to install injectors and solder connectors. Didn't have to pull intake to do this. After the install I just went into the aem software and did a injector change from 306cc to 440cc and boom runs great! We still need to do fine tuning so the top end is right because the 306's ran out over 100% so we couldn't tune anymore.

More playing around with Virtual Dyno and FIC6 data. I edited the text that comes out of the FIC datalog with excel and got a rough virtual dyno. Was disappointing but gives us something to work with. this is before I changed the stock injectors out.

So I figure 175HP @ flywheel (conservative not knowing auto/tq converter loss) and the log shows it's only getting 6.5psi at the AEM unit - Gauges are showing 7.5 to 8.0psi... Stock W11 avenir @ 9PSI was 227 FWHP so we have a lot to go

To be honest this could be wayyy off since editing FIC text and moving it to VD may or may not be very accurate?? But it will give us a base HP/TQ to start with. Going to log it again now that the 440cc are in and can be fueled up top better. Wondering if it was running so lean up top that the knock sensor started pulling timing maybe? Also going to pull the exhaust after the cat and do a log to see if there is any difference. stock chambered muffler and small ID piping may be a big restriction?

4000 miles now! The car really needs some more tire under it, I have to try and pedal it through 1st gear. Guess I can't ask too much out of 195's and a non LSD tranny Did a quick stop and launch to 60mph in the video today. Not sure how many more miles I'm going to push this tranny since we just finished up another with new clutches and HD shift kit...

Finished up the exhaust! 3" stainless all the way even the cat converter. JamesJv0 spent most of Saturday welding everything up for me. The cars stock catback is less than 2" ID in the bends and the stock muffler is horrible. I could tell a gain in the high RPM area right away and the boost has gone up too! Taps 9psi like it should on the stock Avenir actuator. Put her in the garage this week to fix a oil pan leak and while it's in there I'm going to throw in the AEM FIC8 and a boost solenoid so I can flatten out the boost and maybe raise it a bit Gotta pop that auto so I can try the new one we rebuilt right?

Edit: Now that the mornings are really cold and in the 40's she taps 10psi and falls to 9psi - Get's solid 8psi on hot days. Exhaust made +1 psi gain

We had our last track day this weekend and I rushed to get both G20's out there since so much has changed with them. The 2002 auto last 1/4 mile ran a best of 15.40 @ 89.20. We pulled the stock exhaust and put in our 3" stainless with a 3" cat converter. Also changed the stock RR injectors out for Bosch 440cc units because we needed more fuel after the exhaust. Pulled a 14.5962 @ 94.78 and was holding 8psi. It took a new Hyundai Genisis 2.0T 6 speed by brute horsepower. The Genesis got the jump in reaction and a better 60ft. Not too bad for a autotragic car..

Last edited by Y2KG20 on 2014-11-21 at 16-24-20.
2014-11-21 16:53:10
Nice, my B15 auto trans lasted about 3 years or so. Finally lost 1st and R one day after a couple months on a GT28RS at 14psi on a low compression VE-T. Decided to swap to manual.

Trapped 99mph in the 1/4 mile (7psi, switching to 14psi at about 1000')

I manually shifted from 2nd for 2 years or so, to rev the car out.

Had a G20 LSD Auto trans being built, but the builder had issues and later passed away. Was installing a shift kit, solenoid group, and some other transgo parts. Never got to test it, and not sure what happened to that transmission.
Last edited by mirrortints on 2014-11-21 at 16-55-05.
2014-11-21 17:28:16
2014-11-21 18:40:44
@ Mirrortints - That's good info, do you have any idea how many miles you put on the tranny before jumping to 14psi? We built another transmission so we could push higher boost. The only thing I wish we did was add some extra clutch discs, but I only had I rebuild set

Here is #2 rebuild - Not in the car yet...

We just built transmission #2 this weekend for the 2002 G20 with avenir turbo setup. The first build was just a Transgo shift kit in a stock 135k RE4F03B and stock boost. It has been holding up for 4k miles so far but we want to push the car to 14-15psi and better flowing exhaust and with the high mileage we figured we were pushing it already.

The build starts with a 2000 RE4F03B that had 165k and started to throw a trans code from slippage. We installed a new clutch and friction set, also some seals and a new Transgo shift kit. It's the first automatic we have ever been into so hopefully everything works out well. We did find several clutch packs that can be sorted for more clutches by removing double friction plates just like our old lockers in the mustang rear ends but we didn't have parts to try it out this time. If this works out we will probably build #3 with a VLSD unit from one of the parts cars and add more clutches. Start to finish took my brother and I 8 hours to complete.

Other things that may be added are port pressure and temp gauges to monitor line pressure. and external cooler depending on the results.

The first pics are going to be part of the Transgo shift kit install that is optional. You have to take the bellhouse off and remove the top 3/4 gear drum to install a problematic seal that is a common problem.

That's all of the inner seal shift kit install pics that I took ^^^

Slide show of all pics

Slide Show
2014-11-21 19:02:32
I put approximately 10k miles at 7psi, and 4k miles at 14psi. The car had about 60k miles when first turbo'd.

Never slipped or anything. Only a couple hundred miles after ve-t swap.
2014-11-21 19:04:22
Good luck with the build! I was tired of hearing kujoo deterring everyone from auto and turbo.
2014-11-21 19:22:26
This is awesome stuff!
2014-11-21 19:40:46
Thanks man! I just noticed it has been a year since I started building that car. I've been done with it for awhile and my buddy is currently driving it to keep the miles racking up. When I get time I'll probably throw my FIC8 on it so I can control the boost by RPM and spin that little T25 @ 14psi and see how long the clutches last. I bet they won't hold up too long with 140+ thousand miles.
Last edited by Y2KG20 on 2014-11-21 at 19-42-21.
2014-11-21 19:59:54
Not sure how in-depth you will go. But ever think about adjusting the auto ecu (or whatever the tranny computer is called)?

Something like this: SSv4
2014-11-21 20:23:49
I doubt I will mess with the transmission control. If I wanted it to shift harder I would probably start with the valve body or pressure lines. But so far it has been shifting hard @ 9psi (10psi in cold weather). If I get any glide @ 14 PSI I may get into it deeper. I am also curious about the valve body differences. The 2002 valve body was a little different than the 2 other 2000 valve bodies that we took apart and kitted. If I get the rebuilt 2000 transmission put in the car I'll post if there is any shift firmness difference between the two (2000 vs 2002)VB's.
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