Lexus IS Forum banner

121 - 140 of 155 Posts

·
Registered
Joined
·
26 Posts
I have external tranny cooler plumbed in after the stock radiator cooler. It was probably $40 max. That’s it. My tranny has 200k on it and it does do some funny shit sometimes when trying the shift gears at wot. I’m unsure if that’s due to the higher mileage or the 4.1 gearing plus extra horsepower confusing the trans computer. It hits the rev limiter sometimes before it shifts. It sounds cool as hell but it’s not the fastest way from point A to point B. I’m planning to drop in a lower mileage stock auto trans. I’ll do the valve body upgrade on that trans before I toss it in.
 
  • Like
Reactions: toneekay

·
Registered
Joined
·
142 Posts
I have external tranny cooler plumbed in after the stock radiator cooler. It was probably $40 max. That’s it. My tranny has 200k on it and it does do some funny shit sometimes when trying the shift gears at wot. I’m unsure if that’s due to the higher mileage or the 4.1 gearing plus extra horsepower confusing the trans computer. It hits the rev limiter sometimes before it shifts. It sounds cool as hell but it’s not the fastest way from point A to point B. I’m planning to drop in a lower mileage stock auto trans. I’ll do the valve body upgrade on that trans before I toss it in.
Definitely could be the uber high miles. I'm at 252K right now, all stock everything except for the 4.1 and it shifts funny.
 

·
Registered
Joined
·
7 Posts
Hello all! Awesome to see this thread is still alive! Just read it from top to bottom! Ive known I wanted to turbo my is300 but have been tossing up what I want to do for engine management... Standalone, piggyback, modifying my harness to accept a jzs161 ecu.... And I think you've just convinced me to go boos first, management later!
 

·
Registered
Joined
·
7 Posts
This thread is what inspired me to start my build. It has proven what I already suspected. You can make safe,fun, and reliable power for well under the 10k everyone claims it costs to boost an is. Just don’t get greedy and stay within the limits and you should have some long lasting fun. I came in at around $1750 not including my exhaust system.

What exhaust manifold are you using if you don't mind me asking? Really like how it sits
 

·
Registered
Joined
·
81 Posts
Discussion Starter #126
Transmission mods wise I've got the Accumulators shimmed up by around 12mm each, my shifting still sucks. My 1-2 shift will slip if I don't let off the gas as it's changing, but I can hold power in all other gears without it slipping at all, this was when I was at 9 PSI though (Before the catastrophe). My transmission has 83k miles on it, the only other weird thing that happens is when I'm coming to a stop and the transmission shifts into 1st, then it gives a slight jerk, but that's about it. I don't have a trans cooler at all.

Also, that's awesome to hear that your trims are still holding up @Driftin8ez

Welcome to the stock ECU club @NZ-IS300
 

·
Registered
Joined
·
26 Posts
Got bored today and decided to switch my o2 sensors around to see what difference it makes if any. The picture shows my new setup. Previously I had S1 and S2 right next to each other in the lower part of the down pipe and the wideband at the top right next to the turbo. I might have to par the heater wires with both s1’s on the same sensor with this setup which leads to other problems but we won’t know until I try.

 

·
Registered
Joined
·
943 Posts
Transmission mods wise I've got the Accumulators shimmed up by around 12mm each, my shifting still sucks. My 1-2 shift will slip if I don't let off the gas as it's changing, but I can hold power in all other gears without it slipping at all, this was when I was at 9 PSI though (Before the catastrophe). My transmission has 83k miles on it, the only other weird thing that happens is when I'm coming to a stop and the transmission shifts into 1st, then it gives a slight jerk, but that's about it. I don't have a trans cooler at all.
1-2 is always a problem on these A650 trans, you can shim the other shift solenoids relatively easily, but as i understand it the 1-2 shift is controlled by the line pressure so without some more hefty know how modding drilling out the holes in the (accumulator??) plate all you can do is set that adjuster on the side of the accumulator to max and hope for the best. Not sure if there are any additives that might help, mine must have had some different trans fluid or additives when i first got it as it shifted hard until i did the first trans oil change. i thought i had broken something in the process when i did the first drive after the service lol
 

·
Registered
Joined
·
7 Posts
So correct me if im wrong but if you installed say 440cc injectors would the fuel trim compensate and dial it back so that it will still run well and not be pushing the injectors so much, so they are less likely to die from running at such high duty cycle all the time?

Also is it possible to shim the gearbox with it still in the car? Would be bit of a pain doing it upside-down but possible?
 

·
Registered
Joined
·
943 Posts
Also is it possible to shim the gearbox with it still in the car? Would be bit of a pain doing it upside-down but possible?
possible yes, but a bit of a PITA. I did mine on the ramps at home, definitely need an extra pair of hands getting it all back in and not a job for the faint hearted. I wouldn't attempt unless you know what you are doing.
 

·
Registered
Joined
·
81 Posts
Discussion Starter #131
So correct me if im wrong but if you installed say 440cc injectors would the fuel trim compensate and dial it back so that it will still run well and not be pushing the injectors so much, so they are less likely to die from running at such high duty cycle all the time?

Also is it possible to shim the gearbox with it still in the car? Would be bit of a pain doing it upside-down but possible?

I think maximum fuel trim compensation is 25%, so if you run 440cc's at 20 PSI fuel pressure then you would be safe, but your fuel atomization would be absolutely poop.

Also, as with PNUT, I did mine on stands as well. Had to use a jack with a piece of wood on top of it to push the VB back up by myself. I also did it twice in one week because I chickened out the first time and only shimmed the accumulators up by like 6mm
 

·
Registered
Joined
·
26 Posts
Same results on new o2 setup ? I will be wiring in my ecu “black box” this weekend.
 

·
Registered
Joined
·
7 Posts
I've been doing some looking around and there's a unit made by split second which when boost comes on it sets the ECU into open look mode, ignoring the O2 sensors and calculate fuel on airflow, throttle position etc... This way the ECU will not apply the boost fuel trims to the long trim map....
Seems like an interesting idea. Do you have any thoughts?
 

·
Registered
Joined
·
81 Posts
Discussion Starter #134
It might actually be cheaper just to get a Megasquirt 2/3 and run it on that perhaps.

Also, I think I've found a buyer for my GS300 so it looks like I might be out of the NA-T business :( But I will still be around to discuss and learn and see everyones progress.
 

·
Registered
Joined
·
1 Posts
Ive been keeping up with this whole thing for a while now and just decided to register here to give some input. Regarding the o2 situation, why not leave the B1S1 and B2S1 either wired together or separate, then take the B1S2 and B2S2 and wire those together or leave them separate and just use a spark plug defouler in an additional bung in the exhaust? Ive read about people with aftermarket headers having success with this in keeping the cel off and this worked for a subaru I had in the past. This is something Ive been considering doing in addition to whats already been done in this thread. Im also curious, theres a guy on youtube "C3garagemedia" who boosted his IS w/ the entire CXracing kit, aftermarket injectors, and the AEM fic + boomslang harness and I think he was pushing the limits of the otherwise stock fuel system at 5.4psi (approx 300whp). not sure if that info is of any use but maybe something to consider. Regardless, appreciate all the info that was brought here, Im for sure going this route in the near future (03 IS 5 speed) until I can save up enough to get a standalone or piggyback. :approve:
 

·
Registered
Joined
·
13 Posts
Hey guys,

Did pretty much the same build on my 04’ IS300 with;

-Walbro 255
-MKIV N/A injectors (330cc)
-water/meth injection
-all supporting gauges (A/F, oil pressure, boost).
-CXRacing NA-T kit
-Precision 46mm wastegate.
-Oil catch.
-BC 264 cams.
-4.5 lbs boost
-Stock GE VVTi internals.
-external trans cooler.

Ran that for about 2k miles. Super rich A/F ratios, and I had to empty my catch about once every 2 weeks. Fun, but A650 had the typical delay in shifting which caused a bad over boost situation at redline.

Upgraded to:

-AEM Infinity 6
-Tweak’d Performance wiring harness.
-525cc FIC injectors
-Fuel pressure, ect, oil pressure sensors (AEM).
-3 bar MAP (AEM).

Tuned by Vlad. Super safe tune (334rwhp/278rwtq). 8lbs boost. Running great.

Fun on stock ECU, but scary and burns crazy fuel. I’m not worried about emissions at this point, fortunately. Plus the overboost situation is not good for anything. Might be because I had too big a wastegate (the CXRacing kit comes with 44mm)? But I thought the more flow you need to pass the bigger the wastegate...

Any case, goin strong. If you’re having luck in the stock ECU, more power to you. Guess our USDM ECU/TCM is just garbage at handling boost.
 

·
Registered
Joined
·
23 Posts
Hey guys,

Did pretty much the same build on my 04’ IS300 with;

-Walbro 255
-MKIV N/A injectors (330cc)
-water/meth injection
-all supporting gauges (A/F, oil pressure, boost).
-CXRacing NA-T kit
-Precision 46mm wastegate.
-Oil catch.
-BC 264 cams.
-4.5 lbs boost
-Stock GE VVTi internals.
-external trans cooler.

Ran that for about 2k miles. Super rich A/F ratios, and I had to empty my catch about once every 2 weeks. Fun, but A650 had the typical delay in shifting which caused a bad over boost situation at redline.

Upgraded to:

-AEM Infinity 6
-Tweak’d Performance wiring harness.
-525cc FIC injectors
-Fuel pressure, ect, oil pressure sensors (AEM).
-3 bar MAP (AEM).

Tuned by Vlad. Super safe tune (334rwhp/278rwtq). 8lbs boost. Running great.

Fun on stock ECU, but scary and burns crazy fuel. I’m not worried about emissions at this point, fortunately. Plus the overboost situation is not good for anything. Might be because I had too big a wastegate (the CXRacing kit comes with 44mm)? But I thought the more flow you need to pass the bigger the wastegate...

Any case, goin strong. If you’re having luck in the stock ECU, more power to you. Guess our USDM ECU/TCM is just garbage at handling boost.
How did those 330cc injectors hold up?
 

·
Registered
Joined
·
13 Posts
Feet,

The 330cc injectors worked fine. Direct plug n, play for our cars. Not sure what duty cycle they were at, but at 4.5lbs I couldn’t have been pushing much more than 275 to the wheels, if that.

I still have em if you want em. I only put maybe 2500 miles on the em. Only reason I switched to the 525cc is because my tuner recommended it.
 

·
Registered
Joined
·
23 Posts
Feet,

The 330cc injectors worked fine. Direct plug n, play for our cars. Not sure what duty cycle they were at, but at 4.5lbs I couldn’t have been pushing much more than 275 to the wheels, if that.

I still have em if you want em. I only put maybe 2500 miles on the em. Only reason I switched to the 525cc is because my tuner recommended it.
Still debating if I want to go with some 330cc or 440cc injectors. I have a 5 speed W55 and don't want to push past 300rwhp. Just curious, how much for the injectors?
 

·
Registered
Joined
·
13 Posts
Feet,

With the W55 manual (even with a clutch upgrade), 300whp is really pushing it. Those transmissions are glass and its just a matter of time before that trans lets go. However, swapping in some other kind of manual (R154, V160, CD009) will be a bit easier for you (but not cheap).

The 330cc injectors will hold fine at 300whp, and the stock ECU will be able to adjust for them. It will not be able to adjust for 440cc. You will need some kind of engine management to compensate.

Honestly man, considering how much just a trans swap alone would cost you I would strongly consider just doing a GTE swap. If I could go back and do it all over again, thats the route I would have gone. An Aristo engine, trans, harness and ECU can be had for about $2900 with shipping. However, there is a bit of other modification that will need to be done to make it work.

Many options out there.
 
121 - 140 of 155 Posts
Top