If you're happy with half way tuning the truck since you'll never drive above 5K, then that's your prerogative. Personally I want to know I have it right.

You're already showing lean at 3500 RPM and 6.5 psi. You need to be below 12, not at 12.5 or above.

You can not control stock injector duty cycle at all directly. The injectors will spray fuel trying to get to 10.X AFR in open loop. My stock 4Runner went to 10.2 at WOT and open loop.

Your truck is seeing 12.5 at 6.5 psi and 3500 RPM. In those cells you need to put in a 1.2 to try to get it back to 11.8 or there about. That will also take some stress off the stock injectors since the stock O2 sensor will see a lower AFR and not have to tell the stock injectors to try so hard.

 

Isn't the ECU ignoring the o2 sensor in open loop? If it is then adding more gas on the 7th will just lower the AFR but not reduce the load on the stock injectors. Unless I'm missing something??

I could lighten the load on the stock injectors in closed loop by adding fuel with the 7th, but then when I hit open loop I'm way rich in those cells. I'll do some more tweaking, but honestly it seems good with no 7th.

 

Open loop vs. closed loop is a little bit of black magic and highly dependent on the parameters Toyota programmed into the ECU. I'm honestly not sure if the O2 sensor is ignored, or if the 14.7 AFR parameter is ignored when in open loop.

You're NOT good now with it being at 12.5 AFR and 3500 RPM 6.5 psi. What data are you looking at that is making you think it's OK without the 7th?

EGTs could be, and likely are, getting pretty toasty at that AFR in a 4Runner. Keep in mind this isn't a light weight sport car and it takes more engine effort to push it down the road.

 

In the last movie, I'm sitting at low 12s and high 11's at high boost. If I enable the 7th in those cells, I get low 11's and high 10's. I'll do some more runs, and let you guys have another lookie see. Should I be shooting for 11.8 or lower? I guess my idea of lean was more like 15 not 12.5.

On a side note, I got the LoTek 2 guage pod holder thingy for my boost and AFR guages. Its OK, but not great. I'll toss up some pics of it.

Also, I'm kind of bummed I'm only getting 7PSI with the 2.2 pully. Could that be because the SC has 90K on it? I'm contemplating milling it a tad bit.
Speedy, I think you are right that maybe if I get the boost where it should be I'll be seeing more need for fuel mods.

 

That is strange, I did one test drive last week and I got into a 10.5 psi cell with the 2.1" pulley.

 

For forced induction in a vehicle as heavy as a 4Runner you should shoot for 11.8. Anything over 12 is really too lean for this application. The reason is exhaust gas temps. They tend to get quite high over 12 from the testing I've seen, although I didn't perform any EGT tests myself, so I'm going from other reports on that. I will say that on the dyno my 4Runner made the best power right at 12 on the AFR gauge and dropped as much as 20HP once it went over 12.

I did some more thinking on the way to work regarding open loop and injector duty cycle. When I had my OBDII BR-3 hooked up and would hit open loop my fuel trims would just freeze. I know for a fact that in open loop the ECU is no longer trying to attain 14.7 AFR, but there has to be some programming to keep it from just spraying fuel at maximum capacity.

It's very odd that you're only seeing 7 psi with that 2.2 pulley. Have you verified there are no leaks around your boost gauge or connection to the SC? Have you measured the pulley with a micrometer to make sure it is in fact 2.2"? Having 90K on the charger could account for some of it. The usual recommendation is to have the charger refurbished by Magnuson after 60K miles. I think the cost for that is $750. They replace the nose drive and some bearing and what not I believe.

Let's see a WOT 4th gear run starting from about 40MPH and hold it until the speed limiter kicks in or the rev limiter. Then we can make some determinations on how you're sitting.

How many miles do you have since tuning the timing? In my experience that also affected my WOT AFRs as they got leaner after the ECU learned the new settings. I went from high 10s to high 11s after about 200 or so miles.

 

http://s114.photobucket.com/albums/n...urrent=hh1.flv

Ok, I did a run this morning, up a big hill on the freeway, going way to fast with other people on the road

3rd gear hitting the rev limiter at 5500RPM. Still looks OK to me. Even rich at some points. Sorry its jumping all over the place, the rev limiter keeps me from holding steady. Then at the end I hit 4th gear and went some more...

 

I think you need to do this in 4th. You're at 5500 RPM but you're only at 3-3.5 PSI. Yes you are good in those areas, but the PSI needs to get on up to 6 or 7 at 5500 RPM to know what's going on. It'll also not bounce off the rev limiter as fast and you'll get a better view.

I did see one area where you got to 4000 RPM and 6 PSI and that was also good, but I never saw 6.5 - 7 PSI and 5000 or more RPM.

Have you checked the SC bypass valve to make sure it's set properly? It's that canister dealio on the back of the SC. The pressure you're showing now is what it would be with the stock pulley. I'm wondering if your bypass valve is set funny losing pressure.

My truck was fine without the 7th using the stock pulley. Once I added the 2.2" I need more fuel.

 

I'll try and get another run in 4th soon. I've been doing them on the way to work so I don't go out and burn gas.

How do you check the bypass on the SC? I know what you are referring to but not how to check it.

 

There is a nut/screw on it that can be adjusted so that the bypass opens up earlier than it should. My buddy did this to limit his to 5 PSI before he had fuel mods. I've not fooled with mine, but I'm confident you should be more than 6.5 PSI with that pulley. Give URD a call and ask about it, especially since you're at sea level. They can tell you how to check it I'm sure.

 

Hi,

I'm really new to all of this and I'm buying a 2003 tacoma with a TRD SC bolted on. It looks like it's only putting out a max of 6lbs of boost from the guage. The truck still has the stock fuel injectors, and fuel pump. Do you all think that this is going to be ok or will I have to do the remaining upgrades that you are talking about in regards to fuel. It is a standard.

Thanks

 

What part of the country do you live in? What's the elevation?

From my experience with the stock pulley the fuel side of things will be fine, BUT you will need to address the timing to get rid of the ping which is terrible for the motor.

Now, having said that, since you're already going to have to fix the timing, you might as well get the 7th injector kit with a smaller 2.2" pulley and just knock it out in one shot. The kit comes with a piggy back that will adjust timing AND control the extra fuel for the 2.2" pulley, a thermostat, and cooler plugs, and fuel pump just in case you need it.

With the 7th injector kit and 2.2" pulley plan on an additional 30 - 40 HP over what you have now to boot.

If you are 100% happy with what you've got then call http://www.urdusa.com/ and see if they just have a timing calibrator to sell separately with an integrated AFR Calibrator, install and you're done.

 

Hey thanks a lot. The timing issue has been done already so there is no ping at low rpms. I live in Colorado at 8000' hence the need for the SC. I haven't purchased the truck yet and haven't heard or seen anything about reliability issues.

 

What's been done to correct timing?

 

The higher you go in elevation the less boost you'll get, and less need for fuel mods. I'd say (as long as you don't have pinging) you'll be good with a stock pulley and no fuel mods @8000 ft.

 

I've been doing my 44 mile a day commute on my street bike but have been taking the tacoma out dirtbiking regularly in the past couple months since putting the URD kit in. I am still running really good without the 7th hooked up. Timing adjustment is working well, and the 2.2 pully doesn't seem to be doing much. I'm going to have the SC rebuilt at some point by magnusun and see if they can get my boost up a bit with the 2.2.

Just thought I'd bring this thread back to life and give you guys and update.

Also, one Q for speedy. Do you ever have your AFR guage go off on you and have to reset it? I've had to reset mine several times now. I just do a reset on it with the button and its fine again, but it is a minor annoyance.

 

My A/F gauge has only had the original free air calibration when first installed, but it always settles on 14.7 so I guess its right on.

 

No, I've never had that happen with my AFR. Having the SC re-worked would help with the boost I'd think. Mine gets quite a bit more than yours with the 2.2" pulley.

Make sure you have a really good chassis ground on that LC-1. That might be your problem.

With gas being ridiculous now, I commute mainly in the Honda Accord and save the 4Runner for weekends only. Such a shame. I rode my CBR1000RR to work yesterday even. If I take it easy on the throttle of that beast it gets 40+mpg.

 

hey bringing back the thread again. Not really a SC question, but have you guys ever adjusted your valves? I was thinking about checking mine out since its got 100K miles with the supercharger on it now. I'm assuming they are still in spec since the truck runs so smooth. But I figure if the motorcycles and the honda civic my lady has all need adjustment now and then the truck probably does too. But I'm just not sure if the 3.4 would even need it at 100K.

 

Only one way to find out, measure the clearance. I hear they are a PITA to adjust though. They require shims that are expensive, and you have to order them and its hard to know what shims you need before hand.