I'm really hoping someone can help me with tuning my supercharged 98' 4runner. Almost two years ago I purchased a fuel kit from URD,(Underdog Racing Development),to install on my 4runner. I have had a lot going personally the last two years so it has taken me a while to install the kit mechanically. Since last summer I had finally installed everthing and have been working on tuning the fuel trims. This is where I am having some trouble and frustration. I have followed the instructions provided by URD regarding tuning and it's extremely laborious adjusting each fuel trim by trying to measure where each fuel trim should be. Especially when most of tuning requires having to drive and monitor, and then stop and adjust for each level. I have contacted URD and spoke with Brian. I really believe he has good intentions to help, but frankly has not been much real help. I have even purchased an Aux Box from URD hoping it would help reduce and simplify tuning. However, I haven't been able to use it because I'm unsure how to hook up and use it for the tunining application I intended to be used. I'm really not intrested in knowing each and every nuance on how to how to tune. Frankly, at this point I just want the vehicle to be tuned as the kit is intended to.

Is there anyone who is familiar with the installation and tuning of the kit who can help with a "down and dirty way" to tune my 4runner. What would be ideal is if someone in the Denver area would be willing to tune or at least assist me in tuning my 4runner as the fuel kit was intended to work in the vehicle. I am so close but so far.

 

PM (Mark) Midiwall for help on the tuning.

 

Hey Keith, I got your PM and figured I'd answer in public. btw, thanks Jamie!


So Keith, give me some more specifics about how far you've gotten and what you think that that you're missing - i.e., where do you think you can get to?

Which injectors are you running? I'm not sure what URD was shipping with their fuel kit at that point.

Which pulley are you running on the S/C? Is it stock?

I trust that you did get the Walbro fuel pump installed?

What gauges are you running in the truck? A/FR? EGT? Boost?

What did you expect from the AuxBox? It's generally used as a logger, where it will let you keep track and cross-reference a number of data points, like A/FR, EGT, throttle position, air flow, air temp etc. From there you can tweak to the Nth detail to get things flat. But, it sounds like that's pretty opposite from what you're looking for.

Which fuel/timing unit is this? The SplitSecond FTC1?

Finally... These days, URD is preloading the FTC with a good-start base map. Is this map loaded into your box? If not, then you should contact Brian and get ahold of this map.

 

Hey midi...did you ever get my PM? You could maybe answer that one in public as well

It's mainly about how to know which injectors we can use IIRC. I keep trying to find some high flow intermediate ones and there are plenty on eBay FOR Toyota's but there's no way that i know of to check if they'll fit or how to even know once they are being installed besides trial/error.

If you can share anymore insight into this, please do

Thanks,
Marko

 

I'm by no means an expert at tuning but my truck seems to be running alright and I've tuned it all my self with a driver. If you want I may be able to help you and I live in the denver metro area. PM me and I'll see if I can help you out one day.

 

Ummm, whoops. I don't see anything from you in my PM list, but that doesn't mean I didn't blow you off. There was a lot in there for a while I and may have whacked it with a slew of other stuff. Sorry.

Your quandary is kindof on topic here, at least it's S/C performance related and it sounds like Keith might be able to benefit from the backgrounder as well.


So... are you asking about size or type (high/low impedance) or connectors or just everything?

Size is "easy", if you're talking about replacing the stock 6 with something larger (versus going with a 7th or something like URD's 2nd fuel rail) then figure on topping out at 370cc. Anything larger will be a real pain to get to idle since the granularity of the stock ECU isn't fine enough to shorten the PWM time and get a small spray out of something like a 440cc injector. If you're willing to go with a complete ECU swap (e.g, MegaSquirt), then you can do pretty much what you want. But at some point it becomes overkill.

Connector type... The easiest thing is to not worry about it (seriously) and then find adapter cables like URD sells and wire in a set giving you two heads on the harness. This is what I did with my 370's. It's not pretty, but the other side is fighting with trying to determine if the connectors on the injectors match the stock mates on the harness.

Type... You want "high impedance" injectors, the coils should measure around 13ohms. If you go lower you'll draw too much current out of the ECU and run the risk of burning it up.


Trying to find the right size is a bit of magic and guess work. The first thing you need to keep in check is that you need to have a fuel controller to throttle the injectors. The stock ECU won't be able to deal with much bigger than stock on it's own. The second thing is that you need to make sure that you have a fuel pump that can keep pressure on the rail. The stock pump simply won't push hard enough and you'll have to compensate with longer injector times which shortens the life of the injector and minimizes your ability to tune.

Some of the "magic" side can be handled with math. Something I learned in this process is that HP can be related to injector size through math. It still trips me out, but.. Anyway, hit up this calculator page and start plugging in numbers to see what you should be looking at:

http://www.rceng.com/technical.htm#WORKSHEET


So... Stock injectors are 240cc, a nice jump up is 315cc. As long as you have fuel management (e.g., an SMT or FTC) 315's will handle a normal boost from a SC without an issue. If you start looking at running more than stock boost you'll want to be able to toss more fuel. 330's are a common size that you can get into and still be able to expect a smooth idle. That should be good up through a 2" pulley and headers. Going past that, say with methanol and a port job, you'll need more fuel - now you're into the 370cc range and you need to start expecting to spend a LOT of fiddle time with tuning to get things to settle down.

If you're sidestepping the SC route and are aiming for a street ride, then you're probably looking at a turbo, which means that you'll be able to push a LOT more boost if you wanted to. At that point, I wouldn't bother with looking at larger stock injectors, you won't be able to get good control over the size that you'd need to support 15+lbs of boost. You'll need to jump into something like URD's port injector rail. It's an interesting piece - they're into their 2nd (3rd?) casting now and the initial mechanical issues are pretty well figured out. Running a 2nd set of 6 injectors in that thing will get you all the fuel you could want.


Hope that helps, and sorry again for not answering you before.

 

That is an awesome respone. Before I say anything else, thanks from me and probably every other S/C guy out there for putting your time and your engine on the line for figuring everything out. And don't worry about not getting back to me, it was a bummer at first but I understand it must not be easy to get so many help requests. So don't worry about it, I would never even think about holding it against you.

My plan on the S/C is to complete a similar setup like URD sells except with parts I can get off of eBay or wherever else. Back when I first contacted you, someone had some new injectors up on eBay for a real good price that could push somewhere along 350cc. Now, the seller did state that they could be used by Toyota engines but that's about it as far as info. I tried to cross reference them, but came up with nothing. My main plan is to know if there's a way to know if they'll fit into the manifold physically just by looking at pictures or whatever. That's the first problem that I always come across.

Here's another set of six I found on eBay which I am assuming will fit physically, but how do you know? http://cgi.ebay.com/ebaymotors/Toyot...66130591QQrdZ1

The electrical connection can always be figured out later on...


I know this is starting to get long, but if we're already at it...What is your opinion on not even bothering going with bigger size fuel injectors but just getting the port fueler and letting the ECU control the stock injectors while having an additional device control the fuel porter. Would that be easier (even though a little more expensive) than the bigger injector router. Don't get me wrong, I have read up a lot on this subject, and I understand there might be problems with the injector fighting to get to a 14.7:1 ratio that way. I have read that you guys did figure out how to prevent that with the regular large injector setup but does that solution change with the port fueler?

Lastly, I am very familiar with what is required as far as getting the fuel to the engine and in general with all the parts needed to get things running better with an S/C, but I looked at the URD site and then have two size fuel pumps 190LPH and 250LPH. Is 190 plenty and would it hurt to buy the 250?

Again, thanks for all the help and I hope this thread will eventually evolve into more in-depth detailed info about S/C'ing to help even more people get to their goal.

With that said, my goal is to run 2.2" maybe 2.1 or 2.0" pulleys running perfectly with no lean condition of pinging. It will be tough tuning road, but I'll put a lot of effort getting to that "stock w/ S/C engine" while at the same moment trying to resist the urge to have MORE AND MORE. I know you're having that urge right now midi I hope it's possible...

Well, thanks again for the help now and in advance.

Marko

 

...and that's the way that i did it, and others as well. The upside of this is the learning that you'll do, plus the ability to spread out the cash across time - buying the pieces as you find them. The downside is that you do end up with "many pieces" versus a "single kit" where the components are tried and true with a single support line.


Here's my story on this one.

When I was looking to move up from the 315's, I about choked on the money that URD was asking for the 370s - $510 for a set of 6??? _OMG_ So, I went shopping.

I ended up going with a guy that people vouched for over on CT (CustomTacos). I fired off an email with some questions, he answered quickly, we flipped a couple of more emails, and I paid about $380 for a set of 6 370cc injectors. I was pretty happy.

They showed up quickly, and I tore off the top of the engine to put them in... oh crap, they don't fit. The barrel was too big. I wrote the guy, "oops, I'm sorry, I didn't see that you were putting them in a 4Runner. You can just mill them down". Well, outside of my not really having access to a lathe nor the skills to run it, my statement of "1996 4Runner" appeared in no less than 3 places on the order, and in ALL of our emails. argh. To his credit, he offered to do the work for free, I just needed to send them back. Oh, okay.

TWO WEEKS LATER - I get the injectors back (I'm in Seattle, he's in CA). It kinda' looked like someone had taken a hand grinder to the barrels. SOB. Well, off with the top of the engine, injectors in, engine back on, start it up... spit spit spit spit... I'm leaking fuel from the top of #2 and #4. The O-rings he provided were JUNK. ARGH!

Small town hardware store had a BUNCH of wonderful O-rings. I bought 'em out. off with the top of the engine... blah blah blah.... No leaking, but just before I toasted a valve, I could SWEAR that one of them was sticking. Things just felt weird.

ANYWAY! Long story longer - the point here is that there's a "get what you pay for" moral to the story. When it was all said and done, I would have probably saved enough time and aggravation if I had gone with the RC's from URD to PAY for them.

I did learn something else though - no grinding was required. That's NOT how to get the injectors to fit into your manifold. I learned that the injector barrels/bodies come in different sizes, and they "easily" disassemble so that you can change them out.

argh.


You can ask folks here.

Yes, those will fit. I think those are the classic "green tops" which are 315/318cc injectors. Like I said above, that's a nice comfy size to move up to from stock.

Actually, those have the same connectors as the stock harness.


{cheap plug time}
When you buy used injectors, I STRONGLY recommend you sending them out to be cleaned, tested and flowed. it's an added expense, but the piece of mind is well worth it. I've used Witch Hunter for 3 sets now, and have nothing but great things to say about him:

https://www.yotatech.com/forums/f39/witchhunter-performance-92823/


Umm, I see it as more expensive than a "little more expensive". That rail is a serious piece of work, and outside of paying for it, you're also buying the 2nd set of injectors, which means that you can't recoup any of the cost from selling the stock ones that you'd be replacing. To drive it I think you need the AIC as well. I may be off on that, but I know you can't just piggyback the 6 injectors off of the ECU, the impedance will be off and they either won't fire or you'll burn out the ECU.

Also, the rail won't work with an SC, the design is such that it fits in-between the halves of the stock intake plenum, so turbo only.


As long as we're talking SC (so, not turbo) then the 190 is fine to keep the rail pressure up around 60-70psi for the largest of injectors that you'd be running.

If you're now thinking turbo, and then looking to put more than about 12-14psi of boost on the engine, drop the 250 in there. It'll save you time and effort later.


Well, actually, I keep telling myself that I REALLY need to put together a FAQ. The threads are just a PITA to search when you're not sure what question you're really trying to ask.


fwiw, I would NOT recommend running anything smaller than the 2.2" unless you have some way to cool the air intake. As the SC starts spinning faster (so, a smaller pulley), friction will catch you and start heating the boosted air. That will rob you of power. Moving to a 2.1" or smaller pulley will really be asking you to start running a methanol sprayer order to drop the intake air temp. That will also have a nice side-effect of being a cooling system for the SC - to a point.

The turbo guys get around the heat issue by running an intercooler - this is a device that you push your intake air through in order to cool it down. But, because of how the SC is mounted on our engines, you can't get anything in-between the output of the blower and the engine in order to cool it. So the only thing you can do is cool the non-boosted air which gives you more room to heat it before it becomes an issue.


whew! Another long post!

 

Whoa that's a bunch of info. And yes, a FAQ would definately save you a lot of time, but it would be a huge piece of work. If you ever plan on it, hit me up so I can help because I know quite a bit from researching already.

As for now, I plan to stay S/C only with the 2.2" pulley once I get all the fuel stuff up and running. I have also already decided that I will use Witchhunter if I do end up getting used injectors. Anything else would be simply dumb. So, no shame in the plug there

Wow...I think you have pretty much answered all of my voids. THANKS! The rest is just buying, spending money and tinkering, none which I am directly afraid of, haha.

Last thing though so I don't have to bother anybody again...if I wanted to get injectors now that are > 315 but < 370 do you have any recommendations. Once I get the fuel management setup, I KNOW I will tinker so much and I just don't wanna be limited by the injectors there again.

 

Maybe I'll just put up a wiki - that'll let people add to it as they can.


Basically the list for our engines is 240 (stock), 315/318, 330, 370, 440. So, 330 would be your next step up from 315's, but if you were going to do there, then it might be worth looking at the 370s. You may never use that much fuel, but like I said somewhere above, the 370s will be your last stop before having idling issues.

If it helps, _I_ went to 370's 'cause I knew I wanted to run methanol and move to a 2" pulley. The math said that I needed to run at least 330's to support the amount of HP that I was looking at, so I gave myself some working room. But _now_, I'm looking at pushing even MORE HP (400 crank), and I'm REALLY glad I went with the 370's.

 

I'll start off with the 315's and more up as the need arises...

What are your plans after rebuilding the engine? Are you gonna keep the S/C or go turbo?

 

Not a bad plan!


Oh no, I'm staying with the SC. I like playing in the dirt, and while turbos are getting lighter, thus decreasing spooling time, I want the power & torque at lower RPMs and that only comes from a SC.

 

Great reading.

I have flow tested a good many of the stock injectors for the 5vz, both versions always flow in the range of 240cc. I keep seeing all kinds of different values for the stock injectors and I am not sure where they are coming from, but everyone I have seen is 240cc.

Gadget

 

Yeup, you're right. I had 285 stuck in my head 'cause I was staring at a flow sheet here that had "285" on it. I fixed my posts above.

 

Wow, sorry to hear about your injector ordeal Mark.
Very good info in there though!

 

Peh... that's a pretty normal situation for me Jamie. Nothing "just works" for me, no matter which toy or industry we're talking about.

 

Stock injectors being 240 makes a lot more sense. For some reason, and I don't blame you midi...we all make mistakes, 285 -> 315 seems a lil on the meager side.

S/C is where the fun is at in the dunes, but I really like the customization ability of turbos, but then that's where most of the cost comes from. Having said that I am staying S/C too.

Maybe soon enough we'll find out how low of a pulley you can go to before you blow the supercharger into smitherines. Keep us posted Mark j/k.

 

I PM'ed you about this Mark, but I said I would post it in this thread too in case anyone else has the same question.

As I have said above, I am going to purchase some injectors (315cc) from eBay and after having them cleaned at Witchunter, I want to put them into my truck right away, even before buying the fuel management controller.

My question then becomes, would it be suecidal for the ECU to encounter larger injectors than stock without receiving additional help? I am asking this, because if it's OK I'll put them in to help the engine until I can get a fuel management unit.

Some things I could think of that could go wrong are:
- Could the ECU get confused and lean out too much?
- Would the engine even run?
- Idle?

If no one has an answer, I am not afraid to try it...just wanted to know if anyone else has tried before me.

Thanks!

 

Marko asked me something in a PM, that fits into this thread, so...

The issue with dropping larger injectors in without something to help control them is... you won't have enough control over them. You'll be "okay" in closed loop, but when you jam the pedal, the ECU will switch to open loop and basically just free-run the injectors with whatever the last setting was it saw in closed loop. Given that we're talking about a SC'd engine, then that will more than likely leave you lean up on top, which is pretty ugly.

The fuel management side of something like the SMT or FTC1 will let you add fuel to the engine while you're in open loop, which will alleviate the lean condition and save your engine.

Now, it could be argued that since you're running stock injectors now, then you're already lean up top, so these won't hurt, and should actually help (but you'll still be lean, just not _as_ lean).

The other side of the SMT and FTC1 boxes is of course timing control which is VERY VERY important throughout the power band, closed loop or open loop.

Also, don't forget that stuffing a larger injectors won't do a lot without an upgraded fuel pump to boost the pressure on the rails. You'll want to be dropping in a Walbro 190 as well.

 

Okay, so we're typing at the same time. Lemme add to the above:

1. Could the ECU get confused and lean out too much?
   No, the ECU won't get confused and lean out, but it will eventually hit a max point where it can't increase the injector duration time any more in order to make the A/FR 14.7:1. This will still be a case even with a fuel management system and it's part of the fun of picking the right sized injector for the task at hand.
   
   
2. Would the engine even run?
   Yes, the engine will run.
   
   
3. Idle?
   With the 315's you'll be fine at idle. It may be a bit rich, but it'll run. 330s are "pretty smelly" at idle, and 370s won't idle without management.