Hameed

Yes, this may sound like a stupid question..........

What exactly is the process involved with tuning a GS400's engine for optimum air and fuel ratios to take advantage of better breathing characteristics that the following mods allow:
- a bigger intake such as the K&N FIPK
- a more freely flowing exhaust
- headers

I want to know what the process involves, and if this can be done without a permanently mounted unit such as an Apexi SAFC II that adjusts the air fuel ratio for just(?) the intake.

What I am trying to figure out is if I can walk into a shop that specializes in tuning engines and get my car tuned to take advantage of the K&N Intake and the new exhaust, without necessarily having to buy an Apexi SAFC II.

I am not trying to save money by not buying an SAFC, I just don't want to have to install another gadget in my car that will only be used once initially and then very likely not be touched again or even if it is, probably only one or two more times.

I want to call some shops and ask them but am concerned that they will (or not) say that they can tune my car's engine just to get my business and not necessarily have specifically tuned a GS400 engine before. I just don't want some incompetent to mess with my engine that's all.

RMMGS4

iTrader: (5)

Hameed,
Only have a little time to respond before work. I can add more later.

Basically you don't "Need" tuning in this combination to have a proper running car. You "need" tuning if you are trying to optimise the performance of this set up in order to squeeze out the last drops of HP. If that is your intent then the SAFC will just be another device that adds some HP to your set up. In that respect it is just like any other performance mod.

With regards to the A/F ratio with this set up, basically I can tell you with these mods the A/F will still be within a reasonable and safe range. For more extreme mods like high boost FI, this would not be the case. In that case you definitely NEED to tune in order to get the car to run properly as well as adjust the AF to a safe level that will not allow damage to your engine under various load conditions.

Since you are a car audio (SQ) techie like my self here's another analogy.

If you mod an audiosystem with varying speakers, install locations, etc, you will have a complex acoustic environment to tame. This will require an equalizer to flatten out the curve of all the peaks and dips.

In the case of the engine set up in question,and relating it to the above example, well your frequency response is quite flat with no serious peaks/dips. So an eq is not really "needed".

You could add a 5 band eq (SAFC equivalent) to tune it for a little better performance, but the gain will be small.

Back to that hi boost FI set up. There the freq. response is erratic and quite complex. This will require either a 1/3 octave 32 band eq or perhaps a 5 band parametric in order to tame this curve. (motec equivalent)

Bottom line is the SAFC is good for a few more HP with that set up, but the car will run safe and fine without it since the balance of the AF ratio will not be greatly affected. If you want to "fine tune" the A/F , then the SAFC will be good for roughly 5 -10 hp at best.


I am typing right out of my head so trying to go back now and proof read my response is limited right now.

Hope this makes sense. If not I'll correct it later . Tonight.

Hameed

Thanks Glen that makes perfect sense.

1. I do want to gain the extra 5 or so HP that the SAFC II will allow.

2. So I guess what you are saying is that if I want to gain that extra HP, I have no choice other than to have an SAFC II installed in the car. (great analogy to the EQ )

Thanks!

RMMGS4

iTrader: (5)

Well performance has its price. Currently the mods we are performing are costing anywhere from $70 to $100 for each HP gained. We are all looking for the best bang for the buck. The SAFC is on the mid level of the HP per dollar scale, and the header mod is on the higher end.

Your x pipe mod is probably in that mid-range as well.

These are all easy bolt on type mods. so in that respect the easiest power adders (Nitrous is the exception).

Back to the SAFC for a moment. I think we need to do some long term testing with the SAFC set up we are currently evaluating up here in NorCal. There are some unknowns that I want to look into, so I am not fully sold on it's merits until we look into that. This will take some time.

Also there are other options to try besides the SAFC. Most of them cost much more, so again HP/ dollar factors in.

Stay Tuned

Dx3

iTrader: (13)

Hameed,

The SAFC is a very cost effective way to get those extra horses you are looking for. Also, easy to put on and remove. For $250 it is a good deal

Jonny

Hameed

I have heard one other person say something like that about the SAFC - apparently SAFC's don't work well on Lexus cars because the factory ecu would overide the settings after a short period of time...............

trbopooh

I think there might be some misinformation. Many RMM SC owners were running the safc with great success. I read somewhere (i forgot, but it might be my.is) about the ecu fighting the safc when the safc is trying to tune for high boost. I think the safc would work okay with NA and low boost applications. A safc works like a srt ecu. I don't see many owners complaining about the stock ecu fighting the srt.

trbopooh

Here's the info that I got from the my.is site. Even though the ecu's might be different, I think the info provides some good insight:

First step w/ tuning a car on a piggy back is going to be a scan tool, or something to monitor what the stock ECU is doing. If you are watching that, and makings sure the stock ECU is w/ in the parameters that it wants to be it won't mess w/ your tune. idle and and cruise are pretty much going to have to stay at that 14.7 range to keep the ECU happy. This is where your injector set up is going to be important, if you get to large you won't be able to get a stable idle at a Stoich air fuel, which will cause problems. The options are to use additional injectors (bad idea IMHO on a manifold not designed for it) or go to a true stand alone. (The other thing that will effect this is injector style, ie Disk, pintle, etc ..... http://www.turbosaturns.net/articles/injectors.htm seems to be a decent article on it, but i'll save that for another thread.)

As far as WOT, 12.0:1 is what i shoot for on a boosted car. This really shouldn't be a problem on a piggy back as long as the you have the closed loop tuning w/ in range before you start trying to tune the open loop areas.

Timing hasn't been dicussed here, but since this is about "tuning" and not just a/f, it really should be brought up. Depending on the piggy back you are using your a/f tuning can be effecting your timing. If the piggy back you are using is changing the air flow meter/map sensor signal of the car, the factory ECU will see more/less air and adjust timing to what it thinks is happening. As far as tuning timing, my method is to start off in a safe zone, if you are boosting an NA, pull a ° or 2 out per lb of boost to start off w/. Then advance it a ° at a time and whatch the HP output. Just make sure you have a proper load on the car on the dyno.

Dx3

iTrader: (13)

The problem is that we have no way to control timing on the 1uz - at least none I have ever heard of Which sucks!!

Jonny

Lexiss_sc430

iTrader: (2)

So I have a quick question.. I would understand why the newer vvt v8 engines would have a more intelligent computer but what about my 95 SC4....
Monday is my dyno day and I'm eager to get my safc2 on but would you guys think that after a while my computer will over ride the safc...
What do u guys think?



Over all with tuning I'm spending less than $300 for the safc 2 and dyno..

trbopooh

Yeah, I totally agree. I've been researching on a suitable ems system before I bought my kit and there seems no answer. I would think that if people that were having problems with the stock ecu fighting back, they would have jumped to a standalone like aem ems/hks f con/motec. A piggyback like the greddy emanage blue and ultimate won't work with our cars because they only work with 6 cylinder engines. Funny thing about them is that IS3's seem to have success with them, but I haven't even read one success story with the emanage on supraforums. Powertrain control solutions is supposedly coming out with something that will be able to control vvti. Then there's also the split second ftc. David (lextreme) is running that on his turbo ls4 (non vvti). It's supposedly able to retard timing. I don't even wanna go into megasquirt/autotronic/smt's.

trbopooh

I think you're gonna be okay. The vvti 1uzfe was only on the cars after 97/98. The people with the non vvti motors have it much more easy. There's many more choices available to them.

GS42NV

yea he eats glue!

lol ... im going with him on monday, it'll be interesting to see his hp gains. ill report back for whomever might be interested.

trbopooh

huh? care to clarify? your tuner eats glue?!!! does that help him tune better?

morris

iTrader: (2)

I have run supercharger and turbocharger with an SAFC2 and have had good results. I have gone all the way from 6psi to 17psi with the same SAFC2 and never had issues.

I alos have used 310, 370 and soon 440 injectors all with out any problems.

I dont see why you would have isues.