tuning questions..

[Awyman18]

ok so im nearly at my stopping point of mods on my 1990 supra. Im hitting 11psi exhaust fmic etc etc. Wat is the best way to tune ur car? ive heard mega squirt, AEM, but wats this about using an AFC NEO and FPR? how exactly does that system work when u incorporate lexus afm and 550cc's?? also, i still plan on using my ct26, but i dont really plan on going higher than 14-15psi of boost. i dont want to go all crazy with my supra, but i want it to be pretty solid. Any help would be fantastic

[cre]

I recall writing a more thorough explanation concerning the differences between stand alone EMS and piggy backs and the different features of some of the more common ones, but I'm not having luck locating them. Here are threads with some of my old posts on this matter. The easiest way to find more is probably to search "tuning" or "MAFT"... specifying posts by me using the advanced search may help further.

http://www.toyota-supra.info/forums/...etter-now.html
http://www.toyota-supra.info/forums/...ore-power.html

About the MAFT Pro specifically:
http://www.toyota-supra.info/forums/74631-post6.html

[Awyman18]

ok question again cre lol if i go the maf-t route, the gm maf as in this guy http://www.fullthrottlespeed.com/ite...=050SUPRA3MAFT
do i really need the lexus afm? im confused...lol and a friend of mine is saying i can keep using my 440cc injectors instead of upgrading to 550cc?

[cre]

I know their products well; The developer is a very nice guy and very helpful.

The basic MAFT is not a very tunable device. I don't know how much adjustment the potentiometers inside allow for. I can think of a couple tricks to squeeze a little more out of the stock injectors with it but it's not significant and not what the decive is built for. The ECU is calibrated for the amount of fuel that the stock injectors flow per a given unit of air. No matter how you tweak the system you will always be limited by the ECU's maximum allowable duty cycle for the injectors. So, either you need more fuel per cycle from the injectors so that when tuned for an ideal mixture the ECU will actually believe that less air is coming in than is the case or you use a FCD to lie to the ECU along with a fuel controller to tune the injectors closer to the edge of the ECU's fuel map per RPM.

There's no cheap cheat that's widely recommended... FCD's are old tech and very unpopular with the Supra crowd (for good reason), adjustable fuel pressure regulators are recommended for tuning purposes but seldom for an adjustment of +/-10% (especially not on old injectors).

Your friend's not thinking it through or thinks you've got some additional means of controlling your fueling. Physics and math: 25% more air needs 25% more fuel.... That right there negates the possibility of running the Lex AFM with the stock injectors. The popularity of the Lex AFM is it's simplicity (please people, stop trying to complicate it ): Add Lex AFM, swap injectors and GO DRIVE!!! No electronics, no tuning, no time on a dyno needed, you keep the protection of fuel cut but it's bumped up 25% along with the air and fuel.

The MAFT Gen II is a probably a better option which is thoroughly adjustable. Much of its functionality mirrors that of the MAFT Pro but it lacks the boost control and AFM/MAF deletion capabilities. It does support GM MAF conversions though. This does have fuel control capabilities and timing control. I believe it's also capable of capping the Ks freq output such as an FCD does.

[Awyman18]

awww gotcha makes sense now lol. after 550cc and lex afm how much can i turn the boost up do u think? and think going a safc is reasonable or kinda meh?

[cre]

I think most people end up around 15psi on a stock CT-26.

A better intercooler with lower pressure drop will make a big difference too. Not only does it cool better, but the turbo isn't pumping 18psi of hot air (out of it's efficiency range) to just get 14psi to the intake manifold due to a 4psi restriction at the stock IC. Even if the IC doesn't have better thermal characteristics you will end up with a cooler charge as the turbo isn't working so hard.

You should always get a baseline dyno performed whenever you install a significant mod like this. Just a baseline: A single pass on the dyno with the boost set to the desired level. Make sure the car is warm. Shouldn't cost more than $20... no tuning or multiple runs are usually needed. You're not looking for the best power, you're looking for danger signs in the AFR readings. If the shop isn't able to print out the AFR graph on the HP and TQ graph you need to find someone who can. I haven't ever had a shop tell me they couldn't, if you do find one it's probably amateur hour. They should also be able to tell you your AFR at idle while the car's on the rack.


Now let's get back to complicating things:

Here's where I am on the fence about the Lex AFM upgrade... Many people have said that some tweaking of the air bypass screw (sometimes requiring a longer screw) is needed to get the engine to run well at idle and low-mid load when in Open Loop. This requires a wide-band sensor to monitor AFR while making adjustments. Also, as there's always more performance to be had from a nice clean tune a fuel controller can open things up quite a bit even with the Lex... So, why bother with the Lex AFM? Perhaps just go with the 550s, stock AFM and a fuel controller? The stock AFM is a bit more of a bottleneck, but you'll never move enough air through the CT-26 to see it. With a fuel controller you don't need the Lex AFM, you just need more fuel per cycle. So, in exchange for a little more of an initial investment you gain more flexibility and a bit more performance... Older model fuel controllers are very affordable these days.

So you like the idea of a more tunable system but still want the reduced bottleneck? Well, you can run the Lex AFM and a fuel controller, but it may be worth considering a system such as the MAFT Gen II which will allow you to run a GM MAF (the 3.5" is HUGE) and has a built in fuel controller. It's also capable of spark advance control, datalogging and can be integrated with a wideband controller giving you a nice mobile tuning platform (laptop not included ).


I'm assuming you have little or no experience with tuning though and the setups I've discussed grow steadily in their learning curve and complexity. I'm just trying to set out the common choices and the ins and outs of each in a brief fashion. The Lex is still the easiest and cheapest if you find you don't need additional tuning to get it running smoothly with your setup. If this is your daily driver I'd stick with the Lex for now, you can always sell it off later if you decide to move on to another system and you'll still want the 550s.

[Awyman18]

yea as u said i have no tuning experience and my supra is my daily driver so im going to take ur word for it and go lex afm/550cc. So i can safely do the lexus/550cc upgrade with out any sort of fuel management right? Simply because +25% air +25% fuel = happy engine? I think id rather just go stock afm, 550cc and fuel regulator. Im not trying to be crazy with it, it is my daily driver after all lol But a solid 14-15psi of boost seems nice. But as in fuel regulartor, does a safc count or is this a totally different system?

[cre]

Yes, the SAFC, SAFC II and NEO are three of the most common fuel controllers. If you have one already you don't really need the Lex AFM unless you've already got one handy. As I mentioned, some people found some tweaking was needed to get the car running smoothly but this can be accomplished by manipulating the physical hardware if you don't have a fuel controller. Also, as previously stated, a baseline dyno will let you know if you're running too rich or lean at WOT and they should be more than happy to tell you what your car is idling at.

[Awyman18]

yea one of my friends has 2 lex afm's so i can probably buy one of his or something but thanks cre. Ur lots of help lol