Custom turbo kit questions.

[ziggy682]

Well, after debating between doing a CA18DET swap, an SR20DET swap, or turbocharging my KA24DE, I've finally decided to turbocharge my KA24DE.

I will be building a custom turbo kit, because it's something I've always wanted to do. I plan on keeping the boost down to about 7 pounds, and I'm not going for huge amounts of power. Here are my plans so far, and I have a few questions for the experts here.

T3 turbo from a Z31Rev Hard exhaust manifoldStarion intercoolerBlow off valve - undecidedWalbro fuel pumpFuel injectors from an SR20DET or 95-96 300ZX TTApex S-AFCVarious exhaust, intake, oil, and water lines custom made.

I have a few questions regarding fuel management.

Will using the 370cc injectors be enough to boost 7 pounds?

The S-AFC has different setting for high and low throttle, but can't read boost. Will the S-AFC work well enough with the air flow meter to reliably provide the right amount of fuel for boost, or will I have to get some kind of rising rate fuel pressure regulator as well?

A lot of turbo kits come with MSD boxes that cut back the timing as boost increases. Should I run something like this in my setup?

Well, that's all the questions I have for right now. Let me know what you guys think. Oh yeah, and just skip the "there's no such thing as cheap, reliable power" comments if your going to dog this low budget setup.

Thanks.

[george]

370's will be enough for 7psi, get a fuel pressure regulator from JWT, AFC sucks might as well go with the JWT crap, you dont need a MSD, dont forget a fuel pump, and finally there is no such thing as cheap reliable power. sorry had to say it cuz its true

[ITR_KILLR]

dont go cheap on your air/fuel delivery, or engine manag. or else you will be replacing an engine that will defeat the whole purpose of being "cheap" in the first place. My advise is to keep saving, and then do a bolt on KA kit, or a stock SR swap. You would be much happier with the results in the end.

just my .02 cents

[95_240sx]

If your stuck on getting a custom turbo kit, and want to piece it together, alone side the helpful advice of guys who know everything about 240's. Check out http://www.enjukuracing.com If you call them and you ask a question, they really know their stuff.

BTW, S-AFC's rock, I had one in my 240 and I loved it, even when its not modifying the air/fuel at all and you have the monitors on, it looks sweet inside your car.

Rick

[huguetpj]

congrats on your choice to go KAT!!!

the kit seems to be alright, don't forget the gauges

the 370cc injectors should be good to about 10PSI with stock fuel pressure (no fuel pressure regulator), but you might wanna up the boost past 7PSI slowly to be safe. And be sure to get the Walbro 255LPH HP pump, that's the best one and it sells for the same price as the standard 255LPH.

Since the S-AFC can be tuned by revs, and boost should be kinda linear with revs (until max boost) you can tune the S-AFC taking this into account. It's just a matter of trial and hopefully no errors. This is where a A/F gauge comes real handy.

Hope I was of help, you might also take a look at my site (see signature) and you'll find some other info I've accumulated along the way.

[ziggy682]

Since the S-AFC can be tuned by revs, and boost should be kinda linear with revs (until max boost) you can tune the S-AFC taking this into account. It's just a matter of trial and hopefully no errors. This is where a A/F gauge comes real handy.

Yeah, that's the one thing that bothers me about tuning the car. The S-AFC can only be tuned by rpm.

Does anybody know of a similar device that can can be tuned by boost without going to a stand alone engine management system?

Since the S-AFC can be tuned with different maps for low and high throttle, I should be able to tune the low throttle map for no boost, and the high throttle map for boost. I'm just worried that this won't be precise enough, so I would rather have a device that could read boost.

Yeah, I forgot to mention gauges, but I will definately be running an air/fuel meter, boost gauge, water temp, egt, and possibly oil pressure.

[ziggy682]

Another option I'm considering is the Greddy eManage. With the software and a MAP sensor, I could tune the system for boost, instead of just tuning for RPM. The only reason I'm looking for an alternative is because I don't own a laptop, which is required to tune the system.

[huguetpj]

haven't reserach much as far as AFCs go. But I do think there is one that sees boost, either by a pressure sender or a MAP sensor... but don't quote me on that

[SLIMMY240]

i dont know if i would go with rev hard exhaust manifold, ive heard alot about them cracking, and that you have to space them out some or just keep welding them. i think there was actually a post on it.

[revitoff10]

There are people that have gotten a S-AFC to work with a MAP sensor in place of the TPS. The unit can then be tuned by boost. I don't know specifics, but you better have the time, patience, and knowledge. Do a search on the miata forum, some people have gotten it to work, and the theory of how they did it should apply in most situations. I thought about this option on my car (turbo miata) but I'm not much into figuring out custom electrical things on the car. Plus there are plenty of good customized engine management options with the miata. Just thought I'd pass along the info in case it might help.

I'm seriously considering getting a 240sx as my second car and have been reading and learning for the past month. I also ran across a place that would be another option for a custom manifold for a turbo - I think the sight is http://www.etdracing.com/

Veronica

[ziggy682]

Wow! I just checked out that manifold at http://www.etdracing.com/. I think I just found the manifold I'm going to buy. For the money, that looks to be the best manifold I've seen for the 240SX.

[C-Kwik]

I can't tell you what the S-AFC does exactly, but any system that uses the MAF signal will recognize boost indirectly. All you need is the MAF signal and RPM and that will tell the computer how much fuel the engine needs. The MAF measures airflow. MAP sensors have to calculate airflow by sensing the pressure, temperature, and by knowing the Volumetric Efficiency of the motor. If tuned right, either will work fine. The Gredy Emanage is a piggy back system and as far as I know, if you have a MAF, you have to use one. You can upgrade though. But you also have the option of usinf a MAP sensor to calculate airflow to compensate when the MAF's limit is reached.

[gyfer]

I can't tell you what the S-AFC does exactly -> but any system that uses the MAF signal will recognize boost indirectly rant:nono

Air flow and air density is 2 different things.MAF = Mass Air FlowMAP = Manifold Absolute Pressure

MAF sensor CANNOT see boost. You run S-AFC to compensate extra boost you running, by fooling your ECU you have more air coming in ( determine by RPM , and your boost of course ) That's is why is hard to tune.

Tuning, more/less fuel in S-AFC, faster/slower rpm, faster/slower spooling, more/less air flow, wrong fuel ratio... againTuning, more/less fuel in S-AFC, faster/slower rpm, faster/slower spooling, more/less air flow, wrong fuel ratio... again.. and it keep going. To change your stock MAF to MAP is difficult too because you have to put temperature, huminity and Volumetric Efficiency into count. ( MAP don't do that )

There are cons and pros running MAF or MAP. I can't tell you which one to choose but I will stick with my stock MAF

Not sure if 370cc will "ok" for you 7psi setup. If I were you, I will get a FMU to raise fuel pressure while in boost. You never know you will need more fuel if you hit spike to 12psi.

In your turbo list, you forgot:WastegateBoost ControllerTurbo Timer (unless you can wait 2 minutes sitting inside your car after a hard driving, not very neccessary if you have money for new bigger turbo in next few years)Blow off valve ? hmm.. for MAF , you wanna try By-pass ValveStarion Intercooler ? woo... big and expensive. To run 7psi ?? I think is overwhelming.

Running KA-turbo is a wise choice.

[C-Kwik]

I can't tell you what the S-AFC does exactly -> but any system that uses the MAF signal will recognize boost indirectly rant:nono

Air flow and air density is 2 different things.MAF = Mass Air FlowMAP = Manifold Absolute Pressure

MAF sensor CANNOT see boost. You run S-AFC to compensate extra boost you running, by fooling your ECU you have more air coming in ( determine by RPM , and your boost of course ) That's is why is hard to tune.

Read my statement carefully. No, a MAF does not read pressure. I never said it does. I said it recognizes it. Meaning it will recognizes the additional airflow. Therefore you do not need a MAP sensor as long as the airflow is within the MAF's ability to measure. Though, I do think I was a bit unclear in saysing that "any system" as I was referring to a car's factory system, not the S-AFC (Like I said, I do not know much about it). MAF's will recognize the additional airflow from boost. But it does not mean it will compensate the fuel map correctly as Turbo motors are happier when running slightly richer.

[WDRacing]

MAFS work just fine for lower hp boosted applications. They just get restrictive for hp levels over 400. I have helped tune several cars with the SAFC and SAFR from HKS. I'd go with the HKS SAFR. Its a better system. Very easy to tune as well. I've seen some Skylines pick up a noticeable amount of performance before adding extra boost. I've also seen them trim down 720cc injectors on a CA18DET. The car still idled very well.

I like piggy backs because of the ability to change things on your motor without having to get a remap done to your ECU,

WD

[C-Kwik]

Depends on the type of MAF as well. Most hot wire types are not too bad as they have very little in the way of airflow. Door/Flap types and plunger types can be quite restrictive. I like MAF's just because of it's simplicity. At least the hot wire types anyways. It measures all the parameters to determine how much air the motor is ingesting.

[gyfer]

You sure MAF "measure" boosted air ?

Air flowing (velocity) at Atmospheric Pressure (0bar) is same as the air flowing at 30 psi. The different is density.

The idea is the same -> you have 2.4L displacement no matter your boosted at 10psi or 30psi. The different is the OXYGEN you get at higher psi because the air is Denser.

I don't have physic degree. I only get a B in my college physics.. so...

[gyfer]

oppps... hehe...this doesn't apply when you have MAF before turbo. My bad

[C-Kwik]

It doesn't matter if it is before or after the turbo. A hotwire MAF works by measuring the voltage needed to keep the wire at a certain temperature. It automatically accounts for density, humidity, and volume. Therefore, in theory, a blow-through MAF would work. But some have had problems with this set-up, likely due to turbulence issues.

[WDRacing]

I've tried both types of MAF, I had horrible idle problems with the blowthrough type. So I switched back to stock. Unfortunatly it was a fairly expensive learning curve, at 489 bucks.

WD

[BinaryVertigo]

it doesn't matter if the mafs is placed before, after, in between, on top, on bottom, doggy style, missionary, 69... whatever.

MASS air-flow sensor is just that, it measures the MASS of air that's being displaced for the amount that's being used by your motor, whether at zero psi or 69 psi, zero degrees or 69 degrees

the problem that WD was experiencing with the blow-through setup is NOT only related to blow-through but in some draw-through setups also. The cause: sharp bends right before the mafs which cause turbulance and uneven distribution of air-flow. This inturn causes the mafs to read the mass of air incorrectly.

-demitri

[C-Kwik]

Some have had bad experiences with draw-through set-ups due to the blow-off air being re-routed too close and/or too sharply(90 degrees). This caused turbulence which resulted in a poor reading. Even in NA motors, we've heard of poor MAF readings due to turbulence caused by aftermarket intakes. Notice that we have small velocity stacks in our stock filter boxes...

[gyfer]

MAF have different type. Some use "frequency" like musical instrument, higher the frequency, the faster the air flow ( aka Karmen Vortex Air Meter) . Some use "flap" device. Higher the air flow, bigger the flap open, more air flowing in ( aka VAF, Vane Air Flow meter) . In KA engine, we use "hot-wire". The cooler the wire, faster the air flow.

usually, Karmen Vortex type MAF have tubulence issue.

[gyfer]

It automatically accounts for density, humidity, and volumeHow MAF accounts density ?

MASS air-flow sensor is just that, it measures the MASS of air that's being displaced for the amount that's being used by your motor, whether at zero psi or 69 psi, zero degrees or 69 degreesHow MAF know if you have 69psi ?

[BinaryVertigo]

Quote »How [will] MAF accounts density?[/quote]Quote »How [will] MAF know if you have 69psi ?[/quote]P/V = nRT

MAFS does not account for densityMAFS does not know if you have 69psi

but look at the above equation,use simple logic and basic chemistry to see how our ecu DECIFER the info that is SENT by the mafs

[C-Kwik]

Denser mixtures have more molecules. The more molecules you have , the more heat can be carried away. The more heat that is carried away from the hot-wire, the more voltage is needed to keep the wire at the correct temperature. This will tell the ECU that the motor is getting more air.

Again, the MAF does not read pressure. But it will read the airflow required to produce X psi of air in a draw-through configuration, or in the case of a blow-through MAF, it will read the effects of the higher pressure in addition to the airflow. That's why I said it will read it indirectly. If this weren't possible, it would be quite difficult for JWT to develop a ECU program for our KA's without adding a pressure sensor, or knowing how much boost you will run. They use the same mapping for 6 psi as they do for 10 psi. The MAF reading tells the ECU how much air and indirectly, how much boost, and provides the correct timing and fuel maps for it.

[BinaryVertigo]

c-kwik, where are you at in SoCal?i'm in huntington beach

-demitri

[cnichols]

There are people that have gotten a S-AFC to work with a MAP sensor in place of the TPS. The unit can then be tuned by boost. I don't know specifics, but you better have the time, patience, and knowledge. Do a search on the miata forum, some people have gotten it to work, and the theory of how they did it should apply in most situations. I thought about this option on my car (turbo miata) but I'm not much into figuring out custom electrical things on the car. Plus there are plenty of good customized engine management options with the miata. Just thought I'd pass along the info in case it might help.

I'm seriously considering getting a 240sx as my second car and have been reading and learning for the past month. I also ran across a place that would be another option for a custom manifold for a turbo - I think the sight is http://www.etdracing.com/

Veronica

I contacted etd racing about their manifold because it does look as if they do quality work...but they haven't finished development. Looks like it will be until Spring sometime before it's finished.

[matt0941]

I'm sorry I am still fairly new to the whole MAFS MAPS deal, but why would NA cars need an MAF?

[C-Kwik]

c-kwik, where are you at in SoCal?i'm in huntington beach

-demitri

I'm in Stanton. North of you up Beach Blvd maybe 5 or so miles...I work in Fountain Valley.

You gonna go to the cartune meet on Saturday?