boosting a friend's KA

[BoostedBoogie]

hey guys. my first post. well anyways, my friend came to me because he wants to turbo his newly-acquired 92' 240sx. everything on it is stock. im installing in some coilovers for him next week, front/rear strut bars, and some audio stuff. this isn't going to be his daily driver.. or so he tells me. we have $1000 to spend right now, and he earns another $150 per week.

i don't own a 240sx myself, but own a boosted car.. which is why i came to ask for your guys help. this setup i have thought of which applies to his application. he owns the DOHC KA24 and plans to run no more than 7psi, 4-5psi during break-in period.

T25 turbo (small/quick spool for drifting/abusive driving.. no freeway driving with this car)
turbo manifold (cheapest place to buy one?)
IC piping (2" Hotside piping with heat wrap/2.25" Coldside piping)
Starion FMIC (good enough for the 5-7 psi he wants)
330cc Injectors (correct me if im wrong, but will stock injectors be good enough?)
Vortech 12:1 FMU
upgraded fuel pump
JWT ECU (again, stock ecu be good enough?)
BOV (maybe the hks SS or the TurboXS RFL.)
ACT Clutch (what is your best recommendation?)
manual boost controller
gauges (a/f, exhaust temp., boost, etc.)
triple pillar pod
oil/water fittings
flanges
oil/coolant lines
apex'i s-afc for piggyback tuning

some things you guys should know that we will try:
- we plan to run a 2.5" dumptube from the downpipe to the side of the front bumper for our exhaust (again this isn't going to be a daily driver)
- we don't plan to go over 7psi.. so hopefully we can avoid internals and most aftermarket fuel parts.

i MAY be a n00b to the board, but im not a n00b to the lifestyle. any help is appreciated.

[BoostedBoogie]

and one more question... i think i noticed that your cars have a MAF (think located next to airbox).. is this true? if so, i would have to place this MAF in between the turbo compressor housing and the air intake filter, correct?

[Jeff240sx]

Guy.
All I can really say is search. If you want to see what other people do, check out:
www.240sxturbostyle.com (my website... updating, so it's kinda ugly right now)
www.boosteds14.tripod.com
and
AceInHole's website. I don't know it offhand, but check his profile for it.

A t25 is too small for a 240sx.
JGS has the cheapest manifold, but it's a weld-it-yourself.
330cc injectors aren't readily available. 370cc are. 95-96 300zx, and on Ebay under sr20det injectors.
Nix the Vortec FMU, because the JWT ecu will supply the fuel, and no, the stock ecu won't control the injectors, and you'll run like hell.
ACT clutch. Stage 2 for your power requirements.
You won't need a boost controller if 6-7psi is your goal, because most turbos from stock cars are right around there, preset with the internal actuator.
We don't get triple pillar pods, so don't search for one too hard. You can get a dual and a single though.
AFC is once again useless. JWT will tune the ecu very rich already.
2.5" downpipe to the front bumper? Huh? The heat will be so tremendous there, it will melt things, sound like ass, and look retarded. Just mate up the downpipe to the exhaust.
-Jeff

[BoostedBoogie]

yes i have a jgstools manifold on my setup as well.. its basically the only place that can provide a manifold for my b6e motor.. besides a custom one.

if the jwt ecu will take care of the richness, is your maf adjustable with a/f? i know mine is and i would like to know if it is so we can lean up the mixture if its TOO rich.

are the sr20det injectors a bolt-on to the ka24de? im guessing yes.

the t25 is the turbo application we're looking for. we don't want mid-top end power.. we need instant power with no lag for a few events we plan to attend.

thanks for the reply and the assistance. anyone else?

[turbo240sx]

your friend is going to need more than 1000 bucks, the JWT ecu alone is 500 bucks and change. good luck with it but a t25 is way too small, a t3/t4 would be better. and our MAF isnt adjustable, the stock maf cant read too much boost that why alot of us that have KA-T's have the cobra maf. and the BOV has to be run closed loop unless you run the maf blowthru style or have a apex-i AFC.

[BoostedBoogie]

damn thats what i was afraid of.. are the mafs at least capable of 5 or 6 psi?

and if not, where can i find those cobra mafs besides junkyards? any specific year of the cobra?

and again, we are leaning towards the T25 because we need a turbocharger that has almost NO lag and can give us 'power-on-demand'.

thanks for your help.

[Jeff240sx]

Originally posted by BoostedBoogie
damn thats what i was afraid of.. are the mafs at least capable of 5 or 6 psi?

and if not, where can i find those cobra mafs besides junkyards? any specific year of the cobra?

Yea. The stock maf can handle like 12psi according to JWT.
The Cobra MAF has to be a 1993, with one of two part numbers. JWT only makes computers that run the Cobra MAF that control 50# injectors, which in your case, it entirely too much. Don't do it.
Get a 14b or a t3 turbo. The t25 is too small (for the third time). You can adjust the t3 (get them off Fords (probes, t-birds, stangs) and the z31) with different housings ($200) for spool up time.. and it'll actually make power instead of heat.
-Jeff

[SRKperformance]

also a stock starion ic in good condition will be able to reliably support and cool effeciently up to 17-18 psi of boost. I have a customized starion on my sr car. I used to have a stock one but i recnetly had new custom tanks put on it and retested and checked the core. My starion will support about 21 psi of boost. Just make sure you have it tested, many have been abused or messed up. Also it is true that for a 2.4l displacement motor a t25 is goin to be far too small, and finding or making a custom manifold to fit the t25 exaust flange is going to be a real bitch of a time. I would get a small t3/t4 with a moderate exaust ar like .60 or so and a front ar of around.63 or so it will spool up at around 3500 rpms and make alot of power with only 7 psi compared to a t25. No need for bb. Also if you ever want it you can boost up to 18 psi or more with a good t3/t4. Id go with some sr20det stock 370cc injectors and a jwt ecu retune if your not used to playin with an afc or standalone. Combine that with a custom downpipe and exaust with the wastegate external routed back into the dp and youll have a good setup. I would go with a inexpensive external gate like a racegate or delta gate from turbonetics if your trying to save money, you can prollly find a used one on ebay. Also youll need to decide on a way of plumbing your starion ic, the stock starion has a pipe that crosses over the top of the ic and another inlet on the same side. You can route the piping so it goes in and out on the same side but youll have to cut a hole in your car where the stock charcoal canaster is located or you can cut the stock starion piping off completely and route the piping down in a traditional style on in one side out the other, but youll need to get a mini battery and cut a hole where your stock battery tray is located. not a big deal just bust out the sawzaw!

[sykikchimp]

The stock injectors will work with the Vortech FMU, but having an AFC around to help get the A/F right would be nice there.. you'll need a Walbro fuel pump to help flow the extra fuel pressure. With the FMU the injectors will do about 7psi before leaning out.

(not necessary at the 5-7psi level) - the 300zx/sr20det 370cc injectors are plug and play. You could adjust for them with the AFC if you like to support a bit more boost.

that is by far the cheapest route.

I know of a couple guys running blow through setups with the MAF in the cold pipe, and BOV on the hot pipe with minimal problems (none that I know of), but if you run the MAF the traditional way (like turbo240sx was saying) closed loop is a safe bet to keep the idle from sucking. BUT.. if you've got the AFC.. you could try to vent atmospherically.

The JWT route isn't cheap..

$600 for the ECU, plus $250 for injectors, plus walbro 125.. Almost $1000 just for fuel management. DEFINATELY the safe way to do it. But not the cheapest.


I agree with the other guys here that a t25 is MUCH too small. a T28 Would maybe work for you app. I would highly suggest a T3 or T25/3 hybrid of some sort. The KA likes larger turbos.

[Jeff240sx]

Originally posted by sykikchimp
(not necessary at the 5-7psi level) - the 300zx/sr20det 370cc injectors are plug and play. You could adjust for them with the AFC if you like to support a bit more boost.

that is by far the cheapest route.

The JWT route isn't cheap..

$600 for the ECU, plus $250 for injectors, plus walbro 125.. Almost $1000 just for fuel management. DEFINATELY the safe way to do it. But not the cheapest.

I have to disagree.

AFC Setup:
AFC - $330 shipped
Pump - $120 shipped
Injectors - $160 shipped (sr20det injectors from ebay)
Dyno Tuning - $100/hour for AT LEAST 1.5 hours. If not, you'll get heat sink in the tuning, and not run right when the car is cold.
Total: $760

JWT setup:
JWT ecu - $590 shipped (-$100 for sending in ECUs)
Pump - $120 shipped
Injectors - $160 shipped]
Total: $770, and no dyno time needed.
-Jeff

[AceInHole]

I got you both beat:

Hacked MAF: $50 (assuming S14 MAFs work on S13's)
370cc injectors: $100

Total cost: $150

Of course, you need some balls to risk your engine to that setup.....

[BoostedBoogie]

our realistic goal is to bolt on around 30-40 WHP.. we're not trying to go for a crazy 300 or 400 whp car.

does the T3/T4 hybrid give low end power around 3000 and fully boost up to 6000? how about the T28 aka t25/t3 hybrid?

[Jeff240sx]

Originally posted by BoostedBoogie
our realistic goal is to bolt on around 30-40 WHP.. we're not trying to go for a crazy 300 or 400 whp car.

does the T3/T4 hybrid give low end power around 3000 and fully boost up to 6000? how about the T28 aka t25/t3 hybrid?

Ok. You need a T3 turbo, manifold, BOV, and a 8:1 rrfpr with a fuel pump. Boost to about 6 psi, and you should be about 200rwhp. Get an intercooler, and you may look at 215-220rwhp. That's all you need.
-Jeff

[240Stilo]

Originally posted by AceInHole
I got you both beat:

Hacked MAF: $50 (assuming S14 MAFs work on S13's)
370cc injectors: $100

Total cost: $150

Of course, you need some balls to risk your engine to that setup.....

Hacked MAF: $50
370cc injectors: $100
The balls to risk your engine: Priceless

[240Stilo]

Originally posted by Jeff240sx
Ok. You need a T3 turbo, manifold, BOV, and a 8:1 rrfpr with a fuel pump. Boost to about 6 psi, and you should be about 200rwhp

How about upgraded injectors? Would he be pushing the OEM ones pretty hard?

Originally posted by AceInHole
I got you both beat:

Hacked MAF: $50 (assuming S14 MAFs work on S13's)
370cc injectors: $100

Total cost: $150

Of course, you need some balls to risk your engine to that setup.....

Hacked MAF: $50
370cc injectors: $100
The balls to risk your engine: Priceless

[sykikchimp]

Originally posted by Jeff240sx
I have to disagree.

AFC Setup:
AFC - $330 shipped
Pump - $120 shipped
Injectors - $160 shipped (sr20det injectors from ebay)
Dyno Tuning - $100/hour for AT LEAST 1.5 hours. If not, you'll get heat sink in the tuning, and not run right when the car is cold.
Total: $760

JWT setup:
JWT ecu - $590 shipped (-$100 for sending in ECUs)
Pump - $120 shipped
Injectors - $160 shipped]
Total: $770, and no dyno time needed.
-Jeff

subtract the AFC, and injectors like I was saying cause they aren't necessary for his setup =
FMU =140
fuel pump = 120
=260..

the AFC and injectors where "nice to haves"

The setup you posted just a bit above this would be perfect for this guy..

[Jeff240sx]

Originally posted by 240Stilo
How about upgraded injectors? Would he be pushing the OEM ones pretty hard?

Sure he would. But it's also been people's sole fuel management at 10psi and still worked fine. They're great for 7psi, hell, even $4000 turbo kits give you a 8:1 FMU.

Originally posted by sykikchimp
The setup you posted just a bit above this would be perfect for this guy..

Heh.. I know.
-Jeff

[240Stilo]

Would colder spark plugs help out his setup or will it just be under the "nice to have" section?

[turbo240sx]

Get a 14b or a t3 turbo. The t25 is too small (for the third time). You can adjust the t3 (get them off Fords (probes, t-birds, stangs) and the z31) with different housings ($200) for spool up time.. and it'll actually make power instead of heat.

i think your mistaken jeff. the ford probes used IHI turbo rhb5's,
and so did the t birds in cetain years. and JWT does do an ecu for 72 lb msd's, not just 50 lb. and if he wants to use a t25 let him. we all told him its too small but if he want to use let him use it. its his setup.

[Jeff240sx]

Originally posted by turbo240sx
i think your mistaken jeff. the ford probes used IHI turbo rhb5's,
and so did the t birds in cetain years. and JWT does do an ecu for 72 lb msd's, not just 50 lb. and if he wants to use a t25 let him. we all told him its too small but if he want to use let him use it. its his setup.

You've got a probe, so I won't argue there. Why did I think that? Is the rhb5 similar in size to a T3?
Yea, JWT does 370cc, 50# and 72#. The latter two are coupled with the Cobra MAF, I'm pretty sure.
-Jeff

[turbo240sx]

its the same size as a t25. the t birds had IHI's i believe in 87 and 88, and some had T3's. but those that had IHI's had a bigger compressor housing than my probe. same center section and exhaust side but bigger comp housing .. and it can push alot more boost than a t25 and not blow up. mine is a perfect example. IHI's are good turbo's but hard to come by.

[Jeff240sx]

Originally posted by 240Stilo
Would colder spark plugs help out his setup or will it just be under the "nice to have" section?

**** **** Rule Of Thumb **** ****

1 step colder for every 100hp you add, or if you get an ignition system, 1 step colder when you boost the motor.

-Jeff

[RicerRacer]

dude, wat the heck yu guys thinking. non daily driven. t25, no built internals. u dont plan on goin over 7+ psi. yall got about $1000 bucks to spend. wats the point??? yu guys planning on making a low budget, backyard production race car or wat.

[240Stilo]

Umm....yeah.

EDIT:

Originally posted by Jeff240sx
Yea. The stock maf can handle like 12psi according to JWT.

12psi from what turbo?

[BoostedBoogie]

Originally posted by RicerRacer
dude, wat the heck yu guys thinking. non daily driven. t25, no built internals. u dont plan on goin over 7+ psi. yall got about $1000 bucks to spend. wats the point??? yu guys planning on making a low budget, backyard production race car or wat.

yes now you're getting it. basically that's our goal, for now.

after a few events and abuse, we will start upgrading ignition, more fuel, more tuning, maybe standalone?, internals, drivetrain, and an upgraded turbo that is a direct replacement/bolt-on for the T25. then, my friend, THAT is when a point comes into mind. *meaning turboing this car for a few events, then doing some REAL tuning to the car*

[Jeff240sx]

Originally posted by 240Stilo
Umm....yeah.

EDIT:

12psi from what turbo?

Ok. PSI is a bad term to use here. Many people have run their stock (unadulterated, Ace!) MAF to 250rwhp.
-Jeff

[240Stilo]

Do you have a link or something that can tell me how to calculate how much cfm has to travel through the maf to get 250rwhp? 250 is probably the most I would want out of my car anyways and I've been trying to work out numbers to see how i can try and run Ace's hacked maf setup.

[Jeff240sx]

Originally posted by 240Stilo
Do you have a link or something that can tell me how to calculate how much cfm has to travel through the maf to get 250rwhp? 250 is probably the most I would want out of my car anyways and I've been trying to work out numbers to see how i can try and run Ace's hacked maf setup.

Ace's hacked maf allows more air through to run 370cc injectors.
Anyway, if you look in the FAQ section for a thread called Turbo Sizing and Help (or something like that), there are numerous links to help you figure out the CFM for 250rwhp. But.. on a CT-26 turbo, it was about 10psi.
-Jeff

[240Stilo]

Well I'm not 100% sure but take a look at this....

With the stock injectors being 270cc and upgrading to 370 cc, you would need to make a 37% increase of area in the maf. 37% of 270 makes about 100 which is the amount of cc's added. I measured the stock maf to have diameter of 3 inches. This gave me an area of 7.065 inches squred. 7.065 inches squared is 63% of the area we wish to obtain. So the area we want is now 11.214 inches squared. I then found the diameter of this ideal area to be 3.75 inches.

So in conclusion 370 injectors with a 3.75 diameter hacked maf will balance out the pulsewidths correct? How does this setup idle? Sounds like it would work fine at WOT.

One more thing, I can't find a compressor map on the ct-26 to figure out how much cfm flows at 10psi. I'm guessing because it was a stock turbo.

[BoostedBoogie]

ok update:

we had a custom manifold made.. log style.. and had a T3 flange welded to it. after half an hour, the stock header was removed and with the turbo and manifold on, there's TOO much stuff in the damn way. how the hell do you guys make room to fit a turbo on the ka24 (this is the dohc).. there's like wiring everywhere. any help here i dont want to have to make another manifold.

oh another question, would it be stupid for me to use a stock T3 on the rather medium size and hybrid it to make a T3/60-1?