Going Single w/ Stock Fuel/ECU Vs. Going BPU. Thoughts?

[Guest Boostednavyac]

Hello all, wanted some opinions about my potential upgrade path choices for the future. First some background info...

I have a '93 JDM Supra RZ 6 Speed. It is completely stock, except for a catback exhaust and FMIC. She has 107k on her.

I've been debating what power output I want from her eventually- but I want her to be more of a weekend/fun car once I move back to the US (currently living in Japan). I'm thinking I will want around 600ish RWHP and to be a street car with occasional drag passes.

 

So I have been thinking- would it be a more economical/easier path to just put on a single kit and keep my stock fuel/ECU setup for now? Since it is J-spec, I am limited by having the 440cc injectors, Ceramic turbos and the fuel cut/speed limiter. If I want to go BPU, I'd have to get a BCD, some sort of downpipe with a restrcitor plate, a boost controller, and I'd have to worry about those ceramic turbos. And I'd most likely be sub 400WHP, and would have no need for the BCD/Stock twins downpipe once I eventually go single.

 

If i just got the single turbo kit I wanted in the first place, couldn't I in theory just run her at low boost levels? (I.E. 0.9 Bar)

That would negate the need for the BCD (if I understand correctly, it's only based on what pressure it reads, if it's Airflow based please correct me), I could make better than stock power, keep it on the stock fuel system, clutch, and ECU, and then later when I want to upgrade to a standalone or MAP ecu, I could throw in bigger fuel pump/injectors, get a stronger clutch, tune her and still have the power I wanted. This would in theory prevent me from wasting $ and effort on BPU parts that wouldn't carry over to the single build.

 

I'm new to the Supra world but I try to read the forums as much as I can. If I missed anything please enlighten me!

Thanks in Advance

Edited November 6, 2015 by Boostednavyac (see edit history)

[Tricky-Ricky]

The single turbo could be done, however you would likely be only running something like 2psi on a turbo that's capable of making 600BHP at the flywheel, as despite being MAP based it still measures mass airflow by pressure, so with the extra airflow you will need to run very low boost, you could run a piggyback and decent adjustable FPR turned up a little to squeeze some more flow from the injectors, but as they will be 15 years old I am not sure how reliable they would be when pushed, so I would either go BPU or proper single install.

[Swampy442]

Theres many schools of though on this, and only one correct one. Guys in the US run big turbos on stock setup all the time, its not that common in the UK/Europe.

 

The 'right' way is to get good quality management, fuelling and mapping to make the most of it, and you will see big gains over the stock ECU etc.

[Guest Boostednavyac]

Thanks for the input Tricky-Ricky. I was hoping a mid sized turbo at around 10psi/.8 bar would be in the low 400bhp range but perhaps I am incorrect and that would be too much for the stock injectors.

[Guest Boostednavyac]

Swampy442- in your opinion then- what suffices as good quality management? Seems the proper standalones are like $2000 USD. I used to use DSMLink in my Eclipse turbo back in the day- but that was only $700. Would you consider the MAP ECU sufficient? Unfortunately this car is my daily here in Japan, so reliability is at a premium and I haven't found any shops here that can speak English, lol.

[pedrosixfour]

Speak to one of the active club members who work at Titan Motorsports about an AEM ECU mate.

 

I was onto them recently and was offered a very good deal on the above PLUS a nearly new dash display unit they had advertised on the forum.

 

My circumstances have changed however and I no longer require either. But don't cry for me, I'm sorted in ways I never thought possible!

 

 

Edit: It was 2jzmk3 I was speaking to on the subject.

Edited November 6, 2015 by pedrosixfour (see edit history)

[Swampy442]

Swampy442- in your opinion then- what suffices as good quality management? Seems the proper standalones are like $2000 USD. I used to use DSMLink in my Eclipse turbo back in the day- but that was only $700. Would you consider the MAP ECU sufficient? Unfortunately this car is my daily here in Japan, so reliability is at a premium and I haven't found any shops here that can speak English, lol.

 

Decent management is decent money Im afraid. 2 grand isnt that strong really. Its down to what you can afford really. But you can get 400hp (400whp is nearer 500 crank hp) out of an entirely stock engine with BPU mods and an ECU, going single will cost thousands, way more than you think it will. Besides you're in Japan, theres no better store of knowledge than the place that made them! Find a big tuning house and speak to them.

 

Another question is why do you want to go single in the first place?

[Guest Boostednavyac]

Thanks Pedrosixfour- I will look into it.

Swampy- I was looking to go Single with the future in mind. I want to eventually go bigger power, probably 600ish WHP, once I Move back to the US and she's not my daily driver anymore.

I was thinking I would try and avoid buying stuff twice by going single right away and skipping BPU only mods (restrictor plate, BCD, Downpipe) and I was trying to retain the stock ecu and fuel system. In my past experiences once you start messing with fuel and electronics that's when reliability becomes less certain, and she is my daily here since I'm only allowed one car.

Going BPU is certainly cheaper and easier I was just trying to avoid redundancy down the road for my eventual goals.

[j_jza80]

As has been alluded to, you first need to find yourself a mapper, then find out what systems they will use

I'd say as a minimum you want a piggyback like a Greddy emanage. Many tuners in Japan with use the HKS Fcon line, which are pretty good, and available for sensible money used.

[Guest Boostednavyac]

Thanks for the suggestion J_Jza80, problem is I need to find one that speaks English

It's been more challenging than you would think, lol.

Since we are on the topic, anybody know of any Supra guys in the Kanagawa prefecture? Haha

[ashloys]

I know a couple of people who live in Japan, from the UK and could probably help sort you out or translate lol

[Scott]

You could probably get away with SOME boost, the stock fuel system massively over-fuels the stock tubbys so you would have some headroom for more airflow. I know of at least one single turbo that was on the stock fuel system and running around 400-450hp. There's no way it was anywhere near ideal though and you are taking a risk.