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· MKIV Fanatic
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Discussion Starter · #1 · (Edited)
Hello everyone,

This will be my second post :fro:

I have a BPU'ed MKIV supra right now, with the following mods:

1. HKS fmic
2. HKS SSQV Bov
3. HKS EVC3 BC
4. HKS Hyper Muffler
5. HKS 200pi intake
6. Over Boost? aluminum radiator *edited*
7. NGK spark plugs
8. TOM's ECU (piggybag, I believe)
9. Auto mission cooler

I've been reading posts and searching, but haven't found the exact answer to my question, which is... What is the next mod that I should do to make more power at the wheels, without spending too much money? I am looking for a cheap mod that won't cost me an arm and a leg, but rather something that will not require too much modifications.

Below are a list of some items, that are my initial guesses on items that will increase HP without spending too much $$$:

A. Injectors (if they do in fact help alot, what size should I get?)
B. Downpipe (does it matter which brand? how much HP increase?)
C. Cams (although they sound a little expensive)
D. Cam gears (I've heard they don't increase HP, but are mostly cosmetic)

Thanks much!
:eek4dance :run: :faint: :crazy:
 

· (Rare & Unique)
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A & D not needed. You should definitely get a DP if you dont have one already. Its your best bang for the buck for around 30-40hp
www.MKIV.com
 

· Registered
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my edit: probably no BCC needed as it is likely part of the Tom's ECU...

Otherwise, I agree the downpipe is the best bang for the buck.


You say you have an "HKS aluminum radiator"...is that right? I don't recall ever seeing or hearing about an HKS radiator.
 

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340 Posts
DP for sure. you will notice the difference, just dont forget to go to sears and get the 12" extension to get those nasty bolts when installing it.

and then...wash your car, the smooth paint helps you go faster. hahaha:crazy:

oh...and are you sure its an HKS radiator. not just a plain jane aluminum rad with an HKS stencil painted on it? if it is indeed a authentic HKS rad.... thatd be nice!
 

· MKIV Fanatic
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Discussion Starter · #9 ·
Downpipe it is!! As for the radiator, it was fitted by the original owner, which I *thought* was HKS, but it just says "Over Boost" at the top.

Any recommended downpipes for a BPU supra?
 

· got twins?
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Any "reputable" brand of downpipe will work (rod millen 'rmm' seems to be one of the most popular)...check one of the sponsors on this site for pricing.

Boost controller - turn the boost up for more power.

I think that is about it for "cheap" mods. Research converting your twins to true-twin mode...I did it, but many don't like that mod.

Have fun.
 

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Any "reputable" brand of downpipe will work (rod millen 'rmm' seems to be one of the most popular)...check one of the sponsors on this site for pricing.

Boost controller - turn the boost up for more power.

I think that is about it for "cheap" mods. Research converting your twins to true-twin mode...I did it, but many don't like that mod.

Have fun.
true twin is OK if you like the single turbo feel.

but you can get a better version if you physically remove the two butterflys out of the system like the "secret sauce" mod... it really gives an extra kick if your already maxing out the stock twins. huge difference for my car, and i wouldnt go back to sequential after feeling the difference anyway.
 

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true twin is OK if you like the single turbo feel.

but you can get a better version if you physically remove the two butterflys out of the system like the "secret sauce" mod... it really gives an extra kick if your already maxing out the stock twins. huge difference for my car, and i wouldnt go back to sequential after feeling the difference anyway.
Is there a link to this modification?
 

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its happened to some and not to others. but when you turn up the boost and the added flow of the downpipe, be sure to re-gap your plugs or put in new plugs with around a .032 gap as you will notice some hesistation..ish issues in the upper boost ranges with stock gapped plugs.
 

· MKIV Fanatic
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Discussion Starter · #16 ·
Any "reputable" brand of downpipe will work (rod millen 'rmm' seems to be one of the most popular)...check one of the sponsors on this site for pricing.

Boost controller - turn the boost up for more power.

I think that is about it for "cheap" mods. Research converting your twins to true-twin mode...I did it, but many don't like that mod.

Have fun.
Hmm.. Not sure if I can get those in Korea... lolz... we're very limited to stuff on ebay, or buy from Japanese sites after getting them translated :)

As for Boost controller, I have one, just forgot what it's called... LOL I currently run 13psi low boost mode and 17.4psi high boost (0.9bar and 1.2bar, respectively)



Do not buy the downpipe Suprastore offers that comes with the cat if you ever expect to pass emissions
I live in Korea, we have very easy, non legal ways to pass emission tests for around $100 more than the usual costs... and the certificate will be valid for two years :)

Get a DP and boost controller. Probably need a retune with each new mod.
I currently have a TOM's ECU, I know it's one of those pre-programmed ones, that require a specific build. If a downpipe isn't included in this build, would installing one still help increase HP?

true twin is OK if you like the single turbo feel.

but you can get a better version if you physically remove the two butterflys out of the system like the "secret sauce" mod... it really gives an extra kick if your already maxing out the stock twins. huge difference for my car, and i wouldnt go back to sequential after feeling the difference anyway.
I drive in a city where the traffic is just horrendous, I mean bumper to bumper traffic 90% of the times. The only times there isn't much traffic and I unleash the beast in my MKIV is when I go to the country side to visit my folks. In driving conditions such as those found here, how would TTC mode fare in terms of gas mileage/economy? Also, what kind of power gains could I expect? Is there really that much of a noticeable lag difference between sequential and TTC? If I wanted to "kill" porsche turbos and whatnot, would TTC be the way to do it? Also, is there a way I can "switch" between these different modes? I'm sorry I have so many questions, but you mentioined "secret sauce" and that just got me all excited.. lol :rockon:


Is there a link to this modification?
I've been searching SF all day, but wasn't able to find one. I think someone up top mentioned MKIV.com, I know they have a wealth of information there, might wanna check it out :D
 

· MKIV Fanatic
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Discussion Starter · #17 ·
I'm going to go ahead and revive this thread, can anyone tell me if changing the fuel pump to aftermarket ones that deliver more fuel will increase response and/or power? My car is currently a JDM BPU+ without the cams.
 

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I'm going to go ahead and revive this thread, can anyone tell me if changing the fuel pump to aftermarket ones that deliver more fuel will increase response and/or power? My car is currently a JDM BPU+ without the cams.
stock fuel pump is mighty powerful. more than enough for bpu and even plenty for aftermarket turbos on stock usdm injectors
 

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If your wires and the chassis is old / badly corroded, you might consider doing the battery and alternator wiring upgrade. I replaced my main power cables ( +/ -) with gauge 0 Stinger-brand audio wires and the difference in idling quality, responsiveness and transition from part-throttle open-loop mode to WOT / boost / closed-loop mode was immensely improved, I felt like I was driving a totally different car. Instructions on www.mkiv.com.

It's relatively cheap and not just your engine but all your electrical components will thank you for it.

After doing that mod, and fixing my programmable ECU (it had a minor short), we dyno'd my car again to be sure, retuned a bit and gained 25whp and 16lbs-ft of torque on the same boost levels (1.2 bar) and same ignition map but on an even hotter and more humid day. Previously my car dyno'd at 355whp and 365lbs-ft of torque, now I'm at 380whp, 381lbs-ft of torque. I have a JDM engine, turbos and cams but converted to USDM electricals with BPU++

I can't say for certain if the upgraded gauge 0 wires had anything to do with the power gains, I am merely stating the before and after results. But even before we dyno'd and before the ECU shorted out, the car was running better already.
 

· Super Moderator
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stock fuel pump is mighty powerful. more than enough for bpu and even plenty for aftermarket turbos on stock usdm injectors
The stock USDM TT pump is awesome - the stock JDM TT pump is much smaller, purportedly the same as the USDM NA pump.
So a factory US spec TT Denso pump would be a fantastic, 100% drop in easy upgrade for him at this point.

It wouldn't gain him much since he's still on the JDM injectors, but with an AFPR he could raise the fuel pressure to allow for more boost, since he's got a BCC built in to his Tom's remapped ECU.

CoconutGroveGuy, have you installed a downpipe yet? If you haven't, make sure to buy one that fits the JDM Supra, as the USDM twins have a different DP flange, so one suited for a US spec car will not simply bolt on to a JDM Supra.
Also, the JDM twins have slightly smaller wastegate ports which makes boost creep a problem once a 3in downpipe and full exhaust has been fitted. Many JDM Supra owners in Europe and Japan end up fitting a restrictor plate in the DP with a 45mm-55mm hole, which will allow most of the DP gains to be kept while still making enough restriction to prevent overboosting.

Beyond that, I would suggest an upgrade to USDM 550's with the matching restrictor pack, a suitable piggyback for fine-tuning such as the Apex'i SAFC, and a small single turbo such as a PT6262 that spools quickly enough to be enjoyed with a stock stall converter on the stock auto transmission.
Once you install a single turbo with an external wastegate, you can also eliminate the restrictor plate in the downpipe, as it will no longer be necessary.
 
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