hi looking at 05 jdm STi
atm she has pretty bog standard apart from a ss pipe from the cat
and a dump valve... nothing more

looking for a healthy 350hp + and torque to match ...;-).

whts the best route ????

 

Cosworth/K&N panel Filter
3 port boost solenoid
3" bellmouth decat/high flow twin scroll downpipe
3" mid section/backbox
Remap to approx 340 to 360 bhp

Could do with uprated actuator maybe
NGK 7 plugs (edited to clarify: this is more a precautionary measure to make sure you don't waste time & money, trying to map with old plugs. Rubbish spark can cause ECU to retard ignition while mapping.)
Probably clutch soon after

 

I got 340bhp with cat back, panel filter, 3 port solenoid and a dynamix remap, so with a downpipe you should be where you want to be, I also fitted a fuel pump to be on the safe side. You don't need a 3 inch exhaust for 350bhp tbh, but if you do fit one will be ready in case you go further in the future.

 

Spark plugs, filter are a must at least before a remap. The fuel pump is highly recommended in my opinion along with a 3 port solenoid, although that is not essential.

Decat/sports cat will net the biggest gain in spool and power delivery.

Good results daz.

Graham

 

JDM's already run NGK 7's if its been serviced properly (factory fitted), fuel pump... debatable on a JDM, they run around 310-320bhp out of the box, its not going to be running 90% efficiency on the standard pump on a factory car tbh, though the 3 port boost solenoid is worth doing

Tony

 

Ive got a standard jdm sti apart from a 3" Milltek with sports cat, panel filter and remap. 350bhp, 375lbs torque. Driveability and power band is phenominal.

 

I just sold one, 340BHP. Had TSL exhaust, panel filter and was mapped, nothing more.

 

This is not only about the parts that some people have commented on.... the key "thing" that will make a BIG difference in the driveability (it is not all about peak figures!) is utilising ECUTEK's MEGAROM capabilities. This is additional functionality within the ECU that is available via ECUTEK software, and an appropriate mapper that knows how to exploit it.

I would rather spend my money on that than some of the other things mentioned on this thread.

The biggest power increase will come from the remap and a 3" decat. The other things are nice to have and you certainly don't need a fuel pump on the JDM at this level.... although if it was me I would change it as a a precautionary measure. These standard JDM pumps seem to run far better than the UK (it's the same flaming part number). I was running this pump up to 500bhp without any issues (and I'm not the only one).

Not sure why you would want to change the plugs unless they are knackered.

 

yes will buy air filter /
prob fuel pump
and trip to mapper

worth investing in a down pipe .....

wht exhaust systems r there nothin more than 3"
...?

 

I dont think your going to go far wrong with this system, im after one myself
http://www.tracktive.co.uk/product.php?id=100091

Tony

 

As much of the above. Optimise air intake, full exhaust including decat, three port solenoid and remap. Running a safe 1.55 bar should net a healthy 350+ bhp and torque to match. Incidentally you can run two maps on the factory ECU, I change maps by holding revs above 4k and pushing the rear demist button.

 

Any ideas where i could buy a catless downpipe for MY03 JDM GDB-C Impreza STI? And what downpipe would you recommend?

What 3- point solenoid would you recommend? I found a GrimmSpeed 3- point solenoid for 113,00 USD. CLICK HERE

 

For downpipe i would recommend Hayward and Scott http://www.haywardandscott.com/subar...downpipes.html

GrimmSpeed are good 3-port boost,but MAC 3port are good too,cost less.

Jura

 

See if Fiesta boy (Rich) has any Prodrive 3 port boost solenoids available, one of the best available

Tony

 

Thank you for the replies.

I bought the vehicle few weeks ago and i'm not fully satisfied to the way it works at the moment tbh. But i think it will turn quite nice after some tuning.

Spool up, i think it could be improved a bit since i think turbo feels a little "sluggish" to wake up. I've read that the boost solenoid was a bleed- type so i think the spool up will improve after a proper controller. I need to fit a boost meter so i can keep my eye on the boost. When i should expect full boost on the roll at 3rd gear with VF37 twin scroll? What is the maximum boost? I also noticed some boost creeping during the 4000-7000rpms, especially in the beginning of the boost.

I made an order to Hayward & Scott for the twin scroll downpipe. They were very helpful and i hope the quality is good too.

I'm going to Ecutek my vehicle. I have one question about the emission control. I believe the mapper will disable the secondary lambda ('cause the CEL), but will he map the whole emissions control to closed loop- mode? Or will he just disable the secondary lambda and keep the primary working? The mapper is at vacation at the moment and wont be able to answer to my questions.

I'm planning to do these in prior of the mapping.

1.Downpipe (Hayward & Scott)
2.Boost control solenoid, to help the spool and controllability (Prodrive, GrimmSpeed, MAC?)
3.Replace the plugs, i had some problems running old ones very hot (Replacing with NGK BKR6EIX)
4.Make sure that the actuator works as it should, and replace it if necessary
5.Replace air filter

Is there something else what would be worth checking?

English is not my mother language so please excuse the faults in the grammar.

 

VF37 Max torque anywhere between 3500 rpm to 3950 rpm (on dyno), dependant upon each car itself & map.

Probably disable both lamda sensors.

Iv spent the last 4 months tirelessly trying to improve my JDM Sti & previous to that my Hawkeye SpecC. From what Iv learnt (the hard & expensive way! ) is:

Get it mapped after you have made sure of the following first:

-Fitted deccat/high flow 3" bellmouth downpipe (heatwrapped)
-Fit a 3 port boost solenoid (MAC is good but car wires need to be spliced, Prodrive is plug & play)
-Change plugs to one step colder NGK 7's
-Change to Cosworth or K&N panel filter
-Definitely buy e.g a Forge uprated actuator (blue spring), or you will waste your time on the dyno trying in vain to hold boost
-Change oil & filter
-Also check very carefully that there are no boost leaks anywhere e.g. boost pipes; intercooler; exhaust; exhaust manifold & up pipe.
-Ask mapper if boost cut on ECU can be set to an upper limit of 1.7bar. This gives some headroom for when you map to a peak boost of 1.55/1.6 bar. Though Im sure your mapper will already have it covered.

All the above will make sure you dont end up on the dyno every other week like me!!! Im back on the rollers again for the 4th time next month!! lol

ps your English is better than most on here who seem to write in Klingon or was that Rhomulin!!

 

Hello rickya.

Thank you for your valuable answer! I used to have few Evo's (V, VI TME, VII) and they used to wake up so much nicer. I also had an V4 Impreza Sti Type-R with BB turbocharger, and i remember it topping 1.0bar at around 2800-3000rpm. I could remember wrong too.

Could you clear few things for me.

1.Downpipe, why heatwrapping is preferred?
2.Solenoid, i will buy a GrimmSpeed or Prodrive then.
3.Just bought a set of stock plugs which are 6's. Would the heat range of a 6 be a problem while mapping? The vehicle is a daily driver and would not be used that hard on the street. Plus in the winters the temperature will drop to -35 so cold cranking requirements are needed.
4.Air filter is just changed with a stock one, upgrade necessary?
5.So an uprated actuator is a must, stock on with fresh spring wont work?
6.Oil & filter done
7.I can only diagnose the "clean" side, with pressure smoke- thingy!
8.Boost cut, okay. I need to ask him. There are not too many mappers around where i live (Nordic countries). And not too many JDM vehicles either.

I guess the disabling of both lambdas will worsen my fuel consumption?

And what was the stock boost in these?

-V

 

My 2005 JDM STI with a full decat Miltek Exhaust with wrapped down pipe, Green Panel filter made 333.7/365 on Subaru 4 You's rolling road with a map from JGM.

Everything else is stock.

Matt

 

Stock plugs on a JDM twinscroll are NGK7b's, 6's are stock on the EU 2ltr engined cars.

Heat wrapped dp is a must rather than preferred

Tony

 

1. Heat wrap is relatively inexpensive mod that will help keep engine bay temps down & flow exhaust gases away better. Worth doing especially if downpipe is new & not on the car yet.

3. 6's should be ok for this sort of power & tune though I would prefer to run with one step colder.

4. Replacement uprated panel filter is worth it & a cheap easy mod & flows air better than stock filter. No need to change airbox though.

5. I would definitely change the actuator, it will make mapping easier & takes a potential problem at mapping time, out of the equation.

7. Just have a good look around the manifiold heatshields & gaskets to up pipe & see if you can see soot or hear or smell a blow in the area!

Disabling the lamdas you will be running closed loop only at low revs & idle etc so wont make much difference in fuel consumption.

IIRC stock boost was about 1.4bar?

 

Lovely cars.

Simon

 

I see. I made a mistake by selecting plugs from the EU catalog. I tried to open Japanese NGK plug catalog, but obviously i couldn't make any sense out of it.

I'll have a word with the mapper which plugs would he recommend. Or then i could sell the plugs to EU- guys and get another set of correct BKR7EIX's. The mapping procedure itself will be the toughest condition for the plugs, temperatures are unlikely to rise that high on my driving.

1. Air filter
2. Downpipe + heatwrap
3. Plugs
4. Actuator
5. Solenoid

I will need to install/ replace those before i head out to the mapper. I will also check things that were mentioned previously and i think it would be ready for the map. He quoted me 250GBP for the Ecutek licence and 400-500GBP for the mapping itself.

Although all engines are different, but isn't that a little low on power compared to the torque? Weak actuator and boost drop in the high rpm? Dont know, just speculating.

What kind of power i should expect with those mods installed? I guess in healthy engine the mapping should take me somewhere around 350/350 mark, some have had even more.

I'll have to measure my boost since i think the actuator is not holding boost like it should. I feel a certain amount of creeping boost after it has peaked. Could be the original solenoid too.

 

I have seen power of Vf36/37's range anywhere from 320bhp to 360bhp. IMO 340bhp is about average & anymore is a bonus. (They are relatively small turbos compared to what is out there now). The torque is more what i would be concerned with & how quickly it spools up.

After trying different maps & using different mappers on my two Jdm's I can see that each have their own style of mapping. Some might say that the JDM twin scrolls are all about hitting peak boost quickly & shorter gearing, with emphasis on 0mph to 100mph. This does work by throwing in a lot of boost early, but just as quickly as these turbos hit that peak boost on a steeper torque curve, the quicker they drop boost. (even with an uprated actuator). So what you end up with is peak boost of e.g. 370 ft/lbs torque at 3900rpm but only for a short spike, after which it drops off rapidly. On the other hand Iv seen mappers feed in the boost a bit more gradually & less of it & then gradually building the boost. This does mean that peak boost comes in a few hundred rpm later ( & may only hit e.g. 350 ft/lbs) but seems to sustain for a large rev range, on a shallower torque curve. You could say its more usable day to day but I suppose on a drag strip you may think differently.

ps these are only my opinions & Im sure the Mappers will know more.

 

Agree with you.

Seen 360bhp 400lb but it was a brand new car, will find the graph later

Simon

 

After compiling together lots of various VF36/37 graphs from newages including a fair few of my own, the main thing that I think makes these differences in power & torque is engine compression & condition of turbo. (assuming all other components on the car are in a similar condition, which itself is impossible to say!). Both engine compression & turbo condition deteriorate over time & usage or mis-usage!

ps Have you considered JGM (posted above) to map your car, there not many people out there that know more about these cars than him.

 

Don't know but it drives very nicely

Here is the graph

 

Hey Simon.

Was that a JDM with exhaust & panel filter or a UK sti?

cheers,

Andy

 

Wow! And I thought -15 was cold in Skottland last winter!

You're English is rather impressive, as is your Scooby knowledge. Hope you enjoy your JDM (I have a 2006).

Andy

PS "Jog gillar Svenska scheyer!"

 

Good choice, but like I have said previously..... I would take advantage of the MegaROM functionality on your ECU with the EcuTEK software. It will probably cost you a bit more, but the driveability advantages are worth it in my opinion.

What a single gear dyno run doesn't show you is how your car reaches boost in the various gears and actually drives. Per gear wastegate control is one of the advantages of MegaROM and you can certainly see the difference that attention to this area provides on the road..... and that is where it counts.

You have the facilities available with your ECU, so my advice is to use them to their potential.

 

jdm spec c

found another one I did



simon