hackish

Nobody in North America seems to have a clue about what the STi IV engine/ECU has or doesn't have so I thought I'd skip across the pond to ask you folks who may actually own one...

I have not gotten my Impreza 2.5 RS back yet with it's new STi IV transplant. One question I have is about this speed limiter. First, is there a speed limiter? If so what would it be set at? I've heard figures as low as 100MPH which isn't that unreasonable a speed on the public roads. Other figures I've heard were 112MPH and 136MPH. 100 and 112 are not unreasonable for the track as there is a long straight where some people get 125mph+.

If there is a speed limiter, how can it be removed?

-Michael

StingerSK

Well, I can assure you that when they say the MY02 is limited to 130, it is a lie It is, in fact, limited to 136(had it there).

I'm not sure about the STiIV, however. Hopefully it's limited to the same as my MY02

hackish

Is that 136 via your speedo or GPS? I find the speedo to be pretty accurate but at 160kph (100mph) on the speedo it's actually only doing 155kph.

-Michael

ChristianR

iTrader: (1)

my sti iv was limited at 112mph by Japanese Law.

you can easily get de-restrictors for it, so you can go way past that

I managed to hit 160mph, in 5th gear at 8000rpm(hitting rev restrictor)...

(sti iv type-r coupe)

[Edited by ChristianR - 1/13/2002 11:17:45 PM]

hackish

eek. Imagine that, on the long straight at the track I'll be beaten by 165hp 2.5RSes. How does one remove said speed limiter?

-Michael

ChristianR

iTrader: (1)

Japanese Speed De-limiter... £195

http://www.powerengineering.co.uk/su...cts/engine.htm

hackish

Anyone know how these units work? I suppose tricking the ECU as to the actual speed is one thing but making the gauges work correctly is totally another. I've searched the web a little looking for this answer, but does the unichip also remove this limitation?

-Michael

Paul vL

Jap spec cars are limited to 112mph (180kph). The delimiter gizmo just converts the speed signal to mph from kph. So when your speedo reads 80 you are doing 80mph and no longer 80 kph. The new limiter is therefore set at 180mph. You usually get new speedo decals in the kit to make it less confusing. Your odometer continues to read in km however.

I thought the highest grade fuel you could get over there was 92/93 RON. A jap spec STI ECU is mapped for 100 RON so you would be asking for trouble if you ran it on 92/93 RON. Some people have burnt out pistons using 95 RON in the uk.

cheers,

Paul

hackish

Oh, that's really dumb I was expecting them to at least chip the ECU with just the speed limiter disabled. I think I'll design my own speed limiter bypass unit. I'll just cap off the speedo signal and build my own speedo controller. I don't think it would be that complicated. That unit wouldn't work on my car anyway since I've still got the North American gague cluster.

Our fuel is measured differently. I can get 94 octane which comes from (RON+MON)/2. This is pretty close to the jap 100RON fuel. There are plenty of people here running it with no problems. If worse comes to worse I can get 110 octane race gas by the barrel for about $2.00CAD per litre (from what I've heard about the same as the 1.00GPB/l you guys pay for normal fuel).

-Michael

hackish

Ok, did some more reading. On the Canadian 2.5RS the speedo signal gets split and one goes to the ECU and the other goes to the gauge cluster and it calculates the actual speed. The wiring for the STi is a little different. Can anyone confirm that the same thing happens there? If this is the case I'm sure I can just take the ECU signal and build a DIV/2 with a simple digital circuit. Thus the ECU would believe you're going 1/2 the speed you really are.

Does anyone know if the stock computer limits boost in 1/st gear? If so this mod would probably confuse the ECU into limiting the boost in the first few gears.

-Michael
-Michael