Shaun

Recently this subject has been talked to death, but with no conclusive evidence.

Personally, I understand that all import scooby's could have a problem with detting (as other people have quite rightly pointed out, that these cars are set-up to run on 100+ octane fuel).

The only sure way of curing this problem, would be to have the ECU re-mapped to account for the decrease in octane, i.e. retard the ignition. This would have the downside of decreasing available power.

Has anybody out there had this process done, and to what level was the power descreased from the "before" figure?

I am in the process of having a UNICHIP fitted to a 94 WRX and from information supplied, I should be expecting 280+ BHP - the only other mods the car will have is a different exhaust system & HKS induction kit. Based on other people's experiences, is this a reality?

How much horsepower would one expect to lose from a standard car pumping out 240 BHP on 100 octane fuel, as opposed to a re-mapped standard car on 97 octane? Is it mega or negligable?

Comments appreciated.

RobMac

Shaun,

You could fit a 'Link - ECU' which is customer re - mappable to overcome the problems with using UK fuel.

This has been done in a few cars that I know of, and the performance was fairly close to standard. Albeit in a different form. You adjust the boost a fraction and re - map the fuel at various points on the revs to take into account the new fuel grade.

I'm sure other people on this BBS will tell you more than I am able too.

Rob.

harj

Shaun,

I too am interested in any findings regarding Shauns questions as I have had a Unichip fitted but Power levels are much lower than anticipated.

Harj
WRX

IWatkins

harj,

Unichip, where fitted and how much increase did you get ?

Cheers

Ian Watkins (GT4)

Paul Wilson

I had a Power Engineering remap done on my car on 95RON fuel, and power increased from about 250bhp to 284bhp, however I run the car on 97RON to provide myself with a safety margin.
My advice would be to speak to(in no order)
Power Engineering
Scoobysport
ScoobyMania

and then to make up your own mind.
Mail me if you want to chat about your options, I can't promise an unbiased view, but I will not give you any bull.
Paul

Unconnected with any company

Shaun

Harj has got a slightly different query to mine.

His car in fact measured 260 BHP after UNICHIP (1.4 bar boost). The car was supposed to be kicking out 280 bhp standard, but not proven.

I think even Harj will agree with me that the fitting of the UNICHIP cannot be made the culprit for this. When Harj had the work done, he should of had the car rolling road tested beforehand to have info. to gauge results on.

I would not expect Harj or myself to divulge who did the work as this would have an unfair reflection of the company/products involved.

One point worth making though Harj. Don't forget there had been nearly ten runs made in 1 hour. This would most definatley account for a loss of upto 20+ BHP on the final figure given - you could of cooked an egg on the intercooler!!!

And don't forget it did feel alot more powerfull on the way home.

Shaun the bouncer

IWatkins

Shaun and Harj,

I only ask becuase I also have a Unichip fitted to my GT4 and was after your impressions.

Cheers

Ian Watkins (GT4)

harj

Actually I am very impressed and pleased at the cars performance now, the car feels so much smoother and quicker to what is was before. The Torque figures on the rollers were 265lbt when it was at cooking point, and yes you could have made a complete Fri-up on the Intercooler. I'm now looking to get it upto the 350BHP mark, I take my hat off to the guys that completed the work as they certainly know their stuff.

Harj
WRX

Shaun

Ian,

I imagine that you have had your UNICHIP fitted at the same place as Harj went and I am about to.

Is yours a series 1, white one?

Again because there was no factual figures on the standard car output prior to re-map, no conclusive results can be given, regarding the cause of the lower than expected output.

I think the key factor here was the heat soak, that would of naturally knocked the figure down some what.

The main point is that Harj's car is pumping out a base figure of roughly 280 BHP, with no DET problems. Surely this is better than 320 bhp and a whole in the block!

I am also aware of the differences in calibration between one rolling road and another. So where as one conversion by one company on there rolling road may give one figure, a different conversion on another rolling road cannot be directly compaired.

Paul,
I find it quite strange that any conversion mapped for 97/98 octane would give less than the same conversion remapped to 95 octane.

Is'nt the higher octane supposed to cool things, aiding combustion!!!!!!

Was the original map done properly in the first place!!!!! The only explanation is the first map was throwing in too much fuel, and the second re-map made adjustments, which was corrected on the second re-map.

Was there any changes in the ambient temps. of both mapping sessions?

It's also probably worth saying, that any mapping should take place within the coldest part of the year. If an engineer maps an engine in the summer (high intake/ambient temps - lower than optimised boost actuals), when the winter comes (lower intake/ambient temps - possibly higher boost attainable)there is a strong reason for detting, as the fueling would not always be correct for the new peak boost.

I am still in the need of any feedback relating to the original thread!

IWatkins

Hi Shaun and Harj,

PING !

It all comes clear. We have actually met. I was there when Harj was getting his Unichip fitted.

(Ian goes back to sleep )

Cheers

Ian Watkins (GT4)

MorayMackenzie

Shaun,

I believe that your "all imports det on lesser fuel" statement may be a little too general. My STI III (Standard but for exhaust+filter) is not detting on 97 ron fuel. The car it is increasing it's boost to 18/19psi, which it won't do if you feed it 95ron (I don't) or you get a bad batch of super (I have done ) where the boost will be retarded to ~14psi max.

BTW: My car produces 290/295 bhp at 14psi.

Moray

MorayMackenzie

PS: That's a 290/295bhp on Rich & Dirk's RR.

Shaun

Moray,

Not trying to pick a fight, but.....

How can a standard STI, boosting at 18psi be able to hold these levels ***** out without pinking on 97 octane petrol - without an ECU re-map? We already know that worse lesser quality fuel will make the ecu retard ignition. From my understanding an import STI car would not be able to hold the standard boost (is it 14 or 18 psi), as the ecu would detect the lesser fuel (97 octane), and would automatically reduce boost & retard ignition.

Is this right or am i p!ssing in the wind

Am I right in saying the standard boost is 18 psi?????? or is it only 1 bar. I am assuming that a standard STI boosts at 18 psi for a fuel of 100 octane.

[This message has been edited by Shaun (edited 05-03-2000).]

[This message has been edited by Shaun (edited 05-03-2000).]

JON HUGHES

Shuan
I think if you read moray's reply again you will see that his car is not standard,it is fitted with a diffrent exh and a blitz filter.

As Moray was saying about his boost pressure's being 14psi and it being 18psi now,I would think this was due to the size of the restrictor's in the pipe to the solinoid vale.As i understand it moray had removed his remapped ecu and replaced it with his std one,the restrictor would of been there to stop the the over boost that the modded ecu might of caused

My sti used to hold 1.1bar std with up to 1.5bar of over boost,with no det problems(std apart from exh&filter)which also made 285bhp at powerstation

Why don't you get Rich at PS to give you a before and after reading,even if it means going back the next day to avoid any heat soak or drag?

Starting to ramble now,thats what drinking in the afternoon does to you

Jon


[This message has been edited by JON HUGHES (edited 05-03-2000).]