I am interested in the concensus view of the necessity for re-mapping after taking out the catalytic converter. I have had some correspondence with John Felstead on this subject with respect to my P1 and value his opinion, which is to do this even as a safety measure to protect the engine from pre-detting.

To quote John (and sorry mate if I'm out of order here!):

"P1's produce det spikes if you decat them, this isn’t where you probably expect either, it occurs when the boost comes on strong around 3300rpm and you can also get det spikes at around 4700rpm. You don’t need to be ragging them, just giving full throttle in 4th/5th from 2500rpm will produce these det spikes."

I am aware that there are plenty of Scoobs out there that have not been re-mapped and are going strong, even after several hard track days. I am also frightened by the fact that there is no end to horror stories on here about guys blowing their engine up, apparently after a series of modifications which include de-catting (?). Most(?) of those cars seem to be STis and Type-Rs, but I'm not aware of anybody wrecking their P1 in that way.

In my ignorance I would expect that the ECU would actually pick up those early det spikes that John refers to and then back things off in order to keep things as close to the limit as technically possible within the specs for the engine - is it only when this is too much (e.g., high revs) that the management system cannot cope?

When these cars are blowing up is it down to a fault with the original map or could it be something else, like a faulty MAFF or lambda sensor that is supplying wrong info?

I love my P1 and bought it with the de-catted system - I even love the sound of the TSL backbox . I want to keep this car going for a long time and am not that interested in giving it any more horsepower or torque (at least for the moment ...). Furthermore, it seems to me that I am in the wrong business when I understand that it costs £100's to re-map when most guys just write in a standard map - money for ole rope! - and I am loath to part with my readies for that malarky if I really don't need to.

What do you guys think?

Ta in advance
Canuck

 

P1's as far as i know,(after reading posts on hear), have a more active knock correction than Sti's or RA's, built into the ecu thus should be safer for the engine... do you have a knock link fitted? this would be handy in letting you know if the engine is detting so you can back off and take it easy with the motor... and are you running on optimax and not just normall unleaded? Optimax helps prevent det.. Optimax+ octane booster is better...

Sorry if i'm repeating things you already know..

I have n Sti Import.. its mapped to run on japanese 100 ron fuel so i have to run it on optimax +octane booster although many times i use only optimax but never anything less than optimax.
Its fully decated so i need a knocklink (bought one but havnt got round to fitting yet )

Use good fuel,service regularly and drive to enjoy thats what they are for if anything goes you can't stop it just be prepared to fix/replace it

 

Not such an issue on the P1 as on an STi, as it's at least corrected for UK fuel.

However, decatting it will still raise overboost issues and it's better to sort it. If you don't want to mess about with remaps or manual boost controllers then it's perfectly acceptable (going pre Dawes and EcuTek here ) to adjust the size of the restrictor in the boost control pipework. Probably replacing it with a needle valve is best. Lots of info on here if search goes back that far - 1.1 to 1.2mm restrictor should do the job from memory (stock is 1mm).

Richard

 

the p1 isnt corrected for uk fuel tho its just got a bit more welly with the knock control, map is aperntly the same (from threads ive read)

if your that worried, fit a knocklink, if it dets then have it remapped

easy

 

They don't all det and those that do tend to be from boost spikes which can be corrected easily by drilling out the restrictor by 0.1mm or so or fitting a needle valve as has been stated.

You can't though just fit a massive decat and ignore it when it spikes to 18 PSI as it does on some cars and then dets. Boost target is 15.7 PSI.

[Edited by john banks - 10/23/2003 8:19:14 PM]

 

I have known of three local ones go bang.... two were de-catted... one was standard...... so you pays your money... I would re-map anyhow... it'll be safer and cheaper than a new engine!!!

 

Agree with the above posts, however, with a remap you will sleep much easier.

Cheers,

George.

 

I stand corrected re. the fuelling, whoops

Richard

 

Interesting ideas here - looks like my comments about the relative contribution to faults re: ECU vs sensors seems to be so far ignored, so scrap that one (tho I would like to know how the ECU uses det spikes to monitor performance).

I have considered a knocklink, tho for the life of me I cannot see me hurtling along these brilliant B-roads we have in the East Midlands, to glance down to see if me LEDs are red or not !

Sounds so far that the problem could be idiosyncratic. Might be worth hooking the car up to one of those systems that monitors airflow etc to see whether there is a problem first. I am also intrigued by a statement I read yesterday in reference to fueling problems with imports (sorry can't recall who stated this):

"What you should realise though that over say 120mph the enrichment control contained within the ECU will not work as you have to disconnect it when you change the convertor. Imported cars are not designed to run continuously at higher speeds than 112mph.
Therefore if you are driving at over 120mph for long periods you "could" cause damage to the engine due the engine running lean as the enrichment is not working. A different ECU will assist with this."

Does this suggest that the problem is associated mainly with imports that migt have been sorted out by Prodrive with the P1?

Canuck

[Edited by Canuck - 10/24/2003 10:59:25 AM]

 

It could be down to many things... mechanical failure such as an oil leak which whould have nothing to do with the ecu.. or incorrect fuel...

The original MAP would be designed to run the car efficiently given that it is run using the correct fueling etc and thus it shouldn't be down to the original MAP causing the engine to go.
Failure of sensors like the MAFF and Lamda sensor can cause engine problems because the ecu will be relying on their input to make adjustments. Incorrect input would produce incorrect output thus causing incorrect mixture. Which Could cause engine damage.

Don't beleive everything i say though i'm a novice would be happy for someone to correct me if i'm wrong

 

I run my car at fairly high speeds (many times above 112) for Long distances.. havn't had any problems yet its done 52k miles...

You can mount the knocklink somewhere where its more visible.. many people on here would advise you get one then you know if your motor is detting or not

 

I'd recommend knocklink and lambdalink. You'll see the big red led, believe me

But it really depends how far you want to go - your original post suggested you just wanted a safe standard car. Drilling out the restrictor and investing in a boost gauge would give you this. Remapping just to correct boost maps (and maybe timing? I haven't worked on classic STi's here in CH) would be a waste IMO. I almost guarantee you'll want more later....that's the time for a remap

Specific to classics (bug eyes are much more advanced) - Your ecu is constantly listening to a microphone bolted under your intercooler. If it 'hears' detonation it will retard the timing in an attempt to stop it. It also learns this information so that it retards this timing always through those rev/load points.

I've always found its success to be variable at best - many factors seem to affect it's operation, to such an extent that I'm glad the headers I use means the thing stays out of my way permanently

The real issue, in my opinion (and limited to Euro classics, not STi's - a UK tuner would need to confirm) is a combination of factors; MAF's regularly start to under read...which tells the ecu to use less fuel and more advance because it's hitting a lower load zone. Not good if you're also overboosting. You wouldn't necessarily notice the difference - up to a point performance will improve.

For peace of mind, it maybe wise to sort the restrictor and contact an EcuTek tuner with experience of these cars to give it a once over to confirm airflow readings are OK for your boost levels?

Richard

 

Thanks so far to everybody - I am learning that P1 ownership is more than just driving around with a nice car (though the handling/performance was what I wanted after 3 yrs with a MY97 UK Scoob to teach me how to cut down on my seat valeting csots .

I have had this reply by email from John Higgins, who's agreed tp let me post it here - seems to me that re-mapping might indeed be the way to go for safety sake.
____________________
Quote:
[/b]Keith

I have a P1 with a Ecutek 3 remap by Bob Rawle (IMO probably the best mapper in the country).The Ecutek kit is so good that Prodrive now use it for all their STI8 PPPs - they generally won't admit on record but have ( Mike Wood "Daddy" of the P1 and the PPP) confirmed it off record.

In my opinion, any decatted P1 definitely needs a remap, although you can protect yourself to some extent by running with a minimum of Optimax and NF Race octane booster. I also have a knocklink, which was fitted before the remap, and it went crazy at two spots in the rev range as mentioned by John Felstead, despite also having an uprated fuel pump delivering more fuel than standard. You would also definitely notice it when the Big Red on the knocklink goes off, however twisty your roads are.......

Catted - it's OK but the standard P1 map is identical to the standard StiV map, except for a more sensitive knock correction added by Prodrive, which can handle the spikes when the car is still catted, mainly by relying on the standard overfuelling and on the retarding of the ignition - which loses you power and makes the car run roughly. When the car is decatted, the exhaust scavenging/ backpressure resistance is much improved with the result that much more air will flow through the engine taking it lean, which initially gives it more power but also shifts the fuel map ( the MAF reads how much air is going in and adds fuel to match, but it can only do this up to the limit set in the map) so that the two "thin"areas are now even more uncovered than before. The problem then is that with the right/wrong conditions ie load/ higher temps/ poor batch of fuel etc it will det it's head off in exactly the same way as a JDM Sti import. Plenty of P1s have died this way to the extent that IM/Subaru will not do any warranty work on a P1 that has had as much as it's airfilter changed, never mind the downpipe (if your dealer is one of those types that tells them.....) .

The Tek 3 involves, spending two to three hours sitting in your car and remapping on the road in real world conditions. Yes, they do initially flash in a standard map that he has gradually whittled down to be in the ball park for P1's through experience, but you then spend a couple of hours hooning up and down a suitable road to at say exactly 3k revs for a given time while he collects information on his laptop next to you , and then 4k for 3mins and so on, multiplied by all the different gears, plus hard runs all the way through the rev range to make sure that he has got enough info to stretch the map enough to cover you in all eventualities (gets interesting at 6K in 5th!!) - he will also adjust the electronic throttle openings and other stuff to make the car even more driveable.From that collected information, he reflashed a continually improving map into my ecu about four times in total from memory, with the end result that for around £700 I have a car that is now running about 325Bhp/300 ft lb (with no mods other than a HKS filter , full decat and uprated fuel pump), that is completely safe and very smooth. I had mine mapped with Optimax and NF, although you could go for just SUL or whatever you want. Still get the odd flash with the somewhat variable quality of Optimax, but it's sorted with a dollop of NF.Even dodgy optimax is still better than Esso or Bp etc which drive the knocklink mad.

Don't Unichip or any of that crap as they are a generic chip which doesn't take into consideration your car's peculiarities and every car is different.

To me £700 seemed cheap compared to a £3,500 engine rebuild.

just my tuppence worth - can't post on SN from work

John Higgins AKA Fat Boy[/b]
__________________________________________________ ____-

 

Some decatted P1s do not overboost, run lean or det. Some do.

Regarding fuelling the MAF ceiling is so high I don't think you could easily reach it on the VF28. It is possible to fall off the end of the fuel map, but the last column's fuel ratio is applied to the new airflow up to quite silly parameters. The ignition though continues at the last value because it is not a ratio that can be extrapolated beyond the end of the map like the fuelling is.

Factual inaccuracy re the Unichip though which may upset a few people... it is not crap, it is usually custom mapped to the car, and can achieve similar results to an ECU remap with independent control of fuelling and ignition. I won't say I don't prefer a reprogramming the actual ECU where possible, but the Unichip has a valuable role of some cars and can be extremely effective indeed.

There are also other methods than remaps to sort out some of these issues.

A remap is a great idea though, but the thread is asking if it is strictly necessary. Often it is not. If you are armed with a boost gauge and knocklink and are prepared to sort out any overboost and use the appropriate octane booster then you can get away without. Same on STi 5/6.

 

Sorry to butt in but i have an sti v2 and want to decat it...any problems like the P1 with boost spikes etc? I have gauges on order and am going to get a knocklink soon btw
Thanks
Stuart

 

Coulty,

No probs on that 1 m8, go on go on go on
Knock u r self out bud

Pete

 

if you are going to quote me keith, quote the whole email. And yes, it is bad form quoting private emails on a BBS without asking for permision.

This is what i wrote.....

Hi Keith,

Apologies for the delay in replying.

I will only give you one bit of advice on decatted P1's, get it remapped by someone competent to be safe. If you want some recommendations I'd be happy to let you know who I would use.

P1's produce det spikes if you decat them, this isn’t where you probably expect either, it occurs when the boost comes on strong around 3300rpm and you can also get det spikes at around 4700rpm.

You don’t need to be ragging them, just giving full throttle in 4th/5th from 2500rpm will produce these det spikes.

I am not going to reassure you that everything will be OK, because that would be irresponsible and you wont thank me for it should your engine fail. At the very least, buy a knocklink and see if you are getting the occasional ping, most P1's do after a decat.

So to answer your main question, (SO, my question is - Is a re-map STRICTLY necessary and if so what is the most cost-effective way?) YES it is if you want to be sure of safety.

Cheers
John

 

Well John, all I can say is that I'm sorry if you feel that my ommission of your final caveats in some way mis-represented you. I cannot see that the points you made either were lost in any way or somehow discredited you.
I appreciated your contact about this, thanks very much, and assure you that I won't post again your private comments.

Keith

 

[Edited by Abbylad - 10/30/2003 8:05:48 PM]