JonW

Fitted a Tek2 ECU with standard downpipe, centre and a TSL backbox and all was fine the first few times I drove it but I new seemt o have got my surging at 2500revs back when cold and the other day I got it to overboost (brief cut and thump under car) at high revs in 4th to 5th change.

I thought the Tek2 cured these faults along with hesitation?

Anyone got any ideas?

Jon.

P20SPD

iTrader: (1)

thoght the tek 2 was designed to work with induction kit and full exhaust.

Maybe this is what you need?

It cured my problems!!

john banks

If you had overboost before it needs to be fixed - the standard car does not overboost. Fix it before upgrading is the usual advice. An ECU cannot help non-ECU problems.

The cold hesitations are a JECS ECU fault and at present cannot be cured.

Iain P

Ecutek told me that the Tek2 should cure my overboost problem which occured after I fitted my de-cat centre section. My car was completely standard other than a Milltek backbox and interccoler hose upgrade. The car held 0.9 bar but could peak over 1.2. I was forced to fit an MBC to cure it. Not yet convinced the Tek2 would allow me to go back to the standard boost controller with such a large over boost swing.

john banks

That peak (0.3 bar) is certainly very large. Most cars with a decat system, induction and hoses would not overboost with a Tek 2, just as most don't on the standard ECU with these mods. However, you always get a few "outliers" of cars which seem to make less or more than is desirable - in these circumstances it is worth tweaking the duty cycle map or the restrictor. If you make the duty cycles a bit low, then you have more cars with lower boost but fewer overboost problems.

With the PPP I needed a 1.35-1.40 mm restrictor (rather than the original 1.20mm restrictor) to sort my overboost problems with a full decat induction and hoses. A needle valve instead of the restrictor is a nice thing to use to allow you to tweak the boost - they are only £7, easy to install and you can get the boost spot on, and then turn it back say 1/4 a turn for track or winter to stop any spiking if you want.

Now I am on 1.10mm restrictor for running 20 PSI held on a different turbo with a tighter actuator. The ECU helps to a degree but it cannot fix it if your boost control is completely out of the field - if it did then other cars would not make enough boost.

The Tek 2 uses an 83.1% midrange duty cycle and a 16.0 PSI target.

The AE800/1/2 uses 72.2% and 13.7 PSI.

The Prodrive uses 84.7% and 15.7 PSI target.

All use the same boost dynamics correction table for +3, +1.7, +0.8 and +0.3 PSI overboost which reduces the duty cycle over 12 % in the worst case or under 1% in the least error case.

Note the higher boost target but lower duty cycle on the Tek 2 compared to the Prodrive ECU - this means the Tek 2 suffers far fewer overboost problems than the PPP when breathing is freed up.

[Edited by john banks - 6/28/2002 7:17:42 PM]

Floyd

iTrader: (9)

Perhaps your pipes are clogged with oil and the wastegate is not operating correctly?

F

P20SPD

iTrader: (1)

MY 99T after about 1 year started to overboost quite badly with induction and full decat exhaust. it would run from 14psi to 25psi and then the overboost would kick in and boost would then stick at 7psi for a while. not being a mechanic or a techy i kept on taking it to the dealer for them to fix. as usual it would never do it for them, so replaced boost gauge four times, still same problem. anyway finally when to garage instead of wife taking it, demanded that i drive the car and would let them see what happens. mechanic plugged in their data reader, half a mile and "f**k me" said the mechanic as the boost on his readout read 25psi. goes back to garage tinkers with wastegate

answer stuck up with oil!!!!

sorted no more overboost.

Iain P

Nothing at all wrong with my 'bits' and working perfectly OK before the centre section was fitted. If I tip-in smoothly it doesn't happen but when pushing on it occurs. Worst condition is 3rd and 4th gear flooring throttle, lifting off and flooring again.

JonW

So sounds like I need to sort out the overboost...

Ive already cleaned the pipes and solenoid with carb/brake cleaner a couple of times and the first time was a vast improvement but the second time it didnt seem to help. How do I clean the wastegate?

John, The restrictors you mention, are the available off the shelf or is it a case of drilling with fine drills?

Ive now fitted an Itg filter, Scoobyport decat DP and Centre along with my TSL rear box. Car is better but does still overboost on occasion.

Shame the Tek2 didnt cure the cold surging, for some reason I thought Id read that it would.

Jon.

Floyd

iTrader: (9)

Jon

I think the surging cure was for the 3K revs hesitation once warm, which was suffered by AE802 owners, the TEK 2 sorts this out but not the cold bit.

The cold start rough running has yet to be tracked down (w.r.t. a cure) IIRC. IMHO I think it's a sensor problem that doesn't respond when cold (e.g. like the lambda).

F

john banks

Fine drill set with 1.3mm the first to try then 1.4mm. Maplin and RS do them.

JonW

Floyd, Interestingly with my 802 I never got the warm 3k hesitation... pay off was overboost i guess...

John, cheers i'll check out their site. how do you get the restrictor out of the pipe? and silliest of all questions - why bother with a restrictor at all?

Jon.

john banks

Take the restrictor out and you will find the solenoid even if wide open will only get you about 10 PSI.

Get it out by pushing a 2mm blunt long object down the hose without damaging the hole. Coat hanger is one candidate, various other options

ScoobySnack

I'm having great difficulty getting the pipes off the solenoid to clean it. Its bolted to the suspension turret on the drivers side...

Are there any photos around to help from someone???

Cheers

J

john banks

Pull harder (whilst gently supporting the solenoid )

ScoobySnack

Can't get me hands down the side............ I will have to remove the bracket that holds the solenoid in place........

J

SimonH

At the risk of sounding like a complete muppet but doesn't that sound a bit more like drivetrain shunt than overboost?

JonW

Hi Simon, For me its defo Overboost as Ive been round this one before, you can come out with me and feel it one day if you like... :-)

Basically you change up at high revs 3rd to 4th or 4th to 5th and engine cuts for a millisecond and you get drivetrain thump under the car, but its the cut that causes it and that is overboost.

John, Cheers mate I'll have a look this weekend, Jon.

SimonH

Okay John, if you've looked into it before then fine. I probably wouldn't know overboost if it bit me on the ****
I've had exactly that though which is why I asked - bit quick on the clutch followed by thump from under the floor and a lurch. Usually during some frantic overtaking when I forget about the redline! I've had exactly this and not had a flash out of the boost gauge.

ScoobySnack

Well I don't believe it..............................

Before getting me hands dirty I had to take the car for a final drive to work, the overboost problem seemed to be better. So I gave it a thrash over 50 miles......

The overboost has gone. The needle goes up to 19.5psi then back to 17.5PSI straight away..........

Now i'll wait for the Delta Dash software to confirm boost values (gauge may be out slighty) and collect some data.

Since fitting the intercooler 300 miles ago and getting overboost , has the ECU learnt to cope with this????????????


J

john banks

It may come back in colder conditions. A 2 PSI overboost is not optimal.

JonW

Simon, similar sounding problems but from what i can tell its the cut in ignition that defines the overboost.

hows that PPP going? Babber really rated his til he got the Tek2... {stir... ;-}

SimonH

Stirrer

Very pleased with the PPP; running it with a full decat and a peak boost of just over 1.3 (it was topping 1.4 last night what's that all about?? I've probably been sold an STi ECU and the car's about to blow up ). Just love the flooring it in 4th and still getting shoved back into the seat . Only snag with it is 100mph keeps appearing far too quickly......

Think I've mentioned before but my 801 and decat got me 257bhp and 236Tq at PE; Merv reckoned there wasn't much in it for the Tek2 except maybe 5 - 10 lbft more tq. No idea what the figures are now with the PPP - might pop down to PE again in the near future

JonW

who me?!??! :-)

It'd be interesting to do a back to back at PS with our cars one day, Neils printouts read 257 I think with Tek2 and full decat and ITG (all of which I now have on my car except i have TSL back box instead of SS one) but thats PS not PE... hmmm...

Agree shove in the back at high speeds is amazing with the new ECUs...

So what you gonna do about intercooler piping and Y piece? Shall we try and do a deal on two sets and save on some postage?

J.

JonW

John, Just reread your earlier post:

"With the PPP I needed a 1.35-1.40 mm restrictor (rather than the original 1.20mm restrictor) to sort my overboost problems with a full decat induction and hoses. A needle valve instead of the restrictor is a nice thing to use to allow you to tweak the boost - they are only £7, easy to install and you can get the boost spot on, and then turn it back say 1/4 a turn for track or winter to stop any spiking if you want."

I really like the sound of the needle valve instead of messing about with drilling etc, where can I get one of these?

Jon.

john banks

http://www.scoobynet.co.uk/bbs/threa...threadid=56487

EvilBevel

Maybe I'm missing something or really misunderstanding, but as far as I know, overboost has got nothing to do with gearchanges ?

It does happen more in higher gears (load issue), but you should be able to repeat it without doing any gear change at all.

Overboost would be something like "accelerate in 4th gear, and by 3500 to 4000 RPM the boost would swing too far before settling to the held value. So say 1.3 bar peak going back to 1.1 bar held.

Depending on ECU setup, this may or may not initiate the fuel cut.

It is very much car dependant, and the easy cure is *always* to fit a different kind of restrictor (bigger hole in MY99 and upwards), even on the STi7. The boost solenoid can only do so much.

Sorry if I'm missing something, the gearchange issue is confusing me ... Unless you mean it happens after you changed up, plant foot down again (so you are in the sweet spot for immediate turbo spool up, say 4000 to 4500 RPM ?) ?

But even then: with a hot car you should be able to "induce" it without any gear change at all.

JonW

Cheers John, Ive had a skim read and will give this a proper look when im back from my hols in a week or two.

Im guessing that a boost gauge would be very helpful when setting this up... I assume these just read off the same hoses so perhaps I should fit one at the same time...

Jon.

SimonH

JonW - I bought myself a Samco kit from GGR; it was about £80 all in. A bit pricier than some however GGR were great; phoned up and ordered it at lunchtime, arrived 0730 Royal Mail special delivery the next morning

JonW

Simon is that the hoses and the Y piece for 80 quid incl delivery?