ClintUK

Classic UK '97
Standard TD04
Flowed OEM manifold
Single sports cat wide throat down pipe high flow system.

I'm thinking of upgrading my turbo to give me more mid range grunt and a little but not huge top end power. I don't want to rev the nuts off it as its done 105K

Am wondering about Andy F hybrid TD04 or a TD05 option.

My main question is, when chaning the turbo, do you get gains without a remap ?

I'm on standard ECU and I'm wondering if the standard map says give 'X'psi boost, chaning a turbo to give more will only be effective if the ECU map is upgraded to suit.

Is changing a turbo effective before having a remap ?

Thanks

scoobfan

A remap is required when a larger Turbo is fitted, if not it may result in the engine running lean and melted pistons !!

Reason being it pushes more air.

Regards
Rob

andy97

iTrader: (1)

For the 97/98 car you will need an apexi fc( mapped) to run a bigger turbo safely!

ClintUK

Doesnt the MAF register the increased flow and the ECU increase the fueling to compensate ?

New_scooby_04

iTrader: (4)

A new turbo would most likely be outside of the ECUs capacity to compensate: at the best you'll have a turbo operating below par, at worst it'll kill your engine (there is a post on here at the mo from a bloke who'd just had an engine failure as a result of running a TD04 on a TD05 map).

For a car with 105 on the clock, I'd steer clear of the TD05, as they can eat gearboxes! Your best bet would be a modified TD04 Hybrid or a VF series turbo from that model year Sti I'd imagine.

You WILL need that remap though.

Ns04

scooby_matt

It might be worthwhile looking a vf28.
Similar spool up to a TD04 and you can get hold of them fairly cheaply.
Less potential of smashing the gearbox than the TD05 aswell.

dogpole

i went from a td04 to a vf28 and got 300bhp / 290 ib/ft on the first mapping session.
thats with the standard tmic.

my99 uk turbo.

New_scooby_04

iTrader: (4)

How does the VF28 turbo compare in terms of the shove in the back and response to the accelerator to the TD04 mate?

Ns04

jaytc2003

iTrader: (1)

The MAF monitors before the turbo

Not true, the engine blew and it was found to have a td04 instead of a tdo5. It is not known yet why the engine blew, and it is highly unlikely that the wrong size turbo contributed to it, speciially considering the speed at which the engine went. 80 to 85mph in 5th so about 4000rpm, not exactly stressing the engine.

Clint, if your car has had regular services and oil changes etc and is in good general running condition, then even with just a remap on that turbo you can experience more of a kick. The boost will just tail of at the top end but it will be a smoother (depending on mapper) drive. A tdo4 should be good for about 280ish bhp

Rich_B

iTrader: (6)

True, but it still measures the overall air consumed by the engine.

New_scooby_04

iTrader: (4)

You're quite right, the cause has yet to be determined, but David from API said it's likely to have been a big factor and that the different maps between the two would potentially be a big problem, so I'd say it wa a good probability that this was at least one of the culprits.

Wouldn't 4k rpm be roughly where the engine is working hard to produce its peak torque? So would it not make sense that this happened under conditions where that engine speed was maintained IMHO.

Ns04

jaytc2003

iTrader: (1)

your right in what your saying, but also the turbo at that rev speed would be well within capactiy as it wouldnt be stressed at all and so would still be supplying correct boost levels.

I can only speak from experience (my own) as I say I have a smaller unit than the td04 and it holds 1.15 - 1.2 bar in fourth and fifth comfortably

I see what your saying, but by adding a bigger turbo its not putting in more air into the engine, it will change the way the air is delivered into the engine (longer to spin up so a lag effect)but it won't add extra air to what the MAF has already metered.

john banks

It will put more air into the engine that the MAF will meter just fine...

Home made FCD and a Dawes, Magnex 3 to 2.5" exhaust with PPP backbox, fuel pump, aftermarket TMIC and a hybrid TD04 saw my MY00 hit over 290 BHP and lbft without a remap. An AE802 ECU map and many of the others will fuel until you hit the limits of the injectors/pump/MAF, but some will run too much timing. Fuelling was safe and it did not det, also put it around Knockhill like this. I ran it at 21 PSI with some octane booster. Engine lived through loads of abuse after that and was sold working to upgrade.

jaytc2003

iTrader: (1)

ok maybe explained it wrong but what i meant is ithe air that it puts into the engine has already been metered, it wont magically add more air (unmetered)its just the delivery of that air that has changed ie max volume for longer duration

ClintUK

John

Very interested in your comments about ECU fueling until one of the system components is running flat out. This seems completely logical to me.

Any idea where I could find out if my ECU 1997 vs your 2000 has a similar map ?

I have a mod in mind but need some reassurnce that what you said is OK for my ECU. Comments by Andy F seem to agree with this albeit with some engine safety checking suggested.

One further question, adding a high pressure fuel pump. I assume this doesn't increase pressure in fuel rail as this is regulated, but maintains pressure in the fuel rail, when injectors are demanding more fuel.

Thanks

jaytc2003

iTrader: (1)

if you have a standard regulator on at the moment, a high pressure pump can possibly overpower the regulator which can cause a bit of overfuelling (depends how much the regulator is being overpowered) mine is slightly overpowered by my fuel pump but the ecu has been mapped around this.

SiHethers

Clint

I ran a vf34 at 1.4 bar (20 psi) on an standard tmic MY99, ae802 ecu without a remap for around 12000 miles. To do this I had to fit a walbro pump and increase the static fuel pressure, in addition to using octane booster/methanol, and retarding the ignition timing 2 degrees (with delta dash). Monitoring was via knocklink and wideband AFR. Boost control using a Dawes MBC and FCD. Before this I ran the td04 at 1.3 bar on the standard pump and fuel pressure, but again with OB.

Now the car has a PFC running 1.5 bar (on OB) uprated tmic, ported headers and a few other bits and bobs now, and has survived 94000 miles. The standard gearbox didn't last long at 1.5 bar though

I think your limiting factor will be your injectors which I think are 380cc in the UK MY97/98. A fuel pump and pressure upgrade would be pretty essential. You pump is likely to be tired anyway (mine was leaning to 12.5:1 at 6000rpm at 1.4 bar before the upgrade, and this with a FPR and 4 bar static fuel pressure!!)

Another thing to consider is that I think the MY97/98 ecus run similar advance to the ae800 in the MY99, so it may not be possible to accomplish without a lot of OB for this reason. The ae802 ecu I used is 4-5 degree more retarded as standard.

Simon

john banks

The low octane maps are more retarded, but IIRC the high octane map is still OK, the reason for the power difference is fuelling is slightly richer and boost slightly lower.

Uprated fuel pump just keeps the pressure up at high flow levels. The return hole in the OEM MY99/00 reg and probably some others on GC8 is a bit small so that at low flows your pressure can rise a bit. Typically the lambda sensor will sort it out, but not always.

ClintUK

Thanks guys

I understand most of this advice, think I'll go ahead with my little experiment - I'll let you all know what happens.

I know I have to save up for an Apexi at the end of the day though.

Thanks again

Andy.F

Whatever you do Clint, as previously advised just make sure you get it checked by someone with a wideband and det cans. Sometimes a splash of octane booster is all thats required to save any heartache.

Andy

easyrider

Andy

Would monitoring the AFR's on a bugeye with a SECS be ok-as it allready has the wideband.(also monitoring with knocklink)

Gary.

Andy.F

It has a wideband of sorts Gary but it has a base line of 11.1 AFR which does not always match with my wideband for some reason ? On my own 03 WRX it does but I've come across customer cars that have run much leaner yet the onboard sensor is pegged at 11.1/11.2

Still worth on any car getting a check of AFR and also ensuring your knocklink is working properly. Any of the tuners can do this for you and I wouldn't expect to pay too much.

Andy

easyrider

Thanks