Audi 90 - jobs to do - HELP?

[jogi730]

Following this years disasterous showing at GTI, I have decided the following needs to be done to the car.
Since the fitting of the large IC, the car has certainly lost it's pick up and go (even more so then the bigger turbo initially suggested - gone from 2500rpm to 4200rpm, and now with bigger IC 5300rpm).
So first step will be to revert to the old IC, but to offer similar engine cooling, with a
water spray IC cooling system (maybe snowperformance)?.
Once this is sorted, the following step will definitely be to fit a 6 speed g/b.
I am thinking of possibly opting for a 6 speed diesel g/b? This is a stronger box and has longer gears than my current 016 g/b. This box is incapable of giving me 60 in 2nd. Any advice on this and what other parts I might need to do this conversion ( I do have a 3.89 urq rear diff if this is necessary)?
Is this a stronger box with longer 1st and 2nd gears?
Thanks
Chris

[amanda]

Hmmm the only gearbox that I know that will do 110 is 3rd is a caviler v6 2.5 one, it also ticks your boxes as well...........dont think it will fit an audi though

[jogi730]

Hmmm the only gearbox that I know that will do 110 is 3rd is a caviler v6 2.5 one, it also ticks your boxes as well...........dont think it will fit an audi though

Errrrrr...... thanks!

[S2central.net]

@Jogi

The 01E diesel boxes are stronger alright. Dont have specs in front of me, but when you see the torque figures for the cars using those boxes in stock trim its good.

I'm pretty sure the other aspect to consider with the diesel 01E boxes is a transmission oil cooler. I assume the oil is pumped mechanically, but it could be an electric pump.

There are some diesel 01E boxes with particularly high gearing if maximum speed is your aim - the old 016 5 cog is somewhat lacking in the gear spacing department. I have a gearing calculator somewhere that I produced to give roadspeed indications at the redline.

A gear space ratio *difference* of a factor of 1.5 is a pretty good rule of thumb to look for on a quick road car... This equates to changing up a gear at 6000rpm to put you on 4000rpm for the next gear.

Think there is something on this topic at S2central.net

[Rusty]

A CO2 IC spray or N2O spray might suit you better as it will freeze the IC before the sprint rather than just dampen it! Water sprays require air flow to work really well. A very quick search showed this up. I have not done any research into this for mine so have a look around. There's also the option of running water injection to gaurantee you low charge temperatures.

From what I've read whilst researching a different thread, the IC increases the density of the charge whereas water injection decreases the charge temp and cools combustion, allowing a more aggressive map to be run. The two do different jobs but cooling an IC of any size is a good idea.

Snow perfromance seem to have been the choice of a couple of people on the forum and they offer a wide range to suit every pocket.

Sorry, don't know much about what gearboxes fit the typ85, does an ABY or B5 S4 box not fit? Both will do 100 in 3rd but with your beast that's still not enough! S2 5 speed gearing is better for sprints from my experience 2 weeks ago, shame about the strength issues.

Good luck Chris, I hope that you get the car sorted soon

[S2central.net]

Cold air is what we want getting sucked into the engine... Its Boyle's law stuff - colder air is more dense than warm air... So if you can get the air colder by have a bigger/more efficient intercooler then its good... If you can also cool it with assitance from water injection then that is good.

The hotter the air intake is, the less aggressive you can be on ignition timing... Or you reduce boost to compensate for potential knock issues. And what is boost directly proportional to on any turbo engine - TORQUE !


Paul

[20Vcqdriver]

Use the later S2 6 speed, it virtually fits straight in and have a source for all the adaptors you need to get it too mate up with the rest of the Type 85 bits. Present rear diff ratio is the same as the S2 6 speed (assuming the 90q and my Coupe q use the same diff) so everything can be kept. Basically use an adaptor/spacer from our prop to the S2 box, swap over our gearbox flanges after removing 3mm from the spline end first and mix and match the gear shift linkage to mate up with what we have already. QED!

[Rusty]

Sounds simple Well worth it on yours Chris, it'd transform the sprinting ability as the 90Q box has far too short ratios for the power you're running. If the later 6 speed fits then does that mean that an S4 box would fit, if you could locate the oil cooler somewhere covenient.

Took me quite a while fitting an OE box to a 90Q typ85, quite a heavy box of tricks when you've only got the car on axel stands

[jogi730]

The diesel 6 speed out of 2.5 A6 had a 3.89 ratio box I do believe? This would improve sprint times further still would it not - although ultimately I want drivability. Also it may be a cheaper option from the breakers?
Has anyone done this conversion or know where to get it done?
Cheers
Chris

[kwlw]

Is it only me, who doesn't believe, that fitting bigger IC moved power peak for a thousand RPM?

Maybe you have simple boost leak ? Was the system pressure tested?

Joggi, do you have dyno plot for your car?

Sau

[jogi730]

Saul,
Here is link to dyno plot for the engine (it shows new set up - T61, against old T34).

http://www.s2forum.com/forum/showthread.php?t=14487&page=5

This was mapped with the old, smaller IC. There was obviously much more lag, but coming in at about 3700 and being on full song by 4200 was livable. At 5300 its much worse and almost a waste of time, especially in London.
Cherrs
Chris

[Jamo]

Is it only me, who doesn't believe, that fitting bigger IC moved power peak for a thousand RPM?

Maybe you have simple boost leak ? Was the system pressure tested?

Joggi, do you have dyno plot for your car?

Sau

Large IC means larger volume for the gas to fill and also induces a pressure drop across the IC.

[Rusty]

The IC is huge, perhaps having it reduced in size might be an option, or run the turbo at lower presure so that it does not require as much RPM/exhaust gas to reach the boost threshold. The latter would drop power but would also make the car more driveable in the mean time? 5300 does seem fairly high but it is a massive turbo and the IC will really not help in the lower gears... smaller turbo? Perhaps a GT3076 to fit onto the existing manifold?

[kwlw]

Large IC means larger volume for the gas to fill and also induces a pressure drop across the IC.

I wouln't call this intercooler huge. People run those with smaller engines. Maybe poor quality tube/fin's inside, which are hurting the flow? Or the piping has been made dramatically different and restrictive?

1000rpm is 36litres of air per second. It's quite a difference. Too huge to blame just size. That's my point. Maybe timing and (or) fueling are too conservative for colder air or something.

Also that state of the art boost control system. It's interesting, can it be tested somehow, to ensure, that it is working properly? As I've read here, it is difficult to setup, maybe after adding intercooler it is not functioning as it should?

Maybe I sound too stupid, but I cannot believe, that engine, with turbo, famous for fast spool up will full boost only at such high rpm as 5000. Something just doesn't fit here . Experts, can you comment this issue?

Sau

[jogi730]

Is it only me, who doesn't believe, that fitting bigger IC moved power peak for a thousand RPM?

Maybe you have simple boost leak ? Was the system pressure tested?

Joggi, do you have dyno plot for your car?

Sau

Anyone know where I can have a boost test done in/near west London?
This could be worth investigating.
Cheers
Chris