Audi A3 1.8T

The history of...

2010-07-14T11:05:00.000-07:00

This blog is about a car with 1.8T engine well known from VW-Audi Group cars. The idea behind it, is to increase the horse power of the engine with software and hardware adjustments, in order to achieve one nicely looking car, /although modest one in nature/ with decent characteristics in ½, ¼ mile and maximum speed. The engine is very popular around the world and can be found in number of cars: Seat Toledo/Ibiza Cupra/Leon, VW Golf IV, Bora/Jetta IV, Skoda Octavia, Audi TT/A3/S3. Depending on which side of the globe you live in, you can get some of these, and in some cases all of it. There is number of different engine codes associated with this type of engine, and in our case we've got AGU code, mounted on A3, made 1998. It's 150hp setting, with front wheel drive.
The same engine with minor differences can be found in 150/180/209/225hp settings on different cars.
Considering the fact that our car is front wheel drive, there is a better option to switch it for: Seat Ibiza Cupra. With it's lighter weight, and same engine, it will give better times with same modifications. However, having in mind that Audi TT/A3/S3 and some Golf/Jetta/Bora are 4x4, there are quite nice alternatives. In some countries you can even find Seat Leon with 4x4, even though it is pretty rare vehicle.
The first mods that we made were to modify the chip setting of the CPU. With the removal of the cat /in our case/ or switching it with high flow one, you can get around 180hp from it. At ¼ races against Opel Astra, Golf II with KR engines, or III with 16v, Civics with VTS, or similar platforms, the Audi always takes advantage. Sometimes with more, sometimes with less, it always ends first.

After a few good months with that setting, we decided that we need more from it. First, we were thinking that 280-300hp is the most we will squeeze from that particular car. This can be made in two different ways: switching the turbo with the one that 225hp applications use, or installing bigger one, which can get us more /maybe 400-500hp/ and not push it so hard, so we can get the same setting.
The first option is almost 'bolt-on' ,with minor mods. The second ,and the one we choose to be, is more difficult, but if eventually one decide to increase a little bit more, there is always a easy way to do it.

The most important part of it was the turbo. We've got a T3/T4 back at our garage, so we used that particular one. The manifold we ordered, was some ebay cheapo, which caused us a lot of troubles at some later stages, but, for the time we taught that it will be OK. It was log-type, which isn't the best choice for this car, but I will mention more about it later.

Control of the turbo was with manual boost controller, and the intercooler /FMIC/ was 550x180x65mm in size. The piping of it was 2.5”, and for exhaust system we used 3” with only one muffler at the end, with that same size.
Blow off Valve Greddy ,Gauges for fuel pressure, boost and oil temp. Bosch Green top, high impendance fuel injectors, with fuel pump very similar to Walbro 255. Walbro is most used, but we've found something cheaper at that time, which worked perfectly.

After around one month in the garage, all was mounted on the car. Besides of everything described, we mounted Weitec 40/40mm springs, and new gas shocks, to improve stability.
Also, we switched the original engine bushings with new ones, made from polyurethane. This, together with stiffer suspension, made the car pretty rough and vibrating, but it handled very differently after. The original 15” rims, we changed for 17” with relatively high ET, which made them stay 'inside' the feners. Not only that, but they were pretty heavy. We didn't had anything better, but at that point that worked well enough.

After all that, we started it for the first time, and prepared everything for first test runs.

Copy/paste links in your address bar to see the first start and one test run of the modified car:

http://www.youtube.com/watch?v=4MTAqpwjl2M

http://www.youtube.com/watch?v=sJdUMLooQwk

The First Setup

2010-07-14T10:49:00.000-07:00

The first setup we made was with boost setting of 1.3-1.4 bars. The manual boost controller isn't very reliable, especially the overboost was quite frightening for us a the beginning. It easily can jump a lot higher than expected, which eventually can damage some engine hardware. Expected horse power with this setting is around 260-280. However, at that time, the closest dyno was pretty far from us /300 miles drive/, and that left us with only assumptions on the exact power. Overboost peaks we noted was at 1.6 tops, with regular 1.5s or so. Spool started at 4000 and at 4500 you get what you should. RPM limit was set at 7500, due to the fact that we used only stock engine rods and pistons. If you want more from this car, you gotta change those. Relatively late spool of the turbo, and front wheel drive, left you with no other option but to drive the car to the limits of the RPM, especially on 1st and 2nd gear.

After a few runs we encountered first troubles: weak gaskets around the manifold, some cracks over it too, and some piping adjustments, because it wasn't at the proper place and rattled from time to time.

We've changed the gaskets quickly and easily, and as far as the manifold problems, we just welded the cracks, just until some better solution comes up. We made some trial runs with G-tech, and we've got 13.4-13.6 at ¼ mile, with slight angle of the road, in negative favor. In other words: slight hill.

As comparison: at same strip, Audi S3 225hp, with high flow cat and software mods /270-280hp expected after that/, gives you 13.5 measured with that exact same G-tech, having in mind that due to it's quattro, it provides perfect launch.
As for maximum speed performance, check out the videos below /copy-paste in your address bar/:

http://www.youtube.com/watch?v=gnu4P-uexl0

http://www.youtube.com/watch?v=CzFCRB9teiU

Second Setup

2010-07-14T10:33:00.000-07:00

It's easy to get used to the nice things. It's even easier when it comes to the power of your car. And you get to want more and more from it. However, it's not so easy nor cheap to increase the horse power. And almost never ,equal to the amount of time you shorten on the drag strip.

One thing is certain: the cash amounts you're investing, are growing in geometric progression. For example: if you want to drop your time from 14 to 13.5 for a ¼ mile, you invest, we say, the sum X. However, if you want to go from 13.5 to 13, than the sum you need isn't X anymore. It is X times two or three. Not only that, but the risks of damaging something are higher too. The more you want, the more you pay, the more your chance of getting something wrong is bigger. Tough math, eh?
In our case, we firstly got our gear box damaged. Anyway, with a little luck we've found a similar one pretty quickly, just with minor discrepancies: The old one, had a wider gear ratio, gaining almost 270 at fifth gear. The new ended at 245-250 km/h. That's better when you use it for ¼ mile,and besides, the new gearbox was somehow tougher.

In other words, after a long time of minor adjustments, re-tune and problems here and there, we've decided that we need another setup for the car. That gear box problem I mentioned, was actually entirely our fault, because we've postponed the installation of a tougher clutch, as long as we can, to save some money. That was a big mistake.
Firstly, after analyzing the situation, we've decided that we need to lose some weight, so to gain more from the initial setup. This is common with fast vehicles: aircrafts, bikes,cars, boats: you need to be light in order to be fast enough.
So, we planned to get rid of everything that we don't need: spare tire, first aid kit, rear seats /only the lower parts of it/, and stuff like that. For example, if you change your battery with smaller one, similar to the ones they use in sail boats, you can cut 15-20 pounds, only from that. We've planned to install sport seats too, but after all, we didn't.
We made minor adjustments to the security. For that, we installed Brembo rotors /standard ones, with no drills or slots/ and new brake pads. Changed some of the hoses of the brake system, and it's liquids. We needed to have a car that can not only accelerate fast, but also to slow down quickly enough.
The other small stuff that we've changed ,were bigger air filter, Forge Blow-off valve /more reliable that Greddy, due to the fact that is 100% genuine/, a silicone hump on the intercoller piping /the knocking sounds wasn't fixed by that time yet/, new vacuum hoses, and stuff like that.

After that we've switched the manual boost controller, with electronic one, which is far better choice. We used Apexi AVC-R, black edition, which only differs from the standard one by the color. It has two channels, A and B, but actually you can use three ,because when you switch the unit off, it gives you a whole different setting. Besides, the precision of the boost control is way way better when you do it with this gauge. Especially when it comes to overboost.

Channel A, we've chose to be the weaker setting, for weak competition. We kept the setting of 1.4 bars. For better performance, we tuned channel B to get to 1.6 Bars. The overboost peaks with that setting was about 1.65 bars, which is quite accurate, but I've seen peaks as much as 1.73 /this was at the time that we've sealed a whole in the manifold and happened only once/. That's the main reason why we chose electronic boost controller. You don't need to worry too much, because it is a lot more precise than the manual one, and prevents any unpleasant overboost accidents.
We got rid of the pillar pod with all the control gauges, and instead, installed only Greddy Boost meter, which is very accurate and pretty responsive.

Got rid of the exhaust manifold too, which was welded million times by that time, and changed it for the exact same type, but made from stronger materials, twice as thick as the original ones. However, I highly recommend to stay away from log-type manifolds. We chose that one, only because that was quickest possible way to do it, but it wasn't the best choice at all. The tubular type Is the best you can get. Even at a higher price, it helps for better spool, and by far, I haven't heard anyone having problems with such thing what so ever.
We changed the rims, again 17”, but lighter than the previous ones. Wider too. Rear ones - 10J. Tires installed on the new rims were with lower profile, which set the car even closer to the ground. Finally, for exterior change, we ordered RS4 style front bumper, which was quite suitable for the intercooler and gave that Audi much more aggressive look.
Clutch that we choose to use was VR6 with G60 flywheel, which is very well known setup, and pretty reliable too. Too bad that we haven't done that earlier, because that would've save us some money from the first gearbox.

With that setup, the car actually felt quite different, in many aspects. The tires gave the feeling of better stability, and together with performance improvements, and reduce of the weight, gave us ¼ mile times around 13.1-13.2 almost at any given time, with best performance ever at 12.9. Considering that isn't Quattro equipped vehicle, it's pretty nice, having in mind that at the same strip, BMW M5 gave us 13.3-13.4.
We ended that project at that stage, due to the reason that we cannot transfer all that power to the asphalt without huge losses due to the front wheel drive. There was no actual point in trying to gain more power, and now have traction to make it efficient.
However for the car of that size and 150hp stock setting, I think we achieved enough. Actually, the most important thing was, that it gave us great pleasure and a lot of nice moments, which was the main idea. I hope that our future project will envolve more horse power, and rear or all wheel drive cars.
We enjoyed everything a lot, and look forward for more!