A4 quattro 2.8 Turbo
08-07-2007, 01:21 PM
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A4 quattro 2.8 Turbo
I'm gauging interest on who would be interested in turbo kit for this platform. I have not been able to find anyone that has done it yet, just the surpercharger setup. If this would be something people were interested in please let me know. I think that not only can it be done but car would make some great numbers. Also if I designed a kit at roughly the same price as the supercharger setup which would you rather buy!
I bought a 1998 Audi A4 2.8 Quattro, and I know that I will end up modding it. I'm a turbo guy by nature, and I have the shop and means of making this happen. I would also like this kit to be more street able than the supercharger! So let the talking begin!
I bought a 1998 Audi A4 2.8 Quattro, and I know that I will end up modding it. I'm a turbo guy by nature, and I have the shop and means of making this happen. I would also like this kit to be more street able than the supercharger! So let the talking begin!
08-07-2007, 05:10 PM
#2
you won't get any more power from a turbo then a supercharger, the 2.8 has too high compression
it can only withstand 10 psi of boost, and even that is pushing it. For a turbo to make sense you'd need to rebuild the engine with lower compression pistons. Not many people are gonna be willing to go that far.
Also, making the hardware is the easy part, getting the tuning is what makes a kit driveable and streetable. The PES kits are very streetable, unless you're willing to pony up for months of dyno and street tuning time you won't get there.
Also, making the hardware is the easy part, getting the tuning is what makes a kit driveable and streetable. The PES kits are very streetable, unless you're willing to pony up for months of dyno and street tuning time you won't get there.
08-07-2007, 08:02 PM
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Re: you won't get any more power from a turbo then a supercharger, the 2.8 has too high compression
Well everything comes down to efficiency. For example the supercharger setup is non intercooled, and the efficiency is about 55% maximum of 62%. Most Turbo setups are around 76% not to mention that island is better for staying in that efficiency range. Here is why I think a turbo setup would be better, and here is how it all works up mathamatically. First you have input valuable data such as bore, stroke, how many cyclinders. Anyways From what I have read supercharger setups max out about 11 psi. If you do the math here are the numbers. If I was at 6500rpm and 11 psi the car would make 293hp. Which this is right where PES has the numbers. Now thats at around 55%, 6500 rpm, 32C intake temp.
Now for the turbocharger setup, you now can add an intercooler also, this gives you even better efficiency, and here are those numbers. At 6500 rpm and 10 lbs of boost the car should make 337 HP. If I went single turbo I would probably do something like a to4e 50 trim.
So where does the extra power come from even though theres less boost, because the turbo has better efficiency, and being able to get a cooler air charge do to the intercooler. Which means easier on the engine, and more power.
I beleive that setup could also be more streetable is that even in cruise the car has to turn a supercharger over. Thats because it is belt driven, because of this the car generally loses some fuel economy. With a turbo it only uses wasted energy to build more power, so in cruise the engine actually has to work just a little less than normally asperated. With a turbo you also have the ability to change the amount of boost from inside the vehicle. So for every day driving you could run 5 PSI, then when you have race gas maybe get 14 psi out of that motor, and at that boost level the 2.8 A4 would make 389HP, and with a stellar tune and a awesome intercooler it might be possible to make 400Hp.
Look guys, again i'm new to the platform, though I'm always looking to try to advance the platform. Please fill free to add any comments!
added: by the way something else I would like to look into is E85 conversion. I say this cause the high compression plus a turbo would be incredible! Has anyone tried this on there vehicles, or heard of an Audi guys tryin!
Now for the turbocharger setup, you now can add an intercooler also, this gives you even better efficiency, and here are those numbers. At 6500 rpm and 10 lbs of boost the car should make 337 HP. If I went single turbo I would probably do something like a to4e 50 trim.
So where does the extra power come from even though theres less boost, because the turbo has better efficiency, and being able to get a cooler air charge do to the intercooler. Which means easier on the engine, and more power.
I beleive that setup could also be more streetable is that even in cruise the car has to turn a supercharger over. Thats because it is belt driven, because of this the car generally loses some fuel economy. With a turbo it only uses wasted energy to build more power, so in cruise the engine actually has to work just a little less than normally asperated. With a turbo you also have the ability to change the amount of boost from inside the vehicle. So for every day driving you could run 5 PSI, then when you have race gas maybe get 14 psi out of that motor, and at that boost level the 2.8 A4 would make 389HP, and with a stellar tune and a awesome intercooler it might be possible to make 400Hp.
Look guys, again i'm new to the platform, though I'm always looking to try to advance the platform. Please fill free to add any comments!
added: by the way something else I would like to look into is E85 conversion. I say this cause the high compression plus a turbo would be incredible! Has anyone tried this on there vehicles, or heard of an Audi guys tryin!
08-08-2007, 04:22 AM
#4
I ran a supercharger with an intercooler peaking at 12 psi of boost
the car dynoed at 300hp and 313ft/lbs @crank. Afterwards I melted down one of the cylinders at the track. So you can trust me when I say the 2.8 engine with stock pistons will not handle 14psi or even 12 psi safely, intercooled or not. Even guys running just 10 psi are showing signs of wear from oil analysis. These engines are just not designed to be pushed that far. I doubt you'll be able to get 337hp out of one without replacing internals, at least not without long term damage. There is only one way to get 400hp from a 2.8, and that includes new guts. I'm down this road myself with 8.5:1 pistons installed and a larger (Lysholm 1.6L) charger about to go in, stay tuned and I'll let you know how that turns out.
08-08-2007, 01:28 PM
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Re: I ran a supercharger with an intercooler peaking at 12 psi of boost
Deffently keep me posted, and please take a lot of pictures. I would love to see what the design is and stuff. Were you running race gas when your pistons blew? What pistons are you putting in the car, and what blower ar you going to use. ( I would like to see the compressor map for it.) Oh and one other thing does anybody use any injection kits!
08-08-2007, 04:27 PM
#6
I have some pics of the damage, rebuild and mockup of the new charger
on my website <a href="http://tomasz.data2net.org/gallery/album109"> here </a>.
I was running half tank of 100 octane and half take of 92 octane, so about 96 octane mixture at the time of the blowout. There was no warning signs, the piston just failed towards the end of my 3rd session. Upon inspection the pressure and extra heat of the 12 psi boost has compressed the top edge of all the pistons causing the rings to become locked up and ended up rubbing the piston against the cylinder wall until it melted.
I installed wiseco 8.5:1 pistons, there are picture in the link. The blower is a Lysholm 1600 unit, there are picture comparing it to the old eaton m62 unit and also picture of the installation mockup.
I was running half tank of 100 octane and half take of 92 octane, so about 96 octane mixture at the time of the blowout. There was no warning signs, the piston just failed towards the end of my 3rd session. Upon inspection the pressure and extra heat of the 12 psi boost has compressed the top edge of all the pistons causing the rings to become locked up and ended up rubbing the piston against the cylinder wall until it melted.
I installed wiseco 8.5:1 pistons, there are picture in the link. The blower is a Lysholm 1600 unit, there are picture comparing it to the old eaton m62 unit and also picture of the installation mockup.
08-08-2007, 08:31 PM
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Re: I have some pics of the damage, rebuild and mockup of the new charger
Seriously those pics you are takn are worth there wieght in gold! You are going to stay with stock rods and crank correct? It seems then that the only thing that is week on this car is the pistons. I very surprised that they are flat tops, not that thats a problem. I will need some time to anaylize some things to see the best way to proceed! Though I do see a lot of things we could improve on. Also I'm going to do some checking on some supercharger stuff! I want to see just how efficient I can find and how big they are, and also what kind of intercooling options there are. Keep me up to date on your install. If theres anything I can help with let me know!!!
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08-09-2007, 04:39 AM
#8
I think the major weakness in the pistons is the design of the oil rings
they are way high, causing the upper edge of the piston to be soft and crushing down under boost. If you compare to the new pistons, you can see the rings have been stepped down quite a bit to strenghten the rigidity.
<img src="http://tomasz.data2net.org/gallery-albums/album109/pistons_009.jpg">
The stock rods are the same part # as S4 rods, which the S4 guys use with big turbos, up to 400+hp without trouble, therefore I decided to keep stock. There are billet rods available for around $1200 for a set, I didn't think it was worth the expense. The crankshaft will remain stock also, the only difference here is that S4s have 4 bolt mains vs. 2 bolt mains in the 2.8. I'm not sure how much of an issue this could be, hopefully the 2 bolt mains will be sufficient.
If you want to calculate supercharger specs, there is a very useful spreadsheet here that will tell you what charger will work with the 2.8 at what boost levels and what the power output will be (theoretical at least):
<a href="http://www.sprintex.com.au/files/Blower_Calculator.xls">http://www.sprintex.com.au/files/Blower_Calculator.xls</a>
<img src="http://tomasz.data2net.org/gallery-albums/album109/pistons_009.jpg">
The stock rods are the same part # as S4 rods, which the S4 guys use with big turbos, up to 400+hp without trouble, therefore I decided to keep stock. There are billet rods available for around $1200 for a set, I didn't think it was worth the expense. The crankshaft will remain stock also, the only difference here is that S4s have 4 bolt mains vs. 2 bolt mains in the 2.8. I'm not sure how much of an issue this could be, hopefully the 2 bolt mains will be sufficient.
If you want to calculate supercharger specs, there is a very useful spreadsheet here that will tell you what charger will work with the 2.8 at what boost levels and what the power output will be (theoretical at least):
<a href="http://www.sprintex.com.au/files/Blower_Calculator.xls">http://www.sprintex.com.au/files/Blower_Calculator.xls</a>
08-09-2007, 09:33 AM
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Re: I think the major weakness in the pistons is the design of the oil rings
Yes I agree with you, though I also think that the valve relief in the piston is also a problem. I think that it is cause ing a heat spot on the piston. I think that had a big part in why your piston blew where it did! Anyways I also noticed from your pics that the stock mainfolds look extremely restrictive. Do you think it would be worth making some tube headers for this engine!