01 Audi TT225 compound turbo setup

[Audiguy84]

except preventing your front end from spitting like a banana, also don't you think it would be easier to fab up the turbo kit with the engine out of the car?

[Dowski12]

Normally yes but becuase of where the turbos will be sitting and where the pipes are running there is going to be a very limited amount of space to fit everything. Doing it with the motor in will let us know where we can run the hot exaust pipes without melting anything. It also is giving us a good Idea of where we are going to have to re-route alot of the hoses and what not. Without even having the turbos in yet we can already tell we're gonna have to move the heater core hoses so even though the fab work will be alittle harder with the motor in, it gives us a good picture of where everything is being layed out.

I'm certainly not the first person to remove the crash bar, I think it will be ok, if not I guess I will have two sides to a really fast car

[Dowski12]

Intercooler is mounted, we're just waiting on the stainless piping to get here.

The dirtiest my car has ever been




Used the crash bar mounts and some metal stock we had laying around, worked out pretty good. Definitley needs to be cleaned up though.


Also, ordered Maestro today, hopefully gets here before the fab is complete. Will keep you posted

[warranty225cpe]

Removing the crash bar is a bad idea. If you get in an accident and the insurance adjuster sees that, you can almost guarantee your claim being dropped. Treadstone tr8 fits right behind the crash bar

[Marcus_Aurelius]

Removing the crash bar is a bad idea. If you get in an accident and the insurance adjuster sees that, you can almost guarantee your claim being dropped. Treadstone tr8 fits right behind the crash bar

Not only that, you are loosing tons of front end rigidity. With the cross IC pipe removed and no crash bar, there is not much left to brace the two front frame rails. Personally, I'd look for a solution to bring back some structural rigidity to the flexy flex front end.

BTW OP, the radiator is not going to love the airflow available to it now, especially with the possible heat hike generated by the compound setup.

[20v master]

Not only that, you are loosing tons of front end rigidity. With the cross IC pipe removed and no crash bar, there is not much left to brace the two front frame rails. Personally, I'd look for a solution to bring back some structural rigidity to the flexy flex front end.

Not to doubt your experience and knowledge, but I think you exaggerate here a bit. There is the front strut bar as well as that large lump known as the engine/trans. Now if your side motor mounts are old and soft, then you're losing some there, but if you have VF mounts or other stiffer solutions on the market, then the engine itself is quite a brace. That said, the forces in the frame rail come from the suspension mounting points, meaning the strut towers and subframe mounting points are where forces enter the chassis. While deflection may be at the highest distances way out on the front of the frame rails, the forces causing that is far away from it. Have you added any bracing to your subframe at all or gone to solid subframe bushing/mounts (not sure if that's allowed in your class)?

[Dowski12]

Havent changed bushings or anything yet. Ill have to check cause im not sure if its allowed in my class either. I did talk to JC about mounting a brace between the crash bar mounts behind the intercooler. He seems to think it should be fine without the crash bar since he runs 1400hp cars without them and they dont seem to be splitting in half, but he said he would do whatever I want him to, I'm not really that worried about it though. On the street I dont really ever drive that crazy and on the track, wrecking the car with or without a crash bar wont make much difference as far as saving the car when your going 100+mph. I dont understand why everyone seems to think the crash bar is meant to hold the car together. If that was the case I imagine it would be a hell of lot thicker/stronger material.

The TR8 is too small for my HP goals. Later on im looking to swap turbos and see how far I can really push this setup.

[Marcus_Aurelius]

Not to doubt your experience and knowledge, but I think you exaggerate here a bit. There is the front strut bar as well as that large lump known as the engine/trans. Now if your side motor mounts are old and soft, then you're losing some there, but if you have VF mounts or other stiffer solutions on the market, then the engine itself is quite a brace. That said, the forces in the frame rail come from the suspension mounting points, meaning the strut towers and subframe mounting points are where forces enter the chassis. While deflection may be at the highest distances way out on the front of the frame rails, the forces causing that is far away from it. Have you added any bracing to your subframe at all or gone to solid subframe bushing/mounts (not sure if that's allowed in your class)?

Adam, I hear what you're saying. I'm concerned about the 5th spring. There is quite a bit of dynamic unibody flex with steering angle and also with elevation variance of the road surface (think entering a driveway at an angle). It is a known fact that unibodies flex a lot, but how much does ours deflect with load? From what I can see, there is quite a bit of flex. Anyone can try the following to understand what I'm concerned about:

- Jack one of the front tires off the ground and check the door alignment/gap

- Put the car on a lift and look or measure the front end sagging from its own weight (no loads).

- Tie the two shock towers with a string (there can be a little slack) and go for a few spirited turns in both directions. The fifth spring/flex will take care of over extending the string with ease, even with the little slack, it will be broken after a few spirited turns.

To answer your question about bracing, I can't triangulate anything in my class but I've tied 2 single points in a few locations to help the chassis. Remember, I already have the second most rigid frame in the line up (3.2 coupe being the most rigid) and Audi already gave me a lot more to work with because of the additional factory frame bracing and OEM solid frame mounts . It may not mean much to the OP, and having extra dynamic toe, camber, and caster movement maybe low in the priority list but it's there (especially when you drop 75% of what tied the rail on the steering end together).

[Dowski12]

Marcus, do you have any suggestions for making the front in more rigid? (besides using the crash bar that is)

[20v master]

To answer your question about bracing, I can't triangulate anything in my class but I've tied 2 single points in a few locations to help the chassis. Remember, I already have the second most rigid frame in the line up (3.2 coupe being the most rigid) and Audi already gave me a lot more to work with because of the additional factory frame bracing and OEM solid frame mounts . It may not mean much to the OP, and having extra dynamic toe, camber, and caster movement maybe low in the priority list but it's there (especially when you drop 75% of what tied the rail on the steering end together).

I'm aware there is a lot of chassis flex. Like you said, you can tell when the car is jacked up by how the doors close and line up. That said, my point was to brace where the forces are, not where the greatest effect is seen. How is the 3.2 coupe more rigid than a 1.8 coupe though, other than the engine and giant DSG? Is the subframe different? I wasn't aware of any differences other than the rear floor pan. What are OEM solid frame mounts you mention? Educate me please.

[Charlie_M]

I'm aware there is a lot of chassis flex. Like you said, you can tell when the car is jacked up by how the doors close and line up. That said, my point was to brace where the forces are, not where the greatest effect is seen.

A big part of the strut tower deflection is torsional, aka twisting. Both the crash bar and the SMIC connecting pipe do a lot to prevent the front frame rails from twisting, and combined, they are even better. It's not (just) about keeping the frame rails spaced apart the right distance.

How is the 3.2 coupe more rigid than a 1.8 coupe though, other than the engine and giant DSG? Is the subframe different? I wasn't aware of any differences other than the rear floor pan. What are OEM solid frame mounts you mention? Educate me please.

Not sure about the 3.2, but the convertible has additional subframe bracing to make up for the reduced torsional rigidity due to losing the roof. I think even with uprated mounts, you can't count on much reinforcing from the engine & tranny.

Also, if you keep your FMIC setup like the pictures, you might want to add a little flexibility to the mounting; otherwise you could end up trying to use the FMIC as a brace, which would likely crack at some point.

[Marcus_Aurelius]

I'm aware there is a lot of chassis flex. Like you said, you can tell when the car is jacked up by how the doors close and line up. That said, my point was to brace where the forces are, not where the greatest effect is seen. How is the 3.2 coupe more rigid than a 1.8 coupe though, other than the engine and giant DSG? Is the subframe different? I wasn't aware of any differences other than the rear floor pan. What are OEM solid frame mounts you mention? Educate me please.

You guessed it right, the 3.2 is the only coupe with the Roadster subframe. The roadster subframe reinforced the front end by 30% to make up for the 15% lost over the coupes. The Rodster frame mounts are also solid two pieces items (delrin I believe). All the Mk4 golf guys that road race upgrade to TT roadster frame mounts and replicate the extra bracing of the roadster subframe. According to them it totally transform their cars and can see it having the same effect on a regular coupe also (no exaggeration when I warn against removing even more front end rigidity by removing the cross pipe and crash bar).

Roadster/3.2 subframe where you can see the OEM bracing and solid mounts
[/B] [B]


Cross bar that I added to improve on the extra OEM roadster bracing

[Marcus_Aurelius]

A big part of the strut tower deflection is torsional, aka twisting. Both the crash bar and the SMIC connecting pipe do a lot to prevent the front frame rails from twisting, and combined, they are even better. It's not (just) about keeping the frame rails spaced apart the right distance.

Not sure about the 3.2, but the convertible has additional subframe bracing to make up for the reduced torsional rigidity due to losing the roof. I think even with uprated mounts, you can't count on much reinforcing from the engine & tranny.

Also, if you keep your FMIC setup like the pictures, you might want to add a little flexibility to the mounting; otherwise you could end up trying to use the FMIC as a brace, which would likely crack at some point.

Charlie, we seem to be on the same wave length on this. I thought the same thing when I saw the FMIC mounts. I didn't say anything because I figured tha it would Just break the welded stud (intercooler side) when subjected to chassis flex. Are you an engineer by any chance?

[Dowski12]

Well I guess I know what I'm doing after my build is done. Im ordering my coilovers and brembos next month so I guess Ill be getting a roadster subframe at the same time. Thanks for the info. I wasen't aware there was any difference in subframe design.

Marcus, is the roadster subframe a direct fit or is there any modification involve?

As far as my intercooler mounts, the metal stock we used flexs pretty good. JC said that the mounts would have to be able to flex for the same reason you mentioned so hopefully I should be good there.

[Charlie_M]

Roadster/3.2 subframe where you can see the OEM bracing and solid mounts

And you can see unauthorized roll center correction and caster increase

Cross bar that I added to improve on the extra OEM roadster bracing

You might not be allowed to add triangulating bracing, but that's a pretty convenient & effective triangle you generated with one straight brace.

[Charlie_M]

Are you an engineer by any chance?

Yeah, but don't hold that against me ...

[Marcus_Aurelius]

And you can see unauthorized roll center correction and caster increase

Yes, for caster and camber increase trough my custom ball joint relocating plates. I purposely didn't elongate the ball joint pivot to mounting point distance to relocate the roll center and keep it legal in my SCCA class. You have amazingly good eyes (although you missed the elongated swaybar arms that effectively reduce the bar's rate.

You might not be allowed to add triangulating bracing, but that's a pretty convenient & effective triangle you generated with one straight brace.

Yeah, the roadster existing factory braces made it hard to pass on the opportunity.

Yeah, but don't hold that against me ...

Definitely will!

[Marcus_Aurelius]

Marcus, is the roadster subframe a direct fit or is there any modification involve?

As far as my intercooler mounts, the metal stock we used flexs pretty good. JC said that the mounts would have to be able to flex for the same reason you mentioned so hopefully I should be good there.

The subframes are interchangeable between the models without modification. I would suggest that you sandwich some rubber grommets or something in between the welded IC bolts and frame brackets. It would make it much more durable to chassis flex.

[Dowski12]

Ok, I got plenty of extra rubber grommets so Im sure I have some that will work. Thanks for the help. There is a guy selling his subframe and control arms from his 05 3.2 for $325 shipped. My question is, do I need his control arms or can I just get the subframe and use my own? Also is there any benefit to swapping to his control arms? And finally is this a good price for everything?

[Marcus_Aurelius]

Ok, I got plenty of extra rubber grommets so Im sure I have some that will work. Thanks for the help. There is a guy selling his subframe and control arms from his 05 3.2 for $325 shipped. My question is, do I need his control arms or can I just get the subframe and use my own? Also is there any benefit to swapping to his control arms? And finally is this a good price for everything?

Nope, no need to get his control arms. They are all the same (except for the unicorn pre-recall "MK1 ones) and your arms will bolt to his subframe. As far as pricing, $325 seems fair although I've seen them go for dirt cheap. BTW while you have it out, before swapping the subframes, I'd weld the two round ears on the frame (the ones that house the rearward mounting bushings) to the diagonal roadster braces. It is worth the trouble, although I have not done it to my car due to classing restrictions.

[Dowski12]

Ok thanks for the advice. I think Ill take a look at my class restrictions before I weld anything though.

[Dowski12]

Got some goodies in the mail today. Nothing can stop me now!!!

Stainless Pipes for my intercooler


Podi Boost Gauge (my current one only went to 20psi)

[warranty225cpe]

Wait..., your class allows you to run 2 turbos but you CAN'T add extra chassis support?

[20v master]

And is it just the angle or does the gauge read less than zero with nothing hooked to it?

[Marcus_Aurelius]

And is it just the angle or does the gauge read less than zero with nothing hooked to it?

I've seen that happen with many mechanical pressure gauges (usually Autometer). They can be fixed/calibrated to sit in the zero box but I'm not sure what that does to the accuracy of the gauge.

[Luis92]

but I'm not sure what that does to the accuracy of the gauge.

it will take boost to get to "0" wich will mean "NO boost"

[20v master]

I've seen that happen with many mechanical pressure gauges (usually Autometer). They can be fixed/calibrated to sit in the zero box but I'm not sure what that does to the accuracy of the gauge.

Yeah, I like having my Zeitronix wideband with the ability to calibrate the boost sensor to compare to my analog gauge. I just started a new job and moved recently, and decided that my stroker/35R setup is going in my black TT, along with the gauge setup. The GTI will have to make do with rods and a 2871.

[cincyTT]

Should of got a tr8 or a tr12. Said it a few times that the tr10 is to wide for the crash bar. Much smarter to run the crash bar.

[Dowski12]

I agree, would be smarter but theres no turning back now Definitely gonna add some support though to make the car more rigid at least. Buying a 3.2L subframe from a guy on here, hes sending it on friday so that will help. JC is going to weld a support between the crash bar mounts too, probably out of some nice thick round stock he has at the shop. It wont do much to save the intercooler but hopefully it will help protect everything behind.

[Dowski12]

It is sitting below zero, not sure if its supposed to be like that but we'll see what happens when its hooked up. If its a problem ill swap it for a new one.

[Dowski12]

JC sent me photos of the 60-1 after powder coat.

[snow_muncher]

Awesome stuff

I'm currently on a GT2860RS, but want more power AND faster spool

Not prepared to suffer a laggy single big turbo though

[Dowski12]

Update: Cold side intercooler piping is welded up and polished, turned out really nice. Hot side is half finished but we are waiting on silicone couplers to show up, should be here tomorrow. Both turbos are back from powder coat and welding, and both look amazing!!! Now on top of all that we are changing the layout of my setup. Instead of one being behind the motor on the manifold and one mounted on the driver side, we've decided to make a custom header to wrap around the motor and have both turbos on the drivers side (sitting side by side). After we mocked up everything with both turbos in the car, I can tell you this is definitely the way to go. Shortens up my piping quite a bit. Not to mention its going to look sick when you open the hood to find 2 turbos staring you right in the face. I will have pictures later. Went over today with my carmera but as soon as I tried to click the first pic, the batteries died. Stay tuned.

Oh also I recieved my maestro 7 tuning suite in the mail yesterday, and bought a 3.2 subframe off of a guy on vortex. Should be here Thurs

[Dowski12]

Sorry guys, been a while since I updated. Things have been crazy busy so I hadn't gotten a chance to get over to the shop and take pics. Just a few updates...

Cold side Pipe finshished and looking pretty, tight fit under the headlight






Started my header yesterday, looking pretty rough right now



The header should be tacked up today, I'll go and get more pics later...stay tuned

[Dowski12]

Also bought a Sigma 6 short shifter today. Got to lookin at the pictures I posted and all I could see was metled plastic when I looked at the shift linkages