In reply to java230 :
Which Audi 4.2? 
In reply to java230 :
Which Audi 4.2?
In reply to bentwrench :
The B7 S4 specifically. 
bentwrench said:In reply to java230 :
Which Audi 4.2?
It's an ABZ 4.2, the 32v out of a 1998 A8. Not the best Audi 4.2 but it does bolt to the Porsche trans which is a huge plus. It's 300hp out of the box, hopefully it's in good shape and with a free flowing, cat-less exhaust maybe I can improve on those numbers a bit. The only big downside so far is parts and specialty tools are hard to get. I had to buy a. Upper radiator hose today and it was $250 bucks since they don't make them anymore. I'm use to Porsche BMW land were parts are still supported.
In reply to cmcgregor (Forum Supporter) :
It was a crazy sketchy setup. I must have pulled over a dozen times checking it. I need a pickup.
I need some GRM advice, the new exhaust is VERY close to the drive axle on one side. I've wrapped the exhaust but also want to wrap the drive axle boot with something. Any ideas? The only thing I can come up with is an intake wrap (below). Do you think it's hopeless and the exhaust should be redone?
In reply to Box4VIR :
Kevlar turbo blanket (CV joint). Gold film on axle. My .02's
BarryNorman said:In reply to Box4VIR :
Kevlar turbo blanket (CV joint). Gold film on axle. My .02's
A turbo blanket is a great idea, didn't think about that. Also, I just looked and damn they're pricey!
Two updates! One the motor/transmission assembly is complete and ready to install. Also more importantly I'm now a dad! So work on the car has stopped and my only automotive outlet now is researching a build for the second Audi ABZ motor. The advantage of the ABZ V8 is its very compact (90mm) bore spacing. This tight spacing makes it easy to fit into mid engine cars but makes it hard to fit an efficient intake or header design. The build below for example was able to go from 295 crank hp to315 wheel horse power just by changing the intake manifold and exhaust manifold. There really isn't an off the shelf solution but I could, maybe, make Audi R8 parts work... hear me out. The Audi R8 also has a 4.2l V8 with 90 bore spacing but is a completely different design. The intake manifold pattern looks the same as my ABZ engine and the ABZ engine doesn't have a coolant passage in the manifold which helps. The biggest hurtle I see is the lack of fuel injector ports in the R8 manifold. Like the R8 this would sit in the rear window of the Boxster. What do you guys think is it worth trying to make one of these work? They're fairly easy to come by on eBay surprisingly. Maybe the lack of sleep is finally catching up to me...
That looks GOOD! I would absolutely say you should do it.
Well I've also had some enormous scope creep. I decided that lifting the car 2 feet off the ground to pull the engine from below is absurd and I don't have enough faith that I can service the Audi V8 with the factory engine cover in place so I did some cutting... I removed he entire engine surround and fire wall, rear trunk and moved all the electronics to the cabin I'll make an aluminum firewall that goes all the way to the roof and will either install a plexi window or install a hidefinition rear camera that uses the a rear view mirror as a screen (oddly the cheaper option). With the rear trunk removed I can now just wheel a new motor in instead of lifting the car up and pulling it from underneath (especially valuable with the tall V8 compared to the flat 6)
you can see in the above photo I'll need to add some rear chassis reinforcement, I'm going wait for the engine to go in and then tie something into the cage to strengthen it The solid mounted engine and trans would probably provide enough strength on their own, but I won't count on it.
another nice little perk is I've removed more metal weight than the V8 is adding (in NA form...which brings me to the next topic)
While I was at it I decided to solve my exhaust routing problem above. There just isn't room below the motor so the only option is go up and why not add some turbos too...these engines are great foundations for turbo builds. People frequently run 800+hp without opening the case and actually the record for the highest hp (stock internals) Audi engine is held by a single turbo top fuel dragster using the same Audi 4.2l ABZ with 1600hp out of a junkyard motor. Wild stuff! I'm going to install two top mounted Borg Warner S200SX-E turbos and run 12psi of boost for 525hp (based on the volumetric efficiency of the engine and its other specifications). The turbos are still efficient with this engine to 800+hp if I ever want to blow it up which at $200/engine I just might decide to do. I already have a spare after all.
I've seen enough turbo track car builds to know this is a mistake and that my only chance is crazy amounts of cooling so I have a huge 3' long dual core water to air intercooler with two side mounted intercooler radiators in the widebody fenders (hopefully they'll get enough airflow). I went with the water to air intercooler to allow me to use a massively oversized cooler without the pressure drop and lag of an oversized air to air intercooler. It also will supply a much more consistent intake temp which hopefully helps with tuning. Finally it allows me to eliminate virtually all of the charge pipes and since it'll sit, hard mounted to the top of the engine I think I can get away with using only v-bands (no rubber boots boots to split, fall off, etc). A normal intercooler piping setup has to deal with engine movements in relation to the chassis which this setup won't have
I've also added a large aluminum radiator in the what used to be the frunk that vents out of the hood vents I added, I'm keeping the factory radiators as well. I'm still chewing on the turbo and engine oil, cooler I've removed the factory water/air cooler on the side of the motor, drilled out the ports and added AN fittings which I'll run to the accusump and some type of cooler. Since I have such large radiators on my air-water intercooler radiators I'm tempted to install two water to oil coolers for the turbo and engine and plumb them into the intercooler rads Not sure yet.
Fortunately my fab guy will handle the turbo fab work and I'm going to outsource the wiring. I'm going to focus on getting the cooling in place, fortunately with the air-water cooler approach I only need to run AN lines.
the transmission is a question mark, it probably won't hold up to the power with the 315 Hoosiers I have so I'll have to install a Boxster S transmission at some point (soon). Maybe a cooler would help. I really don't want to drop 2k on one now though
here's a shot of the engine that was ready to go in. To make the top turbo mount work I flipped the exhaust manifolds (which took about 2 hours of oil dip stick rebending to make work) and flipped the exhaust that I had made for the NA build, I think I can use of the down pipe. The turbos will wit right behind and above the engine and will feed directly into the dual inlet air/water intercooler that sits on top of the engine (not the best location but it eliminates virtually all the piping and makes the engine a unit I can slide right in once it gets back from my fab guy)
Does anyone have any info on air to water intercooler radiator sizing? All the articles I can find say go as big as you can which doesn't do anything for me.
Parts have started trickling in for the turbo build. I test fitted one of the water to air intercooler radiators (which is really heavy, probably around 20lbs) and based on its weight I'm really hesitant to add another one. Once it's full of water each of these will probably be 40lbs. The original plan was to tuck one into each fender flare (shown in the pic) but now I'm thinking of using one of them for an oil cooler which I still don't have a good place for. I'm targeting 550hp for the initial tune, do you all think the car would benefit from two air to water intercooler rads (based on their not ideal location)? They're 26.5x7"s each. The intercooler itself is a huge dual core 31x14" unit. I'm going to add a methenol spray kit which will lower intake temps too. Also in the first pic you can see the door is in the way, I'm going to cut the door just below the handle and down to the door sill (horizontally to the front of the door) and then fold the door skin back to the inside of the door frame to add additional air flow. I really need a water to air intercooler sizing formula but everything just says "as big as you can make it" which is probably a very relevant statement for a front engine car with very little space to play with. Speaking of the front of the car I'd move the cooler to the front but I have three radiators up there taking up 100% of the space
Intercooler rad fits in this fender opening (not ideal) but based on the huge top speed drop I had after installing these fenders I'm assuming it's getting plenty of air.
the back of the fender is also vented to let the air escape (nice side effect to not being able to bend aluminum in two dimensions with the tools I have).
among the parts trickling in are the injectors, I really hated spending the money on these but man are they nice! Machined bodies and all, it's too bad they'll be covered. At least I can show them off here.
the motor is finally in! The fabricated engine cradle bolted right up which is a huge relief. I also got the engine oil circuit in, anyone know if an accusump will mind being bolted up to a transmission?
Slowly making some progress, the coolant system has been a nightmare. I've bought countless hoses, fittings and aluminum pipes. The second picture down is just a portion of the hoses that have gone into this. Getting the high Audi coolant lines all the way down to the bottom and middle of the chassis so they can run forward has been a challenge. The Boxster also has two radiators from the factory but I'm running three with one large one in the middle so I had to reroute the lines for equal flow (the standard 3rd S rad has very small lines running to it so I didn't want to use that setup (probably should of though)). I also just placed the order for all the Turbo goodies :) I settled on two Borg Warner S200SX-E turbos which I'll run at 12psi which should net about 520hp ( I would have loved to get EFI turbos but couldn't justify spending that kind of money). I have a plan for a water cooled intercooler setup good for 2,000hp just to make sure I can keep the temps down, more on this later. The next challenge is the throttle cable, any advice on making a longer throttle cable? There seems to be a lot of kits out there, any advice?
How it sits today...long way to go
The good news is the turbos arrived, the bad news is they shipped the wrong turbos... This may not be a horrible thing because it gives me an opportunity to spend even more money and get a single EFR turbo in place of the twin S200SX-E turbos that I ordered previously. Below is a comparison of the options (all low boost), if you have any feedback or advice please let me know. This is my first turbo adventure.
I'm also thinking of changing up the Turbo install location. My original plan was the first image below, but now that I'm feeling the weight of these things I'm thinking about going with option three to lower the weight as much as possible. Any thoughts?
I've also been playing with realdash which will replace my factory cluster. I designed some gauges that fit behind my factory cluster, the tablet will tuck completely behind the dash. This is going to be powered by a VEMs unit the EFI Express is making for me (I returned the Megasquirt). The VEMs unit is going to bench tuned to the turbo selection, injectors, etc and they're modifying my hardness to be totally plug and play. Huge win..this will take hours off the build hopefully
Video of the gauge in action
https://youtu.be/xPJ0kvIynyk
The turbos are bolted on for test fitment, everything seems to fit well the turbos just tuck under the trunk lid at the same angle of the lid. The next big challenge is the charge piping and intercooler design. I'm using an air to water intercooler which I'm planning on placing on top of the intake manifold but I don't have a great idea yet on how to gracefully connect the two turbos. If anyone has seen a setup that they think I could copy let me know
It'll probably be another year before my current project is done but of course I'm already thinking about what I can spend my time and money on next. The transmission I'm installing is an audi unit that has the same output shafts as the Boxster on the side of the transmission but it also has a conventional output shaft in the back to power the rear wheels on the audi (on the boxster I don't need this output shaft so it just will hang out under the rear bumper. To make this transmission work on the Boxster the center diff in the transmission has to be welded together this will mean the rear output shaft spins when the wheels are spinning. My idea is to put a pulley on it and use a belt to power two large engine mechanical fans that will "charge" a diffuser on each side of the transmission. Kinda of a sucker-car-light design that doesn't require the car to be sealed to the ground. The good news is that the transmission output shaft is in the perfect location, so I could just bolt a pulley directly to it which makes this much simpler. I am not a fluid dynamics guys but google tells me that a 2"x20" diffuser opening will see around 2,000CFMs at 80mph, and a 12" mechanical engine fan can generate 5,000+CFM so very rough math it looks like a 12" fan could accelerate the air going through a diffuser. The fan speed will be limited to the car's speed so thats a problem but I could play with the pulley sizing to "tune" the speed to be ideal around 100mph. Sealing the fans to the diffusers so no air can escape could be tough but certainly easier than sealing the entire underside of the car
Over the weekend I installed the first of two water to air intercooler radiators into the rear fenders. There was a tremendous amount of cutting and test fitting to get this in, its absolutely crammed in there. I still need to make some aluminum pieces to seal up the doors and cover the bottom gap in the fender but I'm really happy with it so far.
Some Testarossa style fins make help channel the air in there
This is Unhinged. I love this thing. Keep up the Insanity.
On the "Acitve Aero" front. First Make sure it would be legal before you go through all the effort. Physically tied to the wheels seems like a reasonable way to go. Yes the Aero effect will increase with speed but so does the effects of actual Aero so that doesn't seem like the end of the world. Make an Estimate of what kind of HP it's going to take to drive the fans. Your Engine will obviously produce enough of it, but if it's driven by the transmission output shaft it will be tied to the rear wheels. So whenever you push in the clutch for braking that will be increased load on the rear wheels. I'm not sure how much it will be but it could unbalance the car and will likely require some strange brake bias adjustment to keep from locking the rears.
Look into the Gordon Murray T-50 for the kind of Aero your talking about. His new car is going to have a big fan on the back but not sealed skirts, it will function like how you are discussing. There are some good videos on youtube where he discusses the function an throws around some HP numbers and PSI changes.
In reply to Placemotorsports :
I was thinking about it, I can't figure out if they're functional or not. I'm not excited about the fake kit car look it would have but it'll help I'll do it.
nocones said:This is Unhinged. I love this thing. Keep up the Insanity.
On the "Acitve Aero" front. First Make sure it would be legal before you go through all the effort. Physically tied to the wheels seems like a reasonable way to go. Yes the Aero effect will increase with speed but so does the effects of actual Aero so that doesn't seem like the end of the world. Make an Estimate of what kind of HP it's going to take to drive the fans. Your Engine will obviously produce enough of it, but if it's driven by the transmission output shaft it will be tied to the rear wheels. So whenever you push in the clutch for braking that will be increased load on the rear wheels. I'm not sure how much it will be but it could unbalance the car and will likely require some strange brake bias adjustment to keep from locking the rears.
Look into the Gordon Murray T-50 for the kind of Aero your talking about. His new car is going to have a big fan on the back but not sealed skirts, it will function like how you are discussing. There are some good videos on youtube where he discusses the function an throws around some HP numbers and PSI changes.
Thanks! I didn't think about off throttle drag on the rear wheels, great point. I'll have to chew on that one. the fans I've picked out are diesel engine mechanical fans, the whole assembly will require around 20hp from what I can tell which is significant but the car will have 750hp (or close too it) so I'm not overly concerned. Since I'm using mechanical engine cooling fans with v-belts I was thinking about connecting an AC clutch to the drive pulley so I could turn the system on and off this would come in handy on straight always if I'm really trying to push it. As far as the legality of this its a UTCC build where everything is legal.
I just looked up the Gordon Murray T-50, thanks for passing that along. They're using a 12hp electric motor so it sounds like I should have enough CFMs in my design.
Few thoughts:
Electric or other clutch on the pulley that drives the aero fans to decouple them under braking?
Lotsa stuff crammed back there. Any value to splitting the feed air to the fans between venting the engine bay and the aero?
Why not rotate the turbos so that the turbine exhaust exits face to the rear?
bluej (Forum Supporter) said:Few thoughts:
Electric or other clutch on the pulley that drives the aero fans to decouple them under braking?
Lotsa stuff crammed back there. Any value to splitting the feed air to the fans between venting the engine bay and the aero?
Why not rotate the turbos so that the turbine exhaust exits face to the rear?
I was thinking about using an AC magentic clutch to turn off the fans which would work for initial braking sometimes but I'd want to make sure its on when I'm trail braking. Its a complicated problem.
The turbos are pointed that way to allow the exhaust to point just below the wing (exhaust currently being fab'ed), I'm trying to use the exhaust to increase flow under the wing to increase it's efficiency which is a well known trick. but yes I agree it would have been much easier to spin the turbos around, I wrestled with this one for awhile. The downside is that the exhaust turns 180 degrees but it sounds like this isn't actually a bad thing as the turn helps convert the rotational velocity of the exhaust coming out of the turbine to a linear velocity. We'll see... Turbos are totally new to me, and there's a ton of bad information out there.
Here's the exhaust plan, amazing engineering drawing quality I know... Also, I'm a little worried about catching the carbon wing on fire. I might need to swap it for an aluminum one or maybe some heat reflecting tape will work
As for engine bay venting I'm pulling air in through the side fender vents and am replacing the rear lexan window with a mesh grill material so it should be well vented. the trunk lid is also going to be vented so the turbo heat can escape. I still have no idea where to place the oil cooler
minor update: I finally got the inter cooler in and mocked but I'm afraid it's a little small for 750hp and the odd oval throttle body (oval with two different diameter sides of the oval) is a little sketchy. I really didn't want to change out the throttle body but I think I'm going to have too, as is I don't think the silicon boot is going to stay on under boost. On a positive note I was able to get some of the aluminum panel work done on the door, I still have some more to make to seal up the intercooler and door completely but the plan looks like it'll work
Absolutely love this build. I wonder if a more effective fan could be found than stamped steel radiator fans. Maybe a helicopter compressor inlet or something?
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