Eric's V8 CQ

[cuatrokoop]

Looks Great!

I had considered relocating the fans into pushers rather than pullers and scooting the radiator back a bit. That would let you not cut headlights.

I'm glad you found a good solution for the turnbuckle!

I may swap them around, I dunno, the hoses are pretty tight as it is... But yes, I'm hoping the gas spring is the be-all, end-all solution!

[90quattrocoupe]

If you are going to go with pushers, don't use Spal. Not enough cfm. Get a couple of A4 HVAC fans. They put out a lot of air.

Greg W.

[cuatrokoop]

I may try to get thinner puller fans. The fans Ben installed move enough air but clearance is tight everywhere up front (as I'm sure you are aware, Greg!). I've looked at Derale among others.

[cuatrokoop]

Update on the gas spring install; even in cold weather I have not had an issue. Including some pretty high engine rpm rips in cold weather.

Starting is still hard, I need to pull fuel or change enrichment, or something but am so unfamiliar with VEMS I'm not sure where to begin. Unless I get the throttle position just right, I am greeted with a giant cloud of fuel stink smoke. Warm or cold ambient temps, warm or cold engine, doesn't matter. Starting is a problem. I did manage to help it out with a Group 90-something battery which has something like 1000CCA.

I'm also looking at offset upper strut mounts to gain more caster, which would be good for suspension geometry and autocrossing. I am fairly certain I will be ordering them from a site in Poland, I've talked with the company owner a little bit, looks like delivery will only take a little over a week. Price seems fair as well. Only thing I need an answer on, is if I can run the B4 strut tower brace brackets (the weld-on pieces) with his USM's. I have brand new, never installed brackets and the square tube sitting, but I can't tell if they'd fit together.

So, I'm waiting on warmer weather to do more work, since my garage is not fully insulated and I don't have the heater installed yet...

[cuatrokoop]

Also, I think I'm going to cut out most of the area in the S2 bumper license plate recess, and add in some black painted mesh to allow more air to hit the radiator.

[Grillage]

Glad to hear you conquered the alternator belt!

Are you having overheating issues with the new bumper or are you just making sure you don't?

[cuatrokoop]

No, no over-heating issues, however I haven't run it really hard in the summer. I just don't want to have an issue during an auto-x in the paddock area (also why I need to fix the starting issues, since it sits for a bit shut down then you have to hurry-up and get moving now!). I'll trailer it to/fro, so I won't have the added heat from driving it to events on hot days. I think I am also going to space the back of the hood to allow air to escape the engine bay easier with out having to cut the hood for vents.

Yes, I really think the gas spring is the ticket to these things when not using the full factory tensioner. I do think that this, with the fans and PS pump, needs a larger alternator (or maybe the VREG replaced, which I have one somewhere in my stash).

[AudiSport4000]

Gimme a shout when it gets warmer out. I'd love to see this thing and help ya wrench.

[cuatrokoop]

Will do, Mike!

[90quattrocoupe]

Instead of cutting out the license plate area for more air flow to the radiator, try making a sheet metal scoop to direct air from the lower center grill up toward the radiator. This way the air does not just pass underneath the radiator . You can also fabricate some type of seal between the hood and top of the radiator. This will prevent air flow from going over the top of the radiator.

I built ducting so that all the air coming in from the hood grill and lower grill, is forced through the radiator. I installed ducting on both sides of the radiator also.

Greg W.

[cuatrokoop]

Greg, I'm sure I've seen photos in the past, but how do you help get the air out of the engine bay? Not sure I want to add a bunch of ducting, as I like being able to actually access the FEAD

Also, I have a set of brand spankin' new castor increasing upper strut mounts sitting, waiting for this Ohio winter to decide if it is winter, or spring. They'll go in along with the reassembled struts with new spring rates (and new springs, since T.C. didn't know how to assemble a suspension properly from the looks of it). I contemplated running offset subframe bushings as well, but for one they are aluminum, and two I didn't know if there was enough slot length in the transmission mounts to make up the difference. Depending on how the wheel sits in the arch, I may have to run them and just deal with the added harshness (they aren't that expensive). May also just go all in and swap to more track oriented engine and transmission mounts at that point. We'll see.

[90quattrocoupe]

Not really any pictures of my current setup, as far as the radiator goes. Didn't think about pictures, when deciding how I wanted to go and was pressed for time before a track event.

I originally had 034 do my engine installation, because I haven't done any welding in 50 years and I was going with 034 IIC for control. I don't do electronics very well. The original radiator they installed, was not adequate for the job. So I had a copper/brass end tank radiator made to the dimensions of the B4 radiator. I had them peel the top mount strip piece off the top of a B4 radiator and install the lower mounts from the B4 radiator to the one they made of me. This way I would have a radiator that mounted in the stock location. By using the top mounting piece from the B4 radiator, I was able to use the top seal for between the hood and the radiator.

My radiator has the return water from the heads, going to a driver's side inlet at the top of the radiator. A lower side outlet feeds the water intake at the thermostat housing. Even though the original B4 radiator is a single row radiator, they fitted a dual core in mine, with about the same depth as the top mount from the B4 radiator. My radiator is a triple pass so it goes from the inlet on the driver's side to the passenger side, then back to driver's side and back to passenger side outlet.

I am using a Spal fan behind the radiator on the driver's side and two A4 AC fans in front. The A4 AC fan on the passenger side and the Spal fan come on a about 90 degrees C, and the driver's side AC fan is controlled from the AC switch on the climate control. One thing you have to watch out for with Spal fans, is they like to give the velocity in CCMs instead of CFMs. Cubic centimeters per minute are lower than cubic feet per minute, so the number sounds high in CCMs but comes out about 3/5ths the number in CFMS.

My setup has been tested at the track and in 95+ degree weather in bumper to bumper traffic and no overheating. My biggest problem is at night. I can be cruising down the freeway and I get too much cooling. I have a tendency to go through thermostats. At night the water temp will come up the thermostat will open, the cooler water will flow and within a couple of minutes the thermostat closes again, because the motor cools off to below the thermostat temp. At the times when my thermostat is broken and wide open, when cruising on the freeway, the temp will not even reach the first dot on the gauge. It runs too cold.

I don't think vents in the hood will do you a lot of good, unless you have something like on a Lancer EVO , with the hood vent right behind the radiator. The problem with the radiator right in front of the V8, is the flat wall the air hits after it goes through the radiator. I call it bounce back. The faster you go the more air flow bounce back. The hood vent just behind the radiator will create a low pressure area behind the vent, because of the air flow over the hood, so it might help. One of the problems with, a vent in the hood, just behind the radiator, is the radiator hoses. They will be blocking any air flow upward. The Naca ducts in the B4 belly pan create a low pressure area for air flow under the engine. They will help under the hood air also. The engine is a V8 so there will be more air flow at the lower portions of the motor vs the wider upper part of the motor. Not only that, but with the air box on the passenger side and the stuff on the driver's side, rear or side hood vents are I personally, don't think, are going to help a lot. Are you running a belly pan? B4 is better than the B3/coupe ones.

I will be doing my thermostat in the next month, so I can get more pictures, but here is a couple showing my ducting and front fans. In the first picture you can see the how the radiator is mounted using the original B4 mounts and the hood seal.



In this picture, you can see the fans and the ducting on the sides for the radiator.



Hard to see, but here you can see the lower duct directing air to the radiator. It is white behind the grill. The black running across the white is wiring for the passenger side headlights, turns, etc. The side duct guides extend all the way down to this lower duct scoop.



Click on the pictures, they will get larger.
Greg W.

[cuatrokoop]

Thank you for all of that, Greg, greatly appreciated. I do not have a belly pan, I couldn't get one to fit with the S2 bumper on my old CQ, at least not well. I did find on my old C5-A6q that the belly pan really helped oil temps. Maybe when I get all the rest of the stuff taken care of I'll fab up an aluminum pan at work (there is an iron worker and a 4ft wide hand break, plus several TIG and wire welders set up for aluminum).

[Grillage]

Eric, I think I have a spare belly pan here. Although it likely won't fit around the oil cooler

[cuatrokoop]

Hey Ben, thanks, but I'm not sure how Greg got his belly pan to fit, unless that bumper is some sort of hybrid. It looks like S2/euro-B4V6 lighting and the chin, but the grilles look taller and no license plate area like on a genuine Euro bumper like the one I have. The trailing edge where the belly pan would sit is vastly different than both of the US B3 and B4 belly pans I've tried so I either need to source an S2 or make something. I can cut/plas/bend/break/drill/punch/weld at work...

[A1QSHIP]

Here is a picture of an RS2 encapsulation panel. Notice the vent to help extract air out from behind the intercooler. Might work to move more air thru a front mount radiator. Looks to me that this would be doable on a B4 encapsulation panel with a little work.
HTH, Chris

[Mcstiff]

Hey Ben, thanks, but I'm not sure how Greg got his belly pan to fit, unless that bumper is some sort of hybrid. It looks like S2/euro-B4V6 lighting and the chin, but the grilles look taller and no license plate area like on a genuine Euro bumper like the one I have. The trailing edge where the belly pan would sit is vastly different than both of the US B3 and B4 belly pans I've tried so I either need to source an S2 or make something. I can cut/plas/bend/break/drill/punch/weld at work...

He modified his bumper to be more square.

[90quattrocoupe]

Hey Ben, thanks, but I'm not sure how Greg got his belly pan to fit, unless that bumper is some sort of hybrid. It looks like S2/euro-B4V6 lighting and the chin, but the grilles look taller and no license plate area like on a genuine Euro bumper like the one I have. The trailing edge where the belly pan would sit is vastly different than both of the US B3 and B4 belly pans I've tried so I either need to source an S2 or make something. I can cut/plas/bend/break/drill/punch/weld at work...

I do have a modified front bumper, but had the B4 belly pan on the car fit with the stock Euro V6 bumper. Early on, in 1996, when I bought the car, it did not have a belly pan. Audi service personnel like to remove them and not put them back on. The car had been serviced by a dealership, til I bought it. I ordered another one and the original belly pan was superceded to the B4 one. It fit with the stock bumper til I changed it out to the Euro V6 bumper in 2001 and it still fit. I had to trim the front a little when I modified my front bumper, in 2004. But other than that it always fit.

I will crawl under the car and take a picture. Give me a couple of days.

Greg W.

[90quattrocoupe]

Here are the photo I said I would post.

















Greg W.

[audifreakjim]

Amazing. If I didn't know any better I would say that car was only 5 years old.

[cuatrokoop]

Thank you, Greg. I'll have to see what belly pans I have in storage, I think I still have a couple left. Hopefully one is from my sister's old Cabrio. I'd still really like to get more room up front, a radiator like Greg's would do that and allow me to fit my H1/H1's with out modifying them (highly preferred!), but then I'd have to buy a new radiator and move the ABH oil cooler. I still have to fix the wiring to get some more of the gauges working as well, so if I did that it would be the time to pull the nose apart...

For some reason I didn't order the offset subframe bushings when I ordered the offset top mounts, so I'm going to order those soon.

[90quattrocoupe]

Eric, one of the options I thought about before having my copper/brass radiator made, was using the core from a Audi V8. The V8 core is pretty close to being the same size as the B4 core, but being aluminum, the end tanks can be fabricated to what ever you need. These B3/coupes, need some kind of custom fit radiator to work properly, with a V8. Off the shelf, does not seem to fill the need properly.

Dimensions for B4 radiator.
W - 61.5cm
H - 16cm
Depth of the flange around the radiator - 4.5cm

Dimensions for the V8 radiator
W - 62.5cm
H - 15.5cm
Depth of the flange around the radiator - 5.8cm

So the V8 is a little wider and the flange of the radiator is wider. Now some of the V8 flange can be trimmed, because it was designed to be crimped around the plastic end tanks. So the radiator can be narrowed. Now if you can find a radiator shop near you that does custom work, they can order pre-made cores. Then the end tanks can be made to fit. The fronts of the end tanks can be slopped back to clear the headlights.

I have included some pictures on the comparisons of B4 vs V8 radiators.









In this last picture, I wanted to show you the top plate I had removed from a B4 radiator and installed on my custom radiator. This way I could us the stock to mounting points to install my radiator. In the other pictures you can see the location of the lower b4 radiator mounts. I had lower mounts installed on my radiator in the same place. So I have all stock B4 mounting points on my coupe. Oh yeah, you have to run the lower B4 cross member for this to work, but they are not hard to find.

Greg W.

[Grillage]

Eric, there is a slightly narrower model of radiator that I could have used that would've fit between the headlights better. I think I put the part numbers of both earlier in the thread.

I just used the biggest thing that would fit between the lights themselves. I actually didn't realize the headlights would need trimmed until much later

[cuatrokoop]

Thanks guys, greatly appreciated. I don't think cooling will be a major problem, as the warmest I've seen was 88C in the warmer months when I first got it. Autocrossing will be the real test. There is a pretty good radiator shop here in town actually, and honestly I could have one of the welder/fab guys at work help me fab up and weld end tanks onto a core. I could also pull the current radiator and have the tanks modified for headlamp clearance. I'd mark the spots, cut them out and take a piece of aluminum conduit (sliced) and weld it in for a concave section. I'd like to think that the half-round profile would only create a minor flow impedance with minimal losses.

Also, I had three "sound damping pads" as Audi calls them, in storage. One was from my old '88 90. The other I believe to be my original CQ piece. The last one I found carried an 8A0 prefix. Bingo. Lists as a 1993-1995 90/90Q pad. It must have come off the Cabrio or my college roommates old '95 90q. Regardless, it has the NACA ducting like Greg's so I'll give it a go.

[cuatrokoop]

Going to get this thing dyno tuned down in C-bus before auto-x season (well, MY auto-x season) begins. A company down there is willing to work with VEMS, and they have an AWD dyno...