Little update, should be able to finish tying in the front struts to the tube chassis. A couple of progress pics.

Here is the strut attachment point cut down to size. I had to move the tower out and forward to account for the strut inclination angle both sideways and forward and backward. Click to view attachment

Here is the octagonal shape that I will be using to box int he strut tower Click to view attachment

Here is the "strut brace" Click to view attachment

Forgot to add this mock up. Test fit of parts before tacking them in. Don't worry the tubes will line up.

You know one thing I would like to plan on is moving the driver over a little so you can square up with the pedals. You already are making your own center console box so its a no brainer at this point. The front end progress looks good. Its a big undertaking for sure but your doing an impressive job. Keep it up

The weather let up a bit and I was able to sneak in some hours into tying the strut towers in. By the way I am really giving it some heavy consideration into changing engines. I'm leaning to a Audi RS4 Stage 3 motor. It will produce 600 HP so its where I want to be. What do you guys think about that motor choice.

The weather let up a bit and I was able to sneak in some hours into tying the strut towers in. By the way I am really giving it some heavy consideration into changing engines. I'm leaning to a Audi RS4 Stage 3 motor. It will produce 600 HP so its where I want to be. What do you guys think about that motor choice.

A short passage from a book I think I'll write about Rudy:

"It will produce 600 HP so its where I want to be." He said this casually, as though this level of power was commonplace, even easily attained or available without much planning. He was, as everyone already knew, power hungry. He would come to look at his initial 600hp as "a decent starting point". Eventually, he printed t-shirts with this slogan on the front pocket:

If more is good then too much is just enough!

On the back was printed "I'd rather be sideways".


_________________________


Rudy - I vote "Go for it!"
Your build is looking awesome.

You asked Rudy...

I am not a fan of the Audi 4.2 RS4 engine...I saw a nice conversion done into a Boxster race car - very underwhelming. It is low on torque and wasn't competitive either...honestly, I don't care for the sound too. There is a high-price to pay when squeezing big power out of small displacement motors - I know all about them, first hand. Synonymous with hand-grenade.

Remember, you asked!

T

PS: Although both heavy and large - I've thought the GTR TT v-6 would be a nice addition to the 914. Audi have already been done...

PS #2: I'm digging your progress - great job!

4.2 tt rs4 motor? Thats a lot of weight to make that much power.

Its a compact and complicated setup but 600hp is easily made on that setup and it should be extremely torquey.

I think if It were me it would either be the rs4 NA v8 or a S8 4.2 motor for about 360hp to be more economical.

If I wanted to go turbos again with an auto motor I would go 2.7 built with gt28 turbos or KO4 hybrid turbos. That would put a power range from 325-800hp.

Andyrew, I think you nailed it with the Audi 2.7TT.

Nice strut towers Rudy! They look like really stiff nodes!

The Audi 2.7TT might be a good motor if you want to keep it German. Otherwise a Subaru EG33 or EZ30R with some turbos might work well too-and they'd help lower your CG to boot.

Why are you thinking of moving away from the Coyote? AFAIK they are pretty robust motors to ~650hp (forced induction).

I would love to see a small displacement motor - probably a six-cylinder - with quad turbos - since you are ambitious. A target of 600-800 hp at the crank would be fantastic. I have changed my tune on what is "usable in a 914" since my car is so composed with only 590 hp...my car with a 275 rear could hold another 100 easily. Looking forward to what you choose - even if it is an RS4 variant. Cheers.

T

No need for extra complexity with extra turbos. Thats not going to gain power, just response. The 2.7 is plenty responsive with appropriately sized turbos or even just a single turbo like a precision 6262.

The biggest thing to do with turbo cars is pick the right turbo/s for the motor to eliminate boost lag and pick turbos that will efficiently work within the power range your looking for. From there you build the motor to handle the power, make it efficient and then start pumping in boost, timing, and fuel to make power.

My turbo system is a hair lagy but its only a 1.8L displacement, my efficient boost pressure range is 10-35psi letting me tune my boost curve how I want it. I can either turn the timing and boost up down low for the most torque I can make which will blow the tires off as quickly as possible and break things. Or I can give it medium hit and ramp the boost up as it gets higher in the RPM or time in gear to allow for more potential traction yet higher overall acceleration.

I do not know Rudy personally (but anyone taking this on - I'd like to meet) but through watching his build (much like Chris too) - it appears he wants to chart new ground - so to speak. The added complexity is the bait to chase - not the obstacle to be avoided - for the rare bird like Rudy that is! JMHO

Twin turbo's, superchargers, vee-eights, etc have all been done adnauseam - a quad turbo set-up on a hot v-6 with DI would be epic. If Rudy isn't that motivated to build something truly unique, I get it. I am not (but it would be otherworldly!)...

T

First of all thanks for the replies you guys don't disappoint.

Tygaboy
"If more is good then too much is just enough!
On the back was printed "I'd rather be sideways".

Haha you are crazy. I'm really going to love meeting some of you guys at the events once my car is complete.

Cracker

"I am not a fan of the Audi 4.2 RS4 engine" neither am I. CSDILLIGAF has succeeded into talking me into the Audi 2.7 V6 twin turbo.

jd74914
I thought you'd like those strut towers. I still need to add some gussets. I'm kind of steering away from the coyote for a couple of reasons. The coyote is a great motor but Chip has swayed me into the 2.7 audi because you don' t need adapters and special clutch assemblies. And, I like the way that turbo'd cars pull. Additionally since we will be doing the same exact car, we can brainstorm and have a better chance of success.

I totally understand the CG issue but I just don't like the way that 4 bangers sound.

Cracker
Thanks for the compliments. You and Tigaboy are so hilarious in your writing styles.....I love it. Sorry to let you down though, but no quad turbos, two is enough. I think that the pull on the 2.7 will be enough to give passengers vertigo. I'm hoping that the car will get better traction with a controlled power band up high than down low where it will just cause wheel spin. It's nice to know from real world experience such as yours, that the 914 can handle an additional 100 hp over your 590. Wow that says so much for the amount of performance that is locked up in these little cars that we love. I look at the fact that my car's track is now 5 inches wider, the wheelbase is now 3 inches longer than a stock 914 but 7 inches longer than a 911 and a chassis that will be at least three times as stiff as a 911 and weighing as little as a stock 914, I feel confident that it will not disappoint. It is quite telling that the new 911 is the same wheel base as a 914.

Andyrew
The 2.7 will have the twin RS6 RS turbos.

I'm getting really close to bolting up the suspension. Just need a couple of gussets and the roll bar diagonal and it will be ready for the suspension. Then I'll replace the floor and close up all of the holes I made to insert chassis into the chassis. I will be adding shear connections along the floor pan, the dash and the targa to transfer loads between the chassis plate elements and the tube chassis axial members. In other words tie both chassis together so that they supplement each other where the other is weak.

As odd as it sounds they are my favorite part of the car!

That makes perfect sense. Using components which are designed from the factory to bolt together is much better. I've personally never been really impressed with the adapter plates/flywheels-too finicky and too unique to the combination. Having two test mules should make it much easier to wring out all of the problems too.

Equal length headers fix that pesky noise issue...and make the 6's sound like 911's...

Can't wait to see the shear panels!!

Do you have any ideas on what a 2.7TT dyno plot might look like? Or your gear ratio's/final drive? Just curious as to what the tractive force curve might look like. If you have some numbers I can throw them into a spreadsheet I have and send it to you.

2.7 with RS6's should be a lot of fun. Are you going to get the JHM one's?
https://jhmotorsports.com/shop/catalog/jhm-...th=21_56_60_100

What engine management and fuel are you going to go with? We could talk Audi engines all day...

It will be interesting to see how you build the motor, what you do with fueling, engine management, tuning, clutch, ect ect.

The 2.7 is a nice sounding engine, I will give you that


Dyno for comparison.

Andyrew

Yes the JHMotorsports ones. By the way that looks like it may be the dyno sheet for the JHMotorsports RS6 car? Is that it? From reading your posts and the impressive tuning that you have done it looks like you will be an excellent source of input on the Audi stuff.

JD74914 here are the gear ratios

1st gear 3.307
2nd gear 1.95
3rd gear 1.407
4th gear 1.133
5th gear 0.972
6th gear 0.822
Final drive 3.875

Rear tire will be 335/30-18

Put it in your spreadsheet or if you can, send me the spreadsheet and I'll post the numbers.

Rudy, the gear ratio's on the G87.21 have taller 1st and 2nd gears as listed on the California Motorsports page. They are 3.307 for 1st and 1.95 for second. That's another reason to use the G87.21.
Plus your tire is a little taller than mine. Yours is 25.9 so you can stretch out the revs more than mine.

Here is where I pulled that sheet from. I have no other info than what he posted. I imagine its wheel HP on C16 or similar since its so high.

http://www.audizine.com/forum/showthread.p...l=1#post9227384

Thanks just corrected it.

JD74914 I calculated the tractive force based on the Boxter S G87.21 gear ratios and the S4 Stage 3 Dyno plot and this is what I got. Seems like a smooth transition. Looks like Porsche knows what they are doing in selection the gear ratios.

That is a nice smooth parabolic curve-perfect! That's what I've noticed too. If you plot curves from many manufacturers there are some big gaps, but Porsche and Subaru seem to have the gear selection thing down pretty good (for the ideal "go-fast-car" case).

I pulled it last night too and got a very similar curve...sorry I didn't get a chance to post to save you the work. I pulled a number of gear ratios from CM's website and the G87.21 really does seem like a good choice. It's a shame first gear isn't slightly longer, though this seems to be a "problem" in almost all gear boxes (it's really bad in sport bikes).

Copied this from my thread...


Yeah, it's a rather interesting plot since it brings out things you usually wouldn't think about. It also does a good job of justifying peakier, higher overall power engines vs. these flat torque curve monsters. Glad it could be of use!

Finished the strut towers with the gussets that were needed. I should be able to bolt up the full 996 suspension this weekend

Rudy - That's looking wicked! (that's a good thing...)
Can't wait to see the suspension bolted on and this thing on wheels. I'm waiting anxiously to see the extended wheelbase and how you're planning to mod the body, etc. Any details or plans you can share now? Inquiring minds want to know...

Either way, keep the great work and progress pics coming!

Chris

Wow I though that the rear shock towers would take me about an hour each and it took a full 10-hour day to complete both! Anyway here are pictures of the rear shock towers. I took a piece of 6" channel and made a paper template and cut with plasma cutter. Ohh...I'm picking up donor car today. It is a running Audi S4 with 130K miles. Picking it up in Van Nuys tonight. The only major thing left to purchase will be a boxster transaxle. I was hoping to be able to bolt up suspension but that will have to wait until next weekend.

The donor has landed.

Delete

I'll say... and pretty hard, based on that pic!
Keep the coolness coming, Rudy!

Donor car #3? I knew of the 2 Porsche donors. What is the Audi donating?

996 donated the legs and feet. Donor 914 donated moral support. Audi S4 is donating heart and lungs.

My Audi Donor was the same way. A little love tap in the back end leaving a perfectly good running 2.7TT up front.

Yep exactly! Drove it right up onto the trailer. Fires right up.

What are your plans for intercooling -- air/air or water/air?

For simplicity ( I know it's an oxymoron for this build) I am going to use the factory setup. I think that it is air/air. Since I am planning to open up the back end 2 1/2" on each side to accommodate the wider 996 track, I will take advantage of that and place an intercooler on each side but most likely 50% larger and mounted vertically. I will fold the rear 1/4 panel into them and create a reverse scoop to drag air into them. I plan on venting out through the rear in between the tail lights with some type of expanded metal. Maybe like the one that is on the engine lid.

Factory intercoolers are air to air and are not very efficient. They make thicker intercoolers specifically for the S4, specifically chineese versions that are very affordable. Combine that with E85 or W/M injection and you should be good for a considerable amount of HP.


I would go something a hair larger like this if your considering staying air to air.
http://www.ebay.com/itm/Rev9-Turbo-Side-Mo...XMO&vxp=mtr

But you would probably be better off going with a pair of bar air to water intercoolers and just mount a single large radiator in the fender.
http://www.ebay.com/itm/Liquid-Air-Interco...C7z&vxp=mtr

Noticed forged diverter valves, Thats a plus

Pull the ECU and see if there are any markings on it. I bet at the very least this car was tuned, probably sell that ecu for an easy buck if your going a custom engine management system.

There really is not an affordable option for a stand alone engine management for this motor. There are people who tried with a $5K version or more and had nothing but trouble and never got it to work right. We want to build a car, not take a year to learn what others already know and are good at. The factory ECU has a huge following and tuners with the education and skill it takes to hack and do what ever you want are plentiful. I have found Motoza Performance to be the best, easiest, most helpful and cost effective. For around $400-$500 they give you the software to reflash the ECU, the cable to do so from a laptop and OBD2 port and the first version with the basic tune. This allows you to get up and running and run the data logging that gets emailed to them and they will tweek things until you are happy. If later you go up to bigger turbo's or go to E85 you just pay the difference of the two stages pricing and they help you out again.

Andrew thanks for your input. But yes we're sticking to stock engine management with tuners that work with them. Thanks for the info on those forged diverter valves, I didn't think they were stock but really didn't know what I was looking at. I have a lot of learning to do on this motor. I'm glad you're around so that I can glean information from you. As far as intercoolers im thinking of going with this company http://bellintercoolers.com/how-to-order/c...ickness-airair/

Ok so now I'm the owner of a Cayman S G87.21 transaxle. Should be here by Feb 6th. Well looks like I'll be pretty busy from here on.

Megasquirt has been effectively utilized on that motor, but I agree the factory ECU is more than capable. I am utilizing the factory ECU as well and know it has and will support my setup just fine as I ramp up the power.

Seriously pull the ECU, Most tuners will mark it. You might find it tuned by a reputable tuner who will set you up on a big turbo file and give you advice on what you need injectors, fuel pump, maf, ect ect.

Custom intercooler is a fantastic way to go on a project of this nature. If you have the ability to weld aluminum I really think you should build a twin air to water intercooler setup in front of the engine (you will have plenty of room).
This will allow you to keep the intake plumbing short and in the engine bay vs having to shoot to both sides of the fenders. Should help with spool as well.

Looks nice. Going to get a LSD for it? What did you pay for it?

Yes LSD from CMS motorsports. Chip already had his done. Paid $1650

You can't go wrong with anything from Bell. If you need technical support Gerhard Schruf is awesome! I've bought air-to-air and air-to-water intercoolers from them a few times (industrial usage but really no difference from automotive) and their prices really aren't too bad considering the quality.

CMS motorsports sells and installs the Wavetec LSD. They are $1255 plus install. Everyone has good reviews of it and it is made in the USA so I will give it a try. I have always had Quaife so the Wavetec will be new for me. Anyone have personal experience with them?

Well tranny came in today. Lifting car off of jig tomorrow. Will do a twist test before installing suspension. Huge milestone

Good for you...congratulations!

T

Well she's off the jig. Im going to try and do the twist test today. However, I have to smoke a briskett for the super bowl so the twist may have to wait.

Bolted up rear suspension. After everything is dialed in, I will bead blast the entire suspension and powder coat the calipers in red.

Looks like you stretched the wheel base just the amount you wanted too. Looks good. And the one tube you thought would be close at on the rear suspension looks like it just cleared. Can wait to see it on the ground with wheels and tires.

and I'm going to take a wild guess that csdillgaf and I aren't the only ones who're chomping at the bit to see this bad boy as a roller. So, Rudy, hurry the hell up!

We want video of you sitting in it, on a milk crate, steering wheel in hand (bonus points if it's not even mounted on the column) doing your best impression of turbo flutter/blow-off valve/waste gate noises!

Come on, we're waiting:

And of course you know what I really mean by all this idiocy: LOVE your build!!! Can't hardly wait to see the progress each post.
Chris