914RS4 Tube Chassis 996 Suspension Audi 2.7TT Stage 3, ADDED RECAROS Options

[Cracker]

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

[Andyrew]

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.

[Cracker]

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

[Curbandgutter]

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. (IMG:style_emoticons/default/stirthepot.gif) (IMG:style_emoticons/default/stirthepot.gif)

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. (IMG:style_emoticons/default/shades.gif)

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.

[jd74914]

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. (IMG:style_emoticons/default/stirthepot.gif) (IMG:style_emoticons/default/stirthepot.gif)

....

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! (IMG:style_emoticons/default/beerchug.gif)

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.

(IMG:style_emoticons/default/ar15.gif) (IMG:style_emoticons/default/laugh.gif) Equal length headers fix that pesky noise issue...and make the 6's sound like 911's... (IMG:style_emoticons/default/rolleyes.gif)

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.

[Andyrew]

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 (IMG:style_emoticons/default/smile.gif)


Dyno for comparison.
(IMG:http://www.914world.com/bbs2/uploads_offsite/farm4.staticflickr.com-172-1484680781.1.jpg)

[Curbandgutter]

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.

[csdilligaf]

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.

[Andyrew]

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.

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

[Curbandgutter]

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.

Thanks just corrected it.

[Curbandgutter]

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.

[jd74914]

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...

Jim, your tractive force spreadsheet proves that if you shift at max torque you will drop the tractive force substantially. It proves that shifting is better near max horsepower. I just did a spreadsheet for my car. Very interesting information. Thanks for illuminating me.

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! (IMG:style_emoticons/default/smile.gif)

[Curbandgutter]

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

[tygaboy]

Rudy - That's looking wicked! (that's a good thing...) (IMG:style_emoticons/default/aktion035.gif)
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

[Curbandgutter]

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.

[Curbandgutter]

The donor has landed.

[tygaboy]

Delete

[tygaboy]

The donor has landed.

I'll say... and pretty hard, based on that pic! (IMG:style_emoticons/default/lol-2.gif)
Keep the coolness coming, Rudy!

[76-914]

Donor car #3? I knew of the 2 Porsche donors. What is the Audi donating? (IMG:style_emoticons/default/beerchug.gif)

[Curbandgutter]

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