4kRR Audi 4000 Rally Rig

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Re: 4kRR Audi 4000 Rally Rig

Postby Wilford Brimley » Sat Apr 18, 2015 12:26 pm

I didn't think TR30r turbos were THAT expensive. I had the chance to buy a pair of them for $750 a number of years back, with a pair of spare turbine housings for $50 a pop.
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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Mon Apr 20, 2015 7:43 am

I've looked at the TR30r - $10k - $15k each. You should have bought those lol :) Might have been the same guy I was considering buying them from :)
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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Sun Jul 12, 2015 11:12 am

ok - believe it or not I'm finally getting ready to start this thing - but in doing all the necessary due dilligence, I've discovered that my Cam timing graph is fawking wrong - if anyone would like to verify my thinking that would be GREAT!!!!

So here's the thing - motor turns clockwise, that means that as you look at the graph, after TDC would be to the right of the zero mark and BTDC to the left as well as BBDC to the right and ABDC to the left. My original graph shows this relationship backwards. So, re-adjusting to this thinking - which I believe to be correct is attached (BTW also figured out that each tooth on the cam gear on the chain = 30 degrees on the crank and every 20.3 degrees on the crank is = 1mm of valve movement, so moving by a tooth = ~1.5mm of valve lift)
Attachments
CamIndex3b7a-TakeII.jpg
Cam timing w/7a ex and 3b intake
CamIndex3b7a-TakeII.jpg (112.82 KiB) Viewed 5972 times
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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Sun Jul 12, 2015 10:35 pm

in order to try to wrap my head around this - I built a model that shows the degrees of the crank and which stroke the piston is on. This helped my understand that the way I currently have the cams set, is exactly what you want:
1. Exhaust as piston begins descent on the intake stroke
2. both closed during compression and ignition stroke
3. no overlap when the intake and exhaust are open at the same time

Based on what we know regarding the duration open-to-close for each cam shaft as well as the lift, we can calculate that for the 7a exhaust, each degree of lift = .0985mm and for the 3b = .0798mm - given that we can build this model:

IntakeExhaustbydegrees.jpg
Intake and exhaust modeled by stroke type
IntakeExhaustbydegrees.jpg (210.69 KiB) Viewed 5964 times


this shows that the exhaust closes 12 degrees prior to the intake opening - there is no overlap and no danger of bending valves ...whew...

If anyone has thoughts on this - I'd love to hear about it
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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Sun Jul 12, 2015 10:42 pm

and there's more - in order to be able to tune at the dyno I've made a degree wheel that we can use to measure what's going on

2015-07-12 09.52.49.jpg
2015-07-12 09.52.49.jpg (3.01 MiB) Viewed 5964 times


downside of the 3b intake manifold is that you need to remove the TB to remove the valve cover :roll:
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Re: 4kRR Audi 4000 Rally Rig

Postby mr_aj_johnson » Mon Jul 13, 2015 10:10 am

Makes sense to me!
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Re: 4kRR Audi 4000 Rally Rig

Postby audifreakjim » Tue Jul 14, 2015 12:49 pm

This is awesome.
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Re: 4kRR Audi 4000 Rally Rig

Postby dana » Tue Jul 14, 2015 1:00 pm

this is really cool. Makes me sad to see you have that damn restrictor in there though. I suppose having that limitation is probably what is spurring you to geek out on this, so maybe its not so bad.
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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Tue Jul 14, 2015 1:30 pm

haha Dana - yep, trying to get as much value out of the relatively meager dollars I have compared to the big guns I'm racing against...I figure this information will help others and will certainly help me figure out what I need to do next...
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Re: 4kRR Audi 4000 Rally Rig

Postby deaner » Wed Jul 15, 2015 11:02 am

I wonder how the "powers that be" would react to a petition to changing the restrictor rule for regional classes. There's absolutely no way a small "weekend" team can compete with the bigger guys on 34mm. Something like a lower octane pump gas rule or something to keep power down instead of cutting our nuts off...
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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Wed Jul 15, 2015 4:47 pm

Coupe Du Quebec was on the verge of instituting something along those lines - you either run 91 octane or race gas - but always through the restrictor. The concept being that the 'big dollar' teams would run race gas and the weekender teams would run 91 - 'evening' things out as far as $$'s go...the ONLY reason it didn't fly is that there weren't enough race gas guys to have a meaningful class - bottom line, they are thinking in the right direction - oh, and you had to pre-buy gas for the event and from the organizers supplier - the supplier would then pump gas into your car at fueling in the service park - that way they could control the fuel quality.

They are thinking in the right direction - its just a matter of time...how about we put some race gas in this beatch then ??
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Re: 4kRR Audi 4000 Rally Rig

Postby deaner » Wed Jul 15, 2015 5:49 pm

I like that they're trying other things. I can honestly see how that fueling setup wouldn't fly very far. I wouldn't have an issue buying fuel from the organization as long as it wasn't stupid expensive. To me, as a newb still building my car, that fawking restrictor always pisses me off lol. Everything surrounding the sport is stupid expensive and that little thing in more ways than one, throws a bunch more cost and work on top. The off-road dirty bike racing I do has a "sprtsmans class" where you can run whatever you want, you just don't get any points. Keeps the faster casual riders from mucking up the points chasers scores as well as being a home for the guys that don't care about points and just want the experience. Works pretty well. Most people don't have the funds to chase a rally series around the country and end up only getting to one or two events out of the year, while they beat the piss out of it at local events in between. I'd love to see an "open, non restrictor" class that doesn't pay points. Cap it with shitty pump gas and draw in more people who just want to sling gravel a couple times a year. Just my opinion..
I plan on running RWD at first in the dirt lol.



Have you looked at any of the smaller framed holsets?
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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Thu Jul 16, 2015 8:48 am

US Performance Rally is overshadowed by very unfortunate spectator deaths that occurred in early 2000's - this led to SCCA dropping the sport altogether and lots of rules to make the sport 'safer' - the restrictor being one that would slow the cars down - agree or disagree - I don't see unlimited coming back with or without points :)

Prices were competitive on the fuel, perhaps 15% markup compared to a local station, which I would pay if it created better competition...

As for the holset, no, I've not looked at that - this particular turbo has been custom built by Hank Iroz specifically for a restricted application. We're going for lots of torque sooner - limited to about 250hp due to choke...we'll see after this weekend how the custom design works compared to a stock GTX2869 and a less efficient restrictor (I have numbers for that setup).
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Re: 4kRR Audi 4000 Rally Rig

Postby mr_aj_johnson » Thu Jul 16, 2015 11:14 am

Heard the noises this morning! congrats on firing her up again.
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Re: 4kRR Audi 4000 Rally Rig

Postby deaner » Fri Jul 17, 2015 9:32 pm

I agree, I don't see it coming back either. Just sucks because it's hard for a smaller to team to be competitive with the big guys. Luckily I'm just doing it for fun so stock turbo and RWD weeeeee.

I'm interested to see what you and Hank come up with. Any details you can share yet?
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Re: 4kRR Audi 4000 Rally Rig

Postby roortube » Fri Jul 17, 2015 9:49 pm

I know I'm late to the game here, and it may not work for you, but...

Last year I got an in cylinder pressure transducer for my Verus...it has become the single most valuable tool that ai own for diagnosing engine performance issues. I use it for many things, most relevant to your cam timing issues, checking cam timing with out removing any parts. You can graph cylinder pressure with respect to time and learn all sorts of things. This has helped me index cams (both or individual), diagnose failed lifters, valves, sensors, etc. If you already own a scan tool that will stream data from your car and has the capability to receive input from one, the $250 will be well worth it
Rob

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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Sat Jul 18, 2015 8:13 am

Very interesting albeit perhaps too late for this first go-around of tuning...which one did you buy?
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Re: 4kRR Audi 4000 Rally Rig

Postby roortube » Sat Jul 18, 2015 9:10 pm

I told the Snapon man I wanted one and he got it. I can check the part # next time I'm at work if you like.
Rob

Prepping my 91 M5 Dinan for sale to fund 07K and EFR build for my UrQ. May also sell Lotus Elan resto project. PM if interested in either.
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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Mon Jul 20, 2015 8:18 am

no worries - I'm sure I can source one when we go back to the dyno...and here are the results from the dyno...and there are always people to recognize that have helped on the journey:

Marc Swanson - EFI Express - this guy knows his business, has been tuning quite some time and prefers to play it safe with YOUR engine, unless you tell him not to. In Rally, due to the changing conditions - I prefer a safe tune. Also, keep in mind, the numbers below were taken on the hottest day of the year in NE - intercooler was well heat soaked and I would expect even better values in the fall...but for those hot days, I'm safe...

Hank Iroz - for the EM and turbo - ignore the numbers in the sheet - He took a GTX2862 and built a GTX28?? - inlet is 40mm, lets call it a GTX2840 not sure what the largest part of the compressor wheel size is.

Randy @ precision balancing in Hudson, NH - built the bottom end, balanced the crank, FW, damper...

Malcom @ Series Motorsport - did all of my aluminum tig welding - great shop, very knowledgeable guy!

Rob Shydo - helping to design the new restrictor - he did all the math!

Haydn @ HT Motorsports - for putting that design in to a form the machine shop could deal with

Ok - this is the old numbers - GTX2862, STR log manifold, sub-optimal restrictor (but really not horrible):
vittorioGTX2862_partial_pull_boost_reduced_same_torque.png
vittorioGTX2862_partial_pull_boost_reduced_same_torque.png (135.5 KiB) Viewed 5790 times


Next is GTX2840 (IMS flavor), efficient restrictor, IMS small runner EM, 7A exhaust cam, 93octane:
vittorio_93_2869.png
vittorio_93_2869.png (90.24 KiB) Viewed 5790 times


Next is GTX2840 (IMS flavor), efficient restrictor, IMS small runner EM, 7A exhaust cam, 103octane:
vittorio_103_2869.png
vittorio_103_2869.png (74.24 KiB) Viewed 5790 times


And finally an overlay of all 3:
vittorio_all_overlayed.png
vittorio_all_overlayed.png (130.72 KiB) Viewed 5790 times


Conclusions:
Restrictor improved HP numbers 10%-20%
Small runner EM, 7A exhaust cam and custom turbo improved spoolby 10% on 93oct and 25% on 103 as well as smoothed the boost curve
103octane, awesome early power, 370 ftlb @3100 rpm.

Running 93oct still produces 350 ftlb around 3300 rpm, but for much longer than the 2871 - which is pretty good when having to make the choice between race fuel $$ and pump gas...
Last edited by vbares on Tue Jul 21, 2015 7:53 am, edited 1 time in total.
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Re: 4kRR Audi 4000 Rally Rig

Postby alxdgr8 » Mon Jul 20, 2015 9:01 am

Wow, that is some awesome spool and early torque numbers!
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Re: 4kRR Audi 4000 Rally Rig

Postby WOMBAT » Mon Jul 20, 2015 10:47 am

Fantastic results! That's going to be a monster on stage..
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Re: 4kRR Audi 4000 Rally Rig

Postby groff » Mon Jul 20, 2015 11:01 am

Video or it didn't happen.
Looking forward to sharing the same stages with this thing!!
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Re: 4kRR Audi 4000 Rally Rig

Postby vbares » Mon Jul 20, 2015 11:02 am

See facey space for a video ;p
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Re: 4kRR Audi 4000 Rally Rig

Postby PRY4SNO » Mon Jul 20, 2015 11:27 am

The gain under the curve is pretty incredible. For an application where powerband is key you've done very well.
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Re: 4kRR Audi 4000 Rally Rig

Postby deaner » Mon Jul 20, 2015 4:01 pm

Holy cow! Well done!
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