MattWatson Matt Watson Ultra Moderator Location: Calgary Join Date: 04/17/2013 Age: Midlife Crisis Posts: 151 Rally Car: Merkur |
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vbares Vittorio Bares Mod Moderator Location: Londonderry, NH Join Date: 04/10/2007 Age: Ancient Posts: 413 Rally Car: Audi 4k (3b conversion) |
Nice ride - my wife has one as well - pretty rare. Dyno plot of 2871 with 34mm restrictor. Late spool...
I don't believe there is an option in Rally - did I miss something? AJ - thanks for the additional detail on the cams. I think I get why advancing intake would improve DCR...but that would assume the exhaust is fully closed, no? But, adding lift is no bueno? Is that about having a larger opening, increasing pressure and decreasing velocity? And, it seems to be the norm on a turbo application to retard timing as boost pressure increases - so with retarded timing, and advanced exhaust cams - I would imagine - that exhaust valve would need to start opening before the boom? |
Pete Pete Remner Mega Moderator Location: Cleveland, Ohio Join Date: 01/11/2006 Age: Midlife Crisis Posts: 2,022 |
The timing difference you posted between the 7A and turbo cams is just about negligible. The LIFT however is huge difference. 10-20% more lift without appreciable duration change is a win.
I can see why people scrap out 7As just for the cams Sad really. Pete Remner Cleveland, Ohio 1984 RX-7 (rallycross thing) 1978 Silence is golden, but duct tape is silver. |
Morison Banned Professional Moderator Location: Calgary, AB Join Date: 03/27/2009 Age: Ancient Posts: 1,798 Rally Car: (ex)86 RX-7(built), (ex)2.5RS (bought) |
He's building a 2wd turbo car... which can run at a lighter weight with a restrictor in Canada. First Rally: 2001 Driver (7), Co-Driver (44) Drivers (16) Clerk (10), Official (7), Volunteer (4) Cars Built (1), Engines Built (0) Cages Built (0) Last Updated, January 4, 2015
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Josh Wimpey Josh Wimpey Mega Moderator Location: VA Join Date: 12/27/2006 Age: Midlife Crisis Posts: 649 Rally Car: Sneak the Golf |
The dyno chart picture is small but if I am reading it right, it looks about the same as mine but the restrictor chokes yours just as the fun has barely started. I am sure that someone who has done the math has a better answer but if the theoretical limit to airflow is 29lb I would look for a turbo that moves that much air at max efficiency?? The 2871 moves closer to 45lb or so Garret used to make a Rally specific GTX2860 optimized for 34mm https://www.turbobygarrett.com/turbobygarrett/turbocharger?productCd=GTX2860R (Rally) ____________________________________________________________- One. Class -- 2WD www.quantumrallysport.com http://www.facebook.com/home.php?#/pages/Quantum-Rally-Sport/281129179600?ref=nf |
MattWatson Matt Watson Ultra Moderator Location: Calgary Join Date: 04/17/2013 Age: Midlife Crisis Posts: 151 Rally Car: Merkur |
Woops. Yep, didn't check where the post was from. Yep, Canada. And... I think my description of weight penalty is a pretty good one, the other cars dont get lighter... I get to add weight, no matter if I run a restrictor or not. And we have pretty much established that all in, no doing any lightening of the car at all, I will have to add around 300lbs. But I do plan on adding the restrictor it once the other teething problems are resolved, so it does need to be removable... well at least 200lbs of it since I am still saddled with the 2700lb min weight due to the fact that it's a 2.3L. |
Morison Banned Professional Moderator Location: Calgary, AB Join Date: 03/27/2009 Age: Ancient Posts: 1,798 Rally Car: (ex)86 RX-7(built), (ex)2.5RS (bought) |
Six and half a dozen. The smart thing to do would be to talk to the regions an make sure they will still be allowing group 5 in the regional events and don't worry about the ballast. (You basically can't enter national events until you have two regional events under your belt anyway) First Rally: 2001 Driver (7), Co-Driver (44) Drivers (16) Clerk (10), Official (7), Volunteer (4) Cars Built (1), Engines Built (0) Cages Built (0) Last Updated, January 4, 2015
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john vanlandingham John Vanlandingham Super Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Turbo Compressor Turbine
Turbo PN CHRA PN Ind Whl Dia(mm) Exd Whl Dia(mm) Trim A/R Whl Dia(mm) Trim A/R 816364-0001 446179-92 45.70....... 60.00 ......58 0.60 53.90 76 0.86 That compressor wheel is arf-fully close to a stock Xratty compressor wheel----which also just so happens to be 4x4 Cosworth Compressor wheel, and just happens to be Lancia Delta Intergrale 16v 409096-0013 60,00 46,50 5,00 6,00 60 Jeeze seems everybody who I talk into slinging a 4x4 Cosworth turbine housing onto their ordinary boring Xratty turbo always raves about hard boost at 2200 or so... Could it be that both Lancia and Ford really teams maybe knew what to use for quick spool and revs? John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
MattWatson Matt Watson Ultra Moderator Location: Calgary Join Date: 04/17/2013 Age: Midlife Crisis Posts: 151 Rally Car: Merkur |
Disagree 100%, not six and a half dozen. If I was running a 2.5 NA motor, I could run at least 300lbs lighter, than if I was running a restrictor turbo at 2.3. If I have to add weight (not avoid removing weight) then it is absolutely a penalty.
Which I did as soon as you guys 'gathered' feedback on the proposal. They are keeping it, until they don't of course. Edited 1 time(s). Last edit at 06/09/2014 10:34PM by MattWatson. |
MattWatson Matt Watson Ultra Moderator Location: Calgary Join Date: 04/17/2013 Age: Midlife Crisis Posts: 151 Rally Car: Merkur |
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john vanlandingham John Vanlandingham Super Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
300 lbs!!! That's going to be a monetary penalty of between $800 to $1000 at US prices, PLUS SHIPPING... Meh...it's only money...if you want to enter a National you have to play by the Rich Guy Rules. because its obvious they don't want you in their precious events.. John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
aj_johnson A.J. Johnson Infallible Moderator Location: Pendleton OR Join Date: 01/07/2011 Age: Settling Down Posts: 1,381 Rally Car: 88 Audi 80 |
vittorio, as far as I can find the rally fords run about the same lift (a hair less), and the duration difference between the 7a and aan is pretty measly. The few 7a dyno vs aan dyno plots I was able to find show a loss under 2800 but it seems that most of the powerbands match or cross right around that area.
I think its worth the risk, if you need a cheap set to try out give me a call. I'm headed to boise on friday and the guy has two 7a's laying around. prolly could snag em for 100 or so. As far as clocking the cams, I see a little gain but loads of time finding the sweet spot. How much time do you have? |
Morison Banned Professional Moderator Location: Calgary, AB Join Date: 03/27/2009 Age: Ancient Posts: 1,798 Rally Car: (ex)86 RX-7(built), (ex)2.5RS (bought) |
We'll agree to disagree then. I see it as class compliance, not a penalty. Anyone who builds a 2.3 turbo 2wd car faces the same class compliance requirements. A penalty is the $500 when you leave your triangle behind or the 10 seconds added to your time for being clocked at 11km/h over the speed limit on transits. Don't know what you're trying to say with the quotes around 'gathered...' I fully expect the events in the west will retain Gr5 as a class for the foreseeable future. That doesn't mean you can sit back and let the events and regions run themselves... the annual meetings are open to anyone who wants to come out to them and being a voice for keeping Gr5 as a regional class is important. (Entering events is actually more important, but coming out to the meetings helps both the organization and you in many ways) Don't, for a second, think that anyone doesn't want your entry at events. Nothing could be further from the truth. First Rally: 2001 Driver (7), Co-Driver (44) Drivers (16) Clerk (10), Official (7), Volunteer (4) Cars Built (1), Engines Built (0) Cages Built (0) Last Updated, January 4, 2015
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vbares Vittorio Bares Mod Moderator Location: Londonderry, NH Join Date: 04/10/2007 Age: Ancient Posts: 413 Rally Car: Audi 4k (3b conversion) |
I've added a couple files - comparison of the dyno curves GT2871R v. GTX2862
John - very interesting on the various makes and the turbo's they've used. I'm not in tune with the Ford world and don't think to look - just keep hammering the idea and eventually it will sink in... Attached is a comparison of turbo's I've looked into. The Garrett GTX2860R (Rally) costs $5k - not doing that as it is not sustainable on my budget. So for the Turbo - I'm working with a guy that will mod the turbine from a GT2871 (which I had as a spare) to more align with the GTX2860R (Rally) without the rape part of the transaction. As for cam's - one of my sponsors is willing to work on the dyno to dial the cams in. AJ - I'll ping you before thurs. if I can source the cams locally - probably better... |
NoCoast Grant Hughes Junior Moderator Location: Whitefish, MT Join Date: 01/11/2006 Age: Midlife Crisis Posts: 6,818 Rally Car: BMW |
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