Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

931 (Woody) project
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8, 9  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Discussion
View previous topic :: View next topic  
Author Message
Mike9311  



Joined: 14 Dec 2004
Posts: 878
Location: Chicago-ish

PostPosted: Sun May 17, 2020 7:50 am    Post subject: Reply with quote

My two cents on S1 boost and I am thinking I was super lucky to have an S1 with all this S2 reading I have been doing lately. Youthful ignorance running amuck and enjoying every minute

I regularly ran my S1 at 10-12psi for 2 years with a HKS EVC-1 (Long time ago!) which I still think is a wicked controller only in that it had three buttons effectively. Two boost levels buttons plus the adjustable knob which was also a button.

On colder days, aka turbo weather, I would run intermittent high boost to 15psi simply by pressing buttons on the controller back and forth. It seemed to like 12-13psi worked the best though on those days

No intercooler, an S1 2664 compressor, and 4.10 housing.

This car was run hard and for long 800 mile stretches with two guys switching up driving duties

When I parked the car in '91 and pulled the head everything still looked fine.

Point is, the S1 seems to be more forgiving and 10-11 should be just fine. Of course being able to turn it down on a hot day is a nice option.
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
jacobroufa  



Joined: 18 Nov 2016
Posts: 286
Location: Rockford, IL

PostPosted: Sun May 17, 2020 11:21 am    Post subject: Reply with quote

Cedric, I was thinking the same thing, and to be honest if I weren't itching to continue driving it so badly I would have done just that last night. It's on the list for when I replace the rear brake hoses.

I have had an impact driver on my list for awhile and I keep putting it off because dumb reasons. With as many cars as I have, I really owe it to myself though so I should follow through on that soon.

Rest assured though, Dan, PB was a part of the equation! Those big bolts and nuts were the first ones I hit after I got the wheels off. I really honestly just didn't have the right leverage.

Mike, I cannot wait for more boost. Everyone keeps saying that about an S1, and the more I drive this car the more I understand that 6psi is really just a tickle. It will happen eventually, but I feel like if I don't start chasing that right away my wallet will be safe for a bit longer. That said, I really really am kicking myself for not participating in the liquid intercooler group buy from 6 months ago... I will have to find one of those things one day. Thinking about any other type of intercooler install seems pretty daunting; they all require so much work, whereas that one is fairly bolt on.

Who knows. Maybe Dan has extras stashed away.

---

So today I had other things to deal with at home and I didn't do what I said I would to the car. I drove it instead. Several decently long drives too. My daughter (7yo) asked to go for a ride so we did. It was a giggle-fest.

I really like the change with the bigger sway bar in the rear. It's hard to tell completely because the front is so worn out and those bumps translate through the chassis. But if I had to say, I would say that the car stays flatter. It was harder to push out the rear end today, felt more on target.

Tomorrow is going to be rainy says the forecast, so the front suspension work will have to wait for evenings this next week.
_________________
1980 Porsche 931
1981 Porsche 924 Weissach
Back to top
View user's profile Send private message
CÚdric  



Joined: 27 Aug 2004
Posts: 1994
Location: Sweden

PostPosted: Sun May 17, 2020 5:11 pm    Post subject: Reply with quote

Borrow or buy a wideband lambda and check the fuelling before the boost adventures. 1 or two points of AFR is the difference between running great and hole in piston territory on these cars.

Are you on the 924 turbo/gts/gtr Facebook group? I made a thread there with a massive collection of different 931 intercooler solutions that people could take a look at as inspirational. Not sure it must end up that much harder than water IC, it needs plumbing, pumps+electrical, radiator etc
_________________
┤80 924 Turbo
Back to top
View user's profile Send private message MSN Messenger
Fasteddie313  



Joined: 29 Sep 2013
Posts: 2039
Location: MI

PostPosted: Sun May 17, 2020 7:39 pm    Post subject: Reply with quote

CÚdric wrote:
Borrow or buy a wideband lambda and check the fuelling before the boost adventures. 1 or two points of AFR is the difference between running great and hole in piston territory on these cars.


Completely agreed, especially if you are talking no intercooler..
No intercooler is danger imo.. Fuel will need to be spot on rich enough not to blow but not so rich it bogs..
I'd imagine like high 10's-low 11s.. Anything under like 10.7 starts loosing a lot of power fast..

I've been running stock boost pressure in like the mid 12's I think..
Leaner spools faster and feels like it makes more power..
I think I'm looking for like 11.0-11.5 at max boost, but I'd run 1 bar 11.5- 12.0 on mine..

Intercooler just makes it feel so much better..
I think just adding the intercooler gave me just about as much more power gain as bumping up to 10-11psi..
Adding an IC I feel probably gave me like 10% more power right there..
It was WOW..

CÚdric wrote:
B
Are you on the 924 turbo/gts/gtr Facebook group? I made a thread there with a massive collection of different 931 intercooler solutions that people could take a look at as inspirational.


Link? I don't FB much..

I might be biased but I still like my IC setup the best..
It just fits/looks so good from the front IMO.. Watch from like 1:40 https://youtu.be/DfabJaLFaA4

I still have my stock charge tubes, stock windshield washer, keeps the pop up lights, almost no cutting anywhere.. Stock oil cooler and lines.. IC only costs like $65 and is pretty big, thick core, super sturdy mounting, nice IC to rad spacing..

It took me a hundred hours of thinking to figure it out, but I could probably install it on a car (except 2660) in like 3-5 hours of patient work now.. Now that I have done it like 5 times..

Just need some angle iron and pipe.. No welding or cutting off body panels..

Little NVH from the rad fans though.. Rad isn't soft mounted anymore.. Front lip of the car is as stiff as a board now though.. My mounts really stiffen up the lower valance..

Stock radiator.. Stock rad fans.. Cool as a cucumber..
My logs up to 1.15 bar of coolant temp and IAT/MAT are great..
Even doing donuts the fans keep it cool..

With the way Cedric installed his BOV it would just look 100% stock under the hood, and I love that..
If I did it again I think I would put my BOV down below like Cedric did, but I still like my IC fitment and pipe routing off the comp a little bit better than his, which is almost exacly like mine otherwise..

The top mounts are cool and easy looking to do but I have my doubts they can match the performance of a Front Mount..

I think Rasta's watercooler in the batttery box is a little bigger/better than Dan's, but not as "bolt on" as dan's..
TBH I'm not a huge fan of watercoolers though.. Maybe it's just me but I just don't feel the physics of it doing quite as good of a job in most situations..

I've seen some logs of the 951 style IN installs as far as temp numbers, but I just don't see where it gets enough airflow from.. And those require more bodywork than I'm willing to do.. The thought of cutting the nose off of my car is scary..

Morghen had a nice FMIC on his red car but I believe it required a 951 front end and removing the washer tank iirc..

Someone has a nice FMIC with the pipes coming down infront of the headlight tortion bar, but I forget who right now.. Old thread..

The ultimate ICs I think are like in the GTR cars, the BOSS car, jaquime's car, the car CarreraRSR got his exhaust from, but those are nowhere near stock cars.. Drastic modifications..

IDK
Lot of methods to choose from..

The only other thing to worry about is the head gasket..
If you have an old stock head gasket under stock bolts it might not last too long..

It would probably be best to go with an MLS HG and ARP studs.. <$300

If not then just keep a real close eye on it..
Mine started leaking and I replaced it with an stock gasket and ARP studs, and it's holding for now.. But I'll likely be back in there again to install an MLS eventually...
Kinda like the idea of the "cutring" HGs the BMW gus use too though, and I think they are avail to fit our bores..

Pistons are supposedly another concern, but I think that stigma might be a lot from guys not running intercoolers..
I think a good IC will save the pistons but I guess I'll find out..

Stock fuel system is good to 1 bar no problem.. According to my tests it will spray like 330 HP worth of fuel, so I figure it would be good to 250HP or so conservatively..
I should have ran longer/harder on my stock fuel system, but I fell in love with the V8 fuel distributor thing, so I don't have any logs of te stock fuel system...

I ran my stock fuel system up to about 15psi, and my HG started leaking a little, so there came a huge project, and the end of my stock fuel system in the process..

EFI is also a thing, but I didn't do that because I'm crazy in the head..


Have fun..

How much money and time do you want to spend on making power?
You know this engine isn't going to make stupid power no matter what you do right?
I think if you want a 600-1000 HP car this engine is about like pissing into the wind.. Not gonna happen..
But if you want to do all the same work for a 300-400 engine, the old Audi van 2.0 might be the engine for you....
_________________
80 Turbo - Slightly Modified
Back to top
View user's profile Send private message Yahoo Messenger
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2010
Location: Somerset, UK

PostPosted: Sun May 17, 2020 7:56 pm    Post subject: Reply with quote

Mike9311 wrote:
My two cents on S1 boost and I am thinking I was super lucky to have an S1 with all this S2 reading I have been doing lately. Youthful ignorance running amuck and enjoying every minute

I regularly ran my S1 at 10-12psi for 2 years with a HKS EVC-1 (Long time ago!) which I still think is a wicked controller only in that it had three buttons effectively. Two boost levels buttons plus the adjustable knob which was also a button.

On colder days, aka turbo weather, I would run intermittent high boost to 15psi simply by pressing buttons on the controller back and forth. It seemed to like 12-13psi worked the best though on those days

No intercooler, an S1 2664 compressor, and 4.10 housing.

This car was run hard and for long 800 mile stretches with two guys switching up driving duties

When I parked the car in '91 and pulled the head everything still looked fine.

Point is, the S1 seems to be more forgiving and 10-11 should be just fine. Of course being able to turn it down on a hot day is a nice option.


Correction - USA S1 2664 4.10.........RoW S1's had 2470 6.10.

Having the 2664 and increasing boost probably saved you melting a piston as the 2470 is a heat pump before increasing the boost. More boost just sends intake temps skywards
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2010
Location: Somerset, UK

PostPosted: Sun May 17, 2020 8:25 pm    Post subject: Reply with quote

Fasteddie313 wrote:
Stock fuel system is good to 1 bar no problem.. According to my tests it will spray like 330 HP worth of fuel, so I figure it would be good to 250HP or so conservatively..
I should have ran longer/harder on my stock fuel system, but I fell in love with the V8 fuel distributor thing, so I don't have any logs of te stock fuel system...


Internet and forum myth suggested stock CIS max'd out at 250bhp. Not found any validation of that. Curious how you calculated 330hp worth? Not a challenge, just that I'm pushing on with mine and nearing or exceeding its limits right now.

I ran 240rwhp a few weeks back, say 30bhp(?) for trans loss, so potentially 270 crank. I was really happy with that, it exceeded my expectation but fuel was running out at the top end plus my boost enrichment switch was not working, so we had it bang on AFR's in the mid but too lean at the top. Now the switch is working I can limit fuel in the mid range and turn it up for the top end. The fuel metering head as rebuilt some years ago and I assume it was stock, who knows, it was before I owned the car. I have just rebuilt another metering head to 'motorsport' spec and now flows 30% more fuel at full load. Back on the dyno again in 2 weeks to see if there's any improvement ..... I'd like to hit 300 corrected hp, so 270 at the wheels. Given my initial aim was getting over 200, then close the gap to 250 at the crank, I am now more than pleased

My concern is the stock AFM unit isn't capable in terms of efficiency more so than the fuel metering head itself.

GTS spec CIS is good for 400hp, proven by Mittelmotors race car so good luck with your build
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
CÚdric  



Joined: 27 Aug 2004
Posts: 1994
Location: Sweden

PostPosted: Sun May 17, 2020 10:08 pm    Post subject: Reply with quote

Yeah, my compressor outlet tubes was impossible to route as you did, so i had to make the longer route. Otherwise im fairly happy with it except for some pipes rubbing. It will probably develop over the years a bit.

The performance gains on the s2 is extra massive with just the intercooler, since it advances ignition timing quite a bit due to the boost temp sensors. Well worth it even at stock boost.

It seems like the system will be hard to push much beyond the 250-270 hp mark due to the leaning top end, for the midrange though there seems to be plenty available.



Here's that Facebook post, maybe i should make a big thread on here instead. I don't like Facebook for stuff like this anyway. Your install is there aswell, in the comments.

https://m.facebook.com/story/graphql_permalink/?graphql_id=UzpfSTEwMDAwMDY2OTEyNDY4MTpWSzoxNjA1NDI2MTAyOTY3NDIw
_________________
┤80 924 Turbo
Back to top
View user's profile Send private message MSN Messenger
Mike9311  



Joined: 14 Dec 2004
Posts: 878
Location: Chicago-ish

PostPosted: Mon May 18, 2020 1:23 am    Post subject: Reply with quote

Carrera RSR wrote:


Correction - USA S1 2664 4.10.........RoW S1's had 2470 6.10.

Having the 2664 and increasing boost probably saved you melting a piston as the 2470 is a heat pump before increasing the boost. More boost just sends intake temps skywards


Like I said I was ignorant of some things back then and only when the car felt good in cooler weather would I boost. I remember shortly thereafter, as the Internet came to be, the whole heat pump story. Except back then nobody really knew who had what compressor as we do now. My car pulled just fine and it wasn't until 13.5-15PSI that I felt like not much was different (I'm thinking too much heat). Made the heat pump story strange to me. It wasn't until the later 90's that I understood the 2660 - 2664 difference and the the smaller RoW 2470's. Finally making sense of the matter

It took me until recently to get 6.10 housings which I have yet to run but will this summer.

BTW - Cedric, thanks for pointing out that IAT location for IC'd S2 cars and Steve for your guidance with the WUR control
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
jacobroufa  



Joined: 18 Nov 2016
Posts: 286
Location: Rockford, IL

PostPosted: Mon May 18, 2020 2:14 am    Post subject: Reply with quote

CÚdric wrote:
Borrow or buy a wideband lambda and check the fuelling before the boost adventures. 1 or two points of AFR is the difference between running great and hole in piston territory on these cars.

Are you on the 924 turbo/gts/gtr Facebook group? I made a thread there with a massive collection of different 931 intercooler solutions that people could take a look at as inspirational. Not sure it must end up that much harder than water IC, it needs plumbing, pumps+electrical, radiator etc


I definitely will keep that in mind -- I have a friend who has a tailpipe-mounted AFR that I know I can use just about any time. Once I get ready to turn up the boost that'll be one of the first things I do.

I do not do the Facebook except to browse Marketplace; I'll have to look for that page on my wife's account. I definitely want to look more into it though, because I have an intercooler sitting on the shelf from an early 90s Saab 900, and some piping as well from a prior turbo project. I have been secretly wanting to pull that into the fold for this project, just haven't wanted to tease myself yet.
_________________
1980 Porsche 931
1981 Porsche 924 Weissach
Back to top
View user's profile Send private message
jacobroufa  



Joined: 18 Nov 2016
Posts: 286
Location: Rockford, IL

PostPosted: Mon May 18, 2020 2:35 am    Post subject: Reply with quote

Ok, I was going to try to reply to all individually but apparently more posts wound up in the thread...

Cedric -- Thank you for posting the link to that Facebook page. That gives me lots to think about, and makes my little Saab intercooler seem like a realistic solution.

Your engine bay is OUTRAGEOUS. How does it look so clean and perfectly stock?!

Eddie -- You've got a lot going on there man, I really appreciate seeing your routing in that FB post Cedric linked. I feel like I saw that at some point on the board as well, but it was good to be reminded of it. So did you pull apart the turbo in the middle and offset the compressor housing 180░ or something? I will have to look more for where you detail your work.

My biggest concern with doing anything with an intercooler is it seems like most solutions end up needing SOME fabrication (which I am not equipped to do) and so they seem relatively unobtainable. Making a simple bent metal bracket with a couple holes though is doable. I just jump in my my head to installs like Steve's -- that's the dream anyway.. But well outside my reach as my current skillset allows. I just don't want something janky looking. I really prefer the stock/OEM look and I want to be careful about what I do to the car. So that means no modification of hard to get parts like charge tube et al...

As to how much money and time I want to spend? I feel like if I can just crank the boost up a bit, my butt dyno will be super happy. If I want to go stupid fast I will hop in one of the daily drivers -- modern cars are absurdly equipped. Even my decade old A6 is pushing 300hp with a supercharged V6... With a vintage car like the 931 I think it makes less sense to have too much power because the real joys are in the minutae of the driving experience not raw power... It is good to know though that there are a few folks on the board who have well surpassed what my goals are.

Steve & Mike -- So with an S1 I have the 2664 wheel and a 4.10 size housing -- the 2470 wheel is a different shape and 6.10 is a bigger housing? Does that mean it has capacity to build more boost later on? I have read a bit about the different housing/wheel combinations, and understand very little about what is interchangeable and what the effects of each will be. Is there an ideal combination? It seems like the 2664 are not available and so I should just hang on to mine.. But there's also e.g. K26 vs K27 -- so many different parts and variations that I see people using. What is incentive to change over to a different housing or compressor wheel and how will I know when I hit the point where I need to? To pile on here, what is the big difference between 924 and 944 turbos -- ours are just oil cooled and the 951 got a watercooled turbo? Does this upgrade make sense at some point?

I know these questions are probably way more disparate than I am making them out to be, but I grouped them all together because that's the current pithy state of my understanding...
_________________
1980 Porsche 931
1981 Porsche 924 Weissach
Back to top
View user's profile Send private message
jacobroufa  



Joined: 18 Nov 2016
Posts: 286
Location: Rockford, IL

PostPosted: Mon May 18, 2020 3:04 am    Post subject: Reply with quote

Eddie what's the deal with your air box? Was that a necessary modification because of your V8 fuel distributor?
_________________
1980 Porsche 931
1981 Porsche 924 Weissach
Back to top
View user's profile Send private message
jacobroufa  



Joined: 18 Nov 2016
Posts: 286
Location: Rockford, IL

PostPosted: Mon May 18, 2020 3:15 am    Post subject: Reply with quote

Ok, Cedric & Eddie... What is your compressor housing changed out to in order to get it to re-index properly and face the outlet downward? And how are you now managing extra pressure build-up? It looks like you have added a BOV to the upper charge tube, Eddie, is that correct? I have an incredible amount to read and try to understand here, but I gather that modification of turning the housing cannot be done with our stock compressor housing because of the built in recirculation valve.

Speaking of recirc/blowoff this thought just occurred to me. One of my favorite things about a previous older turbocharged car I had (1992 Saab 9000 Griffin Ed) was the flutter noise that happened after spooling. With the 931 all I get is the spool noise. That's cool, don't get me wrong, I am just curious why I don't get the fluttering too -- is that due to a different pressure management setup on that car?
_________________
1980 Porsche 931
1981 Porsche 924 Weissach
Back to top
View user's profile Send private message
ideola  



Joined: 01 Oct 2004
Posts: 15506
Location: Woodstock IL

PostPosted: Mon May 18, 2020 4:43 am    Post subject: Reply with quote

The S1 has the integral recirc valve in the cold side housing. To index it differently, you need a non-stock (non-931) cold side housing. The recirc valve is required (as opposed to blow off valve) to keep the metered air within the CIS system. It also muffles some of the usually turbo sounds you might be used to.

I own the rights to the TMIC and TMCC. I can and will process addtional orders on demand. Just let me know when you're ready.
_________________
75 Fiat X1/9 | 80 US 928 | 80 US 931 '941' | 78 D-Prod Replica | 78 Poli-Form
Back to top
View user's profile Send private message
jacobroufa  



Joined: 18 Nov 2016
Posts: 286
Location: Rockford, IL

PostPosted: Mon May 18, 2020 4:58 am    Post subject: Reply with quote

ideola wrote:
The S1 has the integral recirc valve in the cold side housing. To index it differently, you need a non-stock (non-931) cold side housing. The recirc valve is required (as opposed to blow off valve) to keep the metered air within the CIS system. It also muffles some of the usually turbo sounds you might be used to.


Nice to know. I have a turbocharger on the shelf from an VW/Audi 4 cylinder (from the same project as that Saab intercooler). I will have to pull a part number and see if the cold side is interchangeable.

ideola wrote:
I own the rights to the TMIC and TMCC. I can and will process addtional orders on demand. Just let me know when you're ready.


That's awesome to hear about the intercooler, Dan. I thought you did a group buy in order to even be able to manufacture them at all; was it for cost control then? What would a single unit run me?
_________________
1980 Porsche 931
1981 Porsche 924 Weissach
Back to top
View user's profile Send private message
jacobroufa  



Joined: 18 Nov 2016
Posts: 286
Location: Rockford, IL

PostPosted: Mon May 18, 2020 5:51 am    Post subject: Reply with quote

Oh here is the rabbit hole...

So Mike! Can I twist your arm for a custom part or two? Once I'm ready, I mean -- it'll be awhile before I can swing the Ideola intercooler and everything necessary to install -- I will specifically be on the lookout for the lower charge tube to intercooler elbow that you made:

http://www.924board.org/viewtopic.php?p=391740#391740

---

I can't stop reading about all the possibilities with this car. My head is reeling.
_________________
1980 Porsche 931
1981 Porsche 924 Weissach
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Discussion All times are GMT + 10 Hours
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8, 9  Next
Page 5 of 9

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group