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

Intake Manifold
Goto page 1, 2  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions
View previous topic :: View next topic  
Author Message
DZGunner  



Joined: 18 Nov 2014
Posts: 166
Location: Great white north

PostPosted: Sat Mar 21, 2020 4:57 pm    Post subject: Intake Manifold Reply with quote

I'll try to be as brief as possible.

I have a 1979 924 NA North American model.
-Will a Carrera GT Intake fit this car.



Also I understand there is an S1 and S2 intake setup on these cars.
-What are the year ranges that had these intakes
-If they are similar, then by just looking at one of each setup, what
differences can be seen or how can i visually tell them apart?

Thanks in advance guys
_________________
1980 931 S (The project)
1979 924 (Daily driver)
1979 924 (Parts)
1977 924 (Pop's)
1977 924 (Parts)
Back to top
View user's profile Send private message
Fasteddie313  



Joined: 29 Sep 2013
Posts: 1922
Location: MI

PostPosted: Sun Mar 22, 2020 10:16 am    Post subject: Reply with quote

I think the turbo head bolts up differently than an NA head, to the intake manifold..
_________________
80 Turbo - Slightly Modified
Back to top
View user's profile Send private message Yahoo Messenger
DZGunner  



Joined: 18 Nov 2014
Posts: 166
Location: Great white north

PostPosted: Sun Mar 22, 2020 11:15 am    Post subject: Reply with quote

Are you referring to S1 and S2 intakes? or the GTS compatibility, or both?
_________________
1980 931 S (The project)
1979 924 (Daily driver)
1979 924 (Parts)
1977 924 (Pop's)
1977 924 (Parts)
Back to top
View user's profile Send private message
peterld  



Joined: 10 Dec 2006
Posts: 771
Location: Noosa Heads QLD Australia

PostPosted: Sun Mar 22, 2020 4:43 pm    Post subject: Reply with quote

The Carrera GT intake manifold is similar to the S2 Turbo, ie. round port inlet, from year '81 onwards.
The S1 intake ('79-'80) bolts to the head identically, but has an oval port intake. The throttle bodies are consequently different.
_________________
80/81 932/8 ROW
Back to top
View user's profile Send private message Send e-mail
morghen  



Joined: 21 Jan 2005
Posts: 8165
Location: Romania

PostPosted: Sun Mar 22, 2020 4:48 pm    Post subject: Re: Intake Manifold Reply with quote

DZGunner wrote:
I'll try to be as brief as possible.

I have a 1979 924 NA North American model.
-Will a Carrera GT Intake fit this car.



No and there is no reason to have a turbocharged manifold on a NA car.
Intake boots wont fit, accelerator cable wont fit, no vacuum port for your ignition advance, intake ports are much smaller on the NA and that causes massive turbulence when paired with a larger diameter size ports of the intake.
Also the GT manifold has more signal ports that serve the turbo system..there is nothing to fit in those ports on the NA car.
_________________
Ruby-sh 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
DZGunner  



Joined: 18 Nov 2014
Posts: 166
Location: Great white north

PostPosted: Sun Mar 22, 2020 5:23 pm    Post subject: Reply with quote

Thanks guys. So I guess to get a little more specific of why I ask...

I recently ordered the VEMS EFI kit from "Raceboy" (I believe is what he's called on here) and I'm looking for a way to get a throttle body with a TPS mount already integrated on it. Now if I had a circular port for the throttle body i could have just about any throttle body with TPS mount I want, however I'm stuck with the oval throttle for now.

So timing advance, intake boots, and throttle cables aside, would it actually mount to the NA head. The ports being different sizes could be a real problem, but I'm just wondering if it would bolt straight up, or lets even say an S2 manifold. The goal here being to fit a throttle body with TPS mount.

If not these, then I'm really not sure what kind of janky modifications to the oval throttle I'm going to have to do. lol
_________________
1980 931 S (The project)
1979 924 (Daily driver)
1979 924 (Parts)
1977 924 (Pop's)
1977 924 (Parts)
Back to top
View user's profile Send private message
DZGunner  



Joined: 18 Nov 2014
Posts: 166
Location: Great white north

PostPosted: Sun Mar 22, 2020 5:27 pm    Post subject: Reply with quote

Also I'd like to note that I do realize how ridiculous that would be to have a GTS intake on an NA car, I'm just looking at every single possible option.
_________________
1980 931 S (The project)
1979 924 (Daily driver)
1979 924 (Parts)
1977 924 (Pop's)
1977 924 (Parts)
Back to top
View user's profile Send private message
peterld  



Joined: 10 Dec 2006
Posts: 771
Location: Noosa Heads QLD Australia

PostPosted: Sun Mar 22, 2020 6:23 pm    Post subject: Reply with quote

Port match an S2 Turbo manifold to your NA head and you'll be good to go with a round port opening inlet manifold.
_________________
80/81 932/8 ROW
Back to top
View user's profile Send private message Send e-mail
Raize  



Joined: 18 Sep 2013
Posts: 131
Location: Scotland

PostPosted: Sun Mar 22, 2020 8:00 pm    Post subject: Reply with quote

A lot of 80s VW and Audi throttle bodies bolt right up and some may have TPS although from my research the TPS is a very expensive replacement part and usually broken.
_________________
1981 N/A daily driver with:
Headlight relays. Vacuum gauge. Cold start switch. Kill switch. Ported cylinder head, intake and 944 exhaust. Brake booster venturi delete. 53/35mm throttle body. M62 supercharger mounted but not connected
Back to top
View user's profile Send private message
morghen  



Joined: 21 Jan 2005
Posts: 8165
Location: Romania

PostPosted: Sun Mar 22, 2020 9:09 pm    Post subject: Reply with quote

The Na head flows poorly and the effort to adapt a turbo or gts intake would be in vain.
If i were you id just work on bolting up a different TB on the NA intake and be done with it.
Im sure that an adapter plate is cheaper and easier to make than to swap over a more expensive manifold and work to mitigate the differences.

I heard some Subaru TBs are bolt on and they have the right tps for the vems.
_________________
Ruby-sh 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
MikeJinCO  



Joined: 08 Jun 2010
Posts: 900
Location: Maysville, Colorado

PostPosted: Sun Mar 22, 2020 10:45 pm    Post subject: Reply with quote

The bolt pattern is different between the NA and 931 heads. The bottom bolts are the same, but the top ones spread higher and toward the back. I managed to make a Weber carb manifold fit the 931 head but it is much simpler than any turbo manifold. The ports match up pretty well, although the 931 ports are bit larger and required some grinding on the manifold to match.
_________________
Mike
Poco a Poco, #033 '78 Vintage racer, SCCA Dp-81
'77 924
cricketdesigns.com
Back to top
View user's profile Send private message Visit poster's website
DZGunner  



Joined: 18 Nov 2014
Posts: 166
Location: Great white north

PostPosted: Mon Mar 23, 2020 3:13 am    Post subject: Reply with quote

How about... what if I found a 931 head with s2 intake already on it, it would match the block im sure, but would the exhaust manifold have the same pattern? Would valve clearance be ok? and would it run alright without a turbo?

I had been looking at how I could make an adapter plate long before I came to the board to consult you guys, and the main problem is space, which is why I'm looking into all these other possible solutions.

Also I think I found the Subaru TB someone had mentioned, but not only was it used on the s2 intake, but it was on a turbo model that may or may not have had the s1 intake on it before. It doesnt really say that, but it's sort of implied the way he brings up that it was used and that the year of the car may have been 1980. I'm not really digging all this "may have" and "could be"

http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/1032819-porsche-924-racecar-build-thread-aan-conversion.html
_________________
1980 931 S (The project)
1979 924 (Daily driver)
1979 924 (Parts)
1977 924 (Pop's)
1977 924 (Parts)
Back to top
View user's profile Send private message
MikeJinCO  



Joined: 08 Jun 2010
Posts: 900
Location: Maysville, Colorado

PostPosted: Mon Mar 23, 2020 6:21 am    Post subject: Reply with quote

No, the NA exhaust manifold will not bolt up to a 931 head, again the bolt spacing is larger. Also due to the combustion chamber in the head you would loose the compression ratio back to probably 6, new pistons would be needed. Some years ago there was a Weber throttle body but I can't find any more than that. It Probably came from Redline Weber in the US. I'd ask Raceboy what to do.
_________________
Mike
Poco a Poco, #033 '78 Vintage racer, SCCA Dp-81
'77 924
cricketdesigns.com
Back to top
View user's profile Send private message Visit poster's website
morghen  



Joined: 21 Jan 2005
Posts: 8165
Location: Romania

PostPosted: Mon Mar 23, 2020 6:41 am    Post subject: Reply with quote

S2 head + NA pistons = nothing...you cant use the turbo head unless you also change the pistons. Also the exhaust manifold wont fit anymore.

Just get an adapter plate made for the TB you want to use on your NA manifold.
_________________
Ruby-sh 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
DZGunner  



Joined: 18 Nov 2014
Posts: 166
Location: Great white north

PostPosted: Mon Mar 23, 2020 7:54 am    Post subject: Reply with quote

He's been busy lately, I shot him a message a while ago but haven't heard anything yet, so I'm brainstorming solutions if he doesn't have one for me. Looks like I'm gonna have to start making a plate.

I did manage to dig this modification up from a guy who SC his 924. I'm not entirely sure if he just removed the bottom spring, if that spring was needed, or what he did to make this work... Scroll about 2/3 down the page and you'll see it.

http://www.924board.org/viewtopic.php?t=33291&postdays=0&postorder=asc&start=195
_________________
1980 931 S (The project)
1979 924 (Daily driver)
1979 924 (Parts)
1977 924 (Pop's)
1977 924 (Parts)
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions All times are GMT + 10 Hours
Goto page 1, 2  Next
Page 1 of 2

 
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