Opel GT Forum banner

1 - 20 of 208 Posts

·
Member
Joined
·
648 Posts
Discussion Starter · #1 ·
Opel-ites,

While sitting around trying to think about how to spend money I don't really have...I started thinking about side drafts, and came up with a few questions. Several manifolds have appeared on e-bay resently. I know in the past it's been discussed by Rally Bob about the different flow rates for the different brands and lengths of dual manifolds. But I don't remember anyone really getting in depth about useing the single side draft, so here's my questions:

1) If running a single side draft, what size carb? I know most people run the 40's for the dual, but would you need the 45 for the single? (Modified engine)

2) Is the single SD that much of a let down from the dual setup?

3) is the single SD a significant boost over running the 38 down draft on a ported manifold? (to be worth the money spent)

I'm thinking single for a few reasons: no cutting or removing the heater required, less linkage, and less tuning. However, I have a great running 38 that has been tuned and I don't want to change it unless I get a noticeable jump in HP.
Ideas?

James

70 GT 2.0 11:1 Venolia and TGSI head
 

·
1450 Seeker...
Joined
·
613 Posts
I need to preface my comments that I have no experience outside of my current 32/36, but have been doing my homework on Opel intake setups.

Now, my impression was that the upgrade path would be
Single 32/36
Single 38
dual SD 40's
dual SD 45's
moving up the scale as you increased displacement and peak RPM.

For the single side draft, I would not expect a significant ROI (return on investment) accounting for the purchasing of a new single side draft manifold and carb and corresponding tuning/fitment/fabrication, especially where you have already invested time and $$$ in a 38.

PS. what cam and valve sizes do you have in that TGSI head?
 

·
Super Moderator
Joined
·
5,298 Posts
Ssd

madhatterpdc said:
I need to preface my comments that I have no experience outside of my current 32/36, but have been doing my homework on Opel intake setups.

Now, my impression was that the upgrade path would be
Single 32/36
Single 38
dual SD 40's
dual SD 45's
moving up the scale as you increased displacement and peak RPM.

For the single side draft, I would not expect a significant ROI (return on investment) accounting for the purchasing of a new single side draft manifold and carb and corresponding tuning/fitment/fabrication, especially where you have already invested time and $$$ in a 38.

PS. what cam and valve sizes do you have in that TGSI head?
SSD is the best SINGLE 2-BARREL CARB installation on our Opel engines . . . BAR NONE!!!!

Check mine here in case you don't remember:

Otto's SSD in my '72 GT

:eek:
 

·
1450 Seeker...
Joined
·
613 Posts
Okay, first thing, no need to yell.

Second, I prefaced my comment with the fact that I only have first-hand experience with the 32/36. I offered my comments under the context of what my impressions are of the respective setups based on my research and planning for my own engine.

Third, I would personally have a hard time justifying the expense and tuning time of moving from a tuned 38 to any other setup (SSD, dsd or what have you), regardless of popular opinion, given the versatility of the 38 for most street engines.

Fourth, I haven't seen too many SSD manifolds. If someone were to find a manifold at a decent price and a gently used and rebuildable Weber sidedraft for the right price, and is willing to sacrifice a couple of afternoons tuning the carb, then go for it.


I never meant to detract from the viability of a SSD setup.
 

·
Banned
Joined
·
3,842 Posts
I couldn't help noticing the intakes for sale on ebay. The first single sold for 105 and the other is still out there. The steinmetz twin set went for 109. If they are selling for about the same price you would be looking at the price of a carb difference. There is the issue of the heater box, I have more heat now than stock. That is after the twins were installed. I would keep that in mind as the potential for power out of the twin carbs is alot better than any single. I guess it all depends on your budget and what you want in the end. I also agree with both tekanaar and madhatter. The sidedraft weber is a sweet carb and by itself would be great on any car, but bang for the buck would probably be the DGAS. I will also admit to being biased, I think the 1.9 should have came stock with twin sidedrafts. I just corrected a design flaw.
 

·
PrOpeller
Joined
·
707 Posts
Also should note that the two recent manifolds on eBay both do not incorporate a shared plenum design like the Steinmetz manifold which Otto's using. Unsure how that will affect performance and tuning characteristics.
 

·
Member
Joined
·
648 Posts
Discussion Starter · #7 ·
Otto,

I do remember seeing your picture. What a neat job you did!
Could you tell us what size carb and what venturi you are using?

ThanX,
Jc
 

·
Super Moderator
Joined
·
5,885 Posts
Hey, Otto wasn't YELLING! He was just being DEFINITE :) Like we have never seen THAT before :D

The first single sold for 105
http://cgi.ebay.com/ebaymotors/ws/e...&category=36474&sspagename=STRK:MEADW:IT&rd=1

Yea, that Pace Setter SSD manifold was 1 minute 10 seconds away from being MINE! Well, I just thought I would "stink bid" it at $100.05. Twenty hours later, I was still high bidder, with only two minutes to go. CRAP! I had JUST bought a brand new 38 DGAS with that cool finned aluminum adaptor from a guy in Surrey B.C., so what the HECK was I doing bidding on a SSD manifold that I didn't need, and had the wrong carb for. Then I noticed that the SSD manifold seller also had a Weber 40 DCOE side draft for sale, with only three minutes left. JUST as I was about to bid on the DCOE, I was outbid on the Pace Setter. I just STARED at the screen, trying to decide if this was fate, or should I trump in. Then I thought AGAIN about the brand new DGAS in my garage, and the fact that I have a '75 EFI if I really wanted, not to mention a BUNCH of other projects that seem to be keeping this GT "restoration" from EVER being completed.

So I made the WRONG choice, and didn't bid. It was like watching a best friend die before my eyes, as the auction ended. CRAP! What a TERRIBLE feeling! Anyways...

I still feel terrible. I really wanted that SSD manifold. I am with Otto, that is the BEST street setup available. Straight rams, excellent throttle response, terrific tune-ability, looks sharp, less calories... Ok, I am getting carried away. But if I can talk that guy selling that balanced SSD manifold to sell it to me in Canada (only in the USA, he says. Pity!), don't get in my way!
 

·
Banned
Joined
·
3,842 Posts
I happened to "tune in to ebay" just as that happened. You had it, I hit refresh, and it was over. I liked the design better than the one up for sale now. It seemed straighter from carb side to intake. I don't remember was the intake venturi joined after the carb attaching plate like the one for sale now?

By the way did you look at that final bellypan price?
 

·
Super Moderator
Joined
·
5,298 Posts
SSD 40 Jetting . . .

N61WP said:
Otto,

I do remember seeing your picture. What a neat job you did!
Could you tell us what size carb and what venturi you are using?

ThanX,
Jc
I'll do you one better.

DellOrto DHLA40 jetting (what I'm using):

-1 AVs (largest), 34 chokes, 75 idles, 55 pumps, 178 mains, 200 airs.

Equivalent Weber 40DCOE jetting:

5.0 AVs, 34 chokes, 65F9 idles, 55 pumps, 155 mains, 185 airs, F16 E-tubes.

ALL my little secrets revealed . . . convinced yet?
:D
 
  • Like
Reactions: Knorm65 and m610

·
Super Moderator
Joined
·
5,298 Posts
Pace Setter SSD manifold

kwilford said:
Hey, Otto wasn't YELLING! He was just being DEFINITE :) Like we have never seen THAT before :D

http://cgi.ebay.com/ebaymotors/ws/e...&category=36474&sspagename=STRK:MEADW:IT&rd=1


Yea, that Pace Setter SSD manifold was 1 minute 10 seconds away from being MINE! . . .

. . . I still feel terrible. I really wanted that SSD manifold. I am with Otto, that is the BEST street setup available. Straight rams, excellent throttle response, terrific tune-ability, looks sharp, less calories... Ok, I am getting carried away. But if I can talk that guy selling that balanced SSD manifold to sell it to me in Canada (only in the USA, he says. Pity!), don't get in my way!
Went to look at that SSD manifold and hope you weren't planning on using it in a GT . . . WON'T FIT!!!

Proof?!!!:

:(
 

·
Super Moderator
Joined
·
5,298 Posts
Re: SSD manifold use in a GT

tekenaar said:
Went to look at that SSD manifold and hope you weren't planning on using it in a GT . . . WON'T FIT!!!

Proof?!!!:

:(


Can't even use the Cannon type anti-vibration mounts in a GT! TOO THICK!!


Further Proof:
 

·
Super Moderator
Joined
·
5,298 Posts
Re: SSD airbox in a GT . . . yea!!!!

tekenaar said:
Can't even use the Cannon type anti-vibration mounts in a GT. Further Proof:
AND, for those even thinking about an SSD in a GT, here's something that I KNOW will work: :D
 

·
Super Moderator
Joined
·
5,298 Posts
Re: Re: SSD manifold use in a GT

tekenaar said:
Can't even use the Cannon type anti-vibration mounts in a GT! TOO THICK!!
For those considering a non-GT SSD installation, I've got that pictured set of those Cannon AV mounts (mounted once and then never used) that I'd let go pretty reasonably. email me privately.
 

·
1450 Seeker...
Joined
·
613 Posts
Here is a cross-reference question for the masses...

What, if any, intake manifolds can cross-reference with the CIH intake port pattern? I see a lot of VW and MG manifolds on ebay, but very few for the Opel.
 

·
Super Moderator
Joined
·
5,298 Posts
CIH Intakes and such . . .

madhatterpdc said:
Here is a cross-reference question for the masses...

What, if any, intake manifolds can cross-reference with the CIH intake port pattern? I see a lot of VW and MG manifolds on ebay, but very few for the Opel.


In a word, NONE!
The CIH is a non-crossflow head and intake and exhaust share the four inner mounting bolts, making it especially difficult . . . as in, not even any other Opel engine's intake will fit it. Even then, these fit ONLY the early CIH heads (1.5-2.0), not even the 2.2/2.4 CIH heads! :(

Not only do the mounting bolt "holes" have to be accurately located, but the flange thickness has to be exactly the same as the exhaust manifold because of those shared mounting bolts. Improper flange thickness is the primary reason why there were never any very good headers made for the CIH . . . typically they just didn't seal well because of too thin flanges. :(
 

·
Super Moderator
Joined
·
5,298 Posts
nobody said:
Ok I hear what you are saying. SSD will not work in a GT. Then you show pics of it installed with short air horns and an air box. Unless you are skipping something. It looks like you could have put the air cleaner on in the first pic and kept the antivibration mounts. Unless you are dead set on a big tall boxed in air filter. When you use the side draft or side drafts the idea is the straightest shot in for better air flow and less turbulence. Again the longer the air horns the better but when you get down almost to the edge of the carb they are pretty much useless. The point you were trying to make didn't come across. Was there a mount issue? A length problem? Air cleaner? What made you decide SSD wouldn't work in a GT?
Actually, you just misinterpreted what I was saying. Should've been a bit clearer perhaps. Here's the deal . . .

I was just warning everyone that the room to install an SSD with a proper cold flow airbox in a GT is EXTREMELY TIGHT!! It CAN be done, but you ONLY have enough room to use a very short SSD manifold in a GT.

I fabricated the smallest possible airbox to still maintain enough "head space" for sufficient airflow into the carb AND allow it to clear the heater box. TRUST ME, that extra 3/16" of the AV mounts allowed the air box to fit with a tiny bit of clearance. WITH the AV mounts, the airbox absolutely would not fit without heater box interference.

You are correct about longer airhorns providing better flow . . . but primarily at higher RPM. There's not much to be gained over the short ones below 5500 however. The main benefit at lower RPM is "air straightening" and you get THAT with both.

Personal experience and testing tends to refute your assessment of my "shorty" airhorns as "useless". Since I had to wait some time for the airhorns to arrive from England, I had a good chance to check both 0-60 accelleration times and steady speed mileage of my GT without them.

My 0-60 times were improved by an average of .15 seconds after installing them. My 75MPH steady speed mileage also improved by about .8 MPG. THAT was somewhat unexpected . . . I had thought mileage would decrease slightly.
;)
 

·
Banned
Joined
·
3,842 Posts
Sorry I didn't mean any disrespect. The point of it being fitted for a cold flow box must have eluded me. I like the design potential of the ssd. Just too bad more of them weren't made. I probably would have gone to a single first instead of going from solex to twins. Then again like the Coors commercials who doesn't like twins.
 

·
Old Opeler
Joined
·
5,564 Posts
X-reference

madhatterpdc said:
Here is a cross-reference question for the masses...

What, if any, intake manifolds can cross-reference with the CIH intake port pattern? I see a lot of VW and MG manifolds on ebay, but very few for the Opel.
Vauxhall Calton & Fontera plus Holden Torana all use the CIH "Opel" engine. The Fontera right up to the mid 1990's.

Manglotesi from UK make a single and a twin side draft manifold.
Bit long for the GT though.

There are occassional manifolds on UK EBay but most Brits seem to be very reluctant to export .... or use Paypal. They do understand some of the English language though - which makes them a bit easier to pursuade than the Germans!
 
1 - 20 of 208 Posts
Top