116 replies to this topic

[Bill USN-1]

Dont you want about 10 at idle?
My car idles at about 35kpa with 100kpa being ambient pressure (engine not running), which will be what (or very close).

35 at idle is pretty normal on my stock motors. With a small cam my V8 idles about mid 40's.

Timing is always a source of debate...
Right now the table is set up to represent manifold vacuum to the vacuum advance vice ported vacuum.

Using ported vacuum the source is above the throttle plate so as the throttle is opened the vacuum increases.
If the throttle is opened wide there will be no vacuum.

For manifold vacuum you have the highest vacuum draw at lower throttle settings.
Again as you stab the throttle open the vacuum will drop to nothing and you operate off mechanical advance only.

Boats and race engines do not utilize a vacuum advance simply because of the operating range od the motor. There is no light load conditions where the vacuum advance would come into play.

Both forms of vacuum advance are used on various motors.
Supposedly the manifold vacuum with the higher timing at idle is suppose to be better for emissions.

I grew up running ported vacuum so what I normally do is just just take the entire timing table from 0 to 50 map and from 0 to 800 rpm and set it to 15°.

As I noted, these tables were created strickly from the rpm and vacuum data listed in the 123 distr specs.
As I refine the actual tables I will use I will post them up.

If anyone has any other distr specs from carb models, post them up and I can build some averages and move vacuum timing around for a different look.

[Bill USN-1]

If I remove the vacuum advance except from 5-10"hg then this is what the basic table looks like.
Still not quite there sinc it does not take into account the high vacuum conditions on light load cruise or decel.

10.0 10.0 10.0 10.0 10.0 10.0 10.0 23.5 21.5 18.0 14.0 10.5 10.5 10.0 10.0
10.0 10.0 10.0 10.0 10.0 10.0 10.0 23.5 21.5 18.0 14.0 10.5 10.5 10.0 10.0
10.0 10.0 10.0 10.0 10.0 10.0 10.0 23.5 21.5 18.0 14.0 10.5 10.5 10.0 10.0
10.0 10.0 10.0 10.0 10.0 10.0 10.0 23.5 21.5 18.0 14.0 10.5 10.5 10.0 10.0
12.0 12.0 12.0 12.0 12.0 12.0 12.0 25.5 23.5 20.0 16.0 12.5 12.5 12.0 12.0
14.0 14.0 14.0 14.0 14.0 14.0 14.0 27.5 25.5 22.0 18.0 14.5 14.5 14.0 14.0
16.0 16.0 16.0 16.0 16.0 16.0 16.0 29.5 27.5 24.0 20.0 16.5 16.5 16.0 16.0
18.0 18.0 18.0 18.0 18.0 18.0 18.0 31.5 29.5 26.0 22.0 18.5 18.5 18.0 18.0
19.3 19.3 19.3 19.3 19.3 19.3 19.3 32.8 30.8 27.3 23.3 19.8 19.8 19.3 19.3
21.8 21.8 21.8 21.8 21.8 21.8 21.8 35.3 33.3 29.8 25.8 22.3 22.3 21.8 21.8
24.3 24.3 24.3 24.3 24.3 24.3 24.3 37.8 35.8 32.3 28.3 24.8 24.8 24.3 24.3
26.8 26.8 26.8 26.8 26.8 26.8 26.8 40.3 38.3 34.8 30.8 27.3 27.3 26.8 26.8
29.3 29.3 29.3 29.3 29.3 29.3 29.3 42.8 40.8 37.3 33.3 29.8 29.8 29.3 29.3
31.0 31.0 31.0 31.0 31.0 31.0 31.0 44.5 42.5 39.0 35.0 31.5 31.5 31.0 31.0

Edited by Bill USN-1, 26 January 2007 - 02:21 PM.

[Boab]

Fascinating and quite frankly, I'm bamboozeled, but I love the wee shake of the hips when it first fires up. Its the kind of thing I do when something goes right.

[Bill USN-1]

Fascinating and quite frankly, I'm bamboozeled, but I love the wee shake of the hips when it first fires up. Its the kind of thing I do when something goes right.

I had to edit the video for the G rated version.
I knew a lot of 16yo kids would be on here!!!

[Sprocket]

As requested, Before and After pictures.

You'll have to suffer just the before pictures, as i've just sent it to Slark Race Engineering for the mods so obviously not got it back yet. LOL

How you getting on with yours???

Edited by Mini Sprocket, 31 January 2007 - 10:59 PM.

[Bill USN-1]

I already got one of those!!
I want to see the good stuff!!

Are you planning to get rid of the little diverter at the end of the runners?

I was contemplating that but I have to believe they added it for a reason with the siamesed port configuration.

I was also looking at just using some 2" mandrel bent exhaust pipe for the manifold. That would give maximum ID.
But I also thought that the smaller runner may be better for velocity.....too many what if and variables!!


As for me I have installed and removed the engine already just waiting for the postman to deliver the connectors for the throttle body!!
That's why I decided to just go ahead and modify the flywheel and backing plate while I wait.

I have to do something on the car to stay busy!!
I guess i should pull the front calipers and reseal them. I picked them up used.

[Sprocket]

The early manifolds do not have that flash, it was introduced around 94. Its, as you say, to try and even out the charge distribution in the siamese port.

It will be gone, and the port will be the same diameter as a standard injection gasket, BIG, and will match the ports on the head. That with the bigger throttle is all that can be done to improve air flow with the SPi set up.

It was funny realy, i spoke to a bloke that already has a modified manifold, see if he wanted to sell it to me. He wanted to keep it, fair enough. He pointed me to Slark who modified his. He also said that he has a new manifold if i wanted to buy that and then send it of while keeping the mini on the road till i swapped the manifold out. I asked the price. He said £150. I said F$&k off!!. LOL, managed to pick up an almost new, hardly used manifold at Bingly last Sunday for £30 (the one above)

The mods are only costing £50+VAT. I think that chap lives in another world where he thinks people will pay £500 for a complete new manifold when Minisport are advertising them for around £300. Most people would fit a carb, LOL

Had to giggle

[Bill USN-1]

I would have told him the same.

I am amazed at some of the prices. I wonder how people really afford those things for a hobby.

But it's still better then spending it on drugs or booze!!

That's what I tell the wife...every night in the garage is 1 less night out on the town!!

[Bill USN-1]

I only got a couple of my parts in so work is progressing slowly.
I am running a LCB and I want the O2 to monitor all cylinders so i am mounting the O2 in the collector. (Y pipe)

I will also be using a Wideband O2 during tuning so I will add and additional bung and just keep a plug in it until needed.

There are ready made O2 bungs available and bungs with plugs.
What I have been doing for years is using the 18mm anti foulers for spark plugs and just cutting to length.
They are very cheap and work great.

Here are some pics of my install.
Ignore the welding...I ran out of gas on my mig right after i started and had to clean up my welds with the grinder!!

[Nial]

Ignore the welding...I ran out of gas on my mig right after i started and had to clean up my welds with the grinder!!

Good tip about the anti-foul plugs.

Your welds look lovely but is there room for the O2 sensor to stick up vertically when the
exhaust's installed or will you have a cut-out in the exhaust tunnel?


[Edit] Just noticed, that won't be vertical in the car will it? Have you mounted it slightly down hill? Most
of the placement guides I've seen suggest mounting the sensors from 10:00 to 2:00 [/Edit]


Nial.

Edited by Nial, 12 February 2007 - 05:40 PM.

[Bill USN-1]

I tried to get them close to 3 o'clock just to avoid interference with the body.
I don't think the sensor will get moisture at that angle but if it does...their cheap enough to replace!!

[Sprocket]

Ok so here we have a modified SPi inlet manifold. There has only been general light smoothing at the throttle body end due to that being a water jacket with the coolant passing through it. The port end has been opened out and smoothed in right back to where it first turns into the runner. Looking at them side by side there is a massive increase in crossectional area of the runner. So should improve things some what!

[Bill USN-1]

Looking good!!!

I just got the parts I needed in today.
Only took a month to get here from the UK.

But I now have all the connectors for the TB.
I got my new clutch bolts.
And I went with the captive nut motor mounts. I was a little sceptical when I saw them and wondered if the thread insert would hold.
I really thought about adding a spot weld to the edge of them.

Well I was right.
I dropped the motor back in tonight and the last insert started to turn on me.
Guess i should have welded them!!


Then I drop the LCB in and find out the Y hits the floor pan.
So I guess I get to knotch the pipes and bend them down to clear the floor then weld them back up.

How far can you adjust the top of the motor with the torque rod without affecting anything else?
Is it just firewall clearance or do the pot joints come into play?

[Major Burkenshaw]

What tool or tools did you use to remove and polish the metal? Having seen yours, i might do the same to mine B)

[Sprocket]

All later 92 onwards cars had the engine 12mm further forward as per the Autos. The engine tie bar is the same as the Auto and the rod change rods are again 12mm longer

Why not re drill the engine mount holes in the subframe 12mm forward and the two rod change mounts again 12mm forward on the tunnel, then use an Auto engine tie bar?

It might give you the clearance you need???