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> 914 and 550, both T4, One Cold Starts, the Other Doesn't, Why?
Tastyplacement
post Jun 24 2017, 08:11 PM
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This is baffling to me. I have two type 4 cars, both have 914 motors and have a lot off commonality to them. My 914 starts cold no problem. My 550 replica is a total hassle to start cold.

The 914 which cold starts very easily:
-1.8 liter motor
-twin IDF 40 with no choke and no cold start circuit
Main Jets are 115
Idle Jets are 55
carbs were recently completely rebuilt
-Pertronix Ingnitor 1 points replacement

The 550 replica:
-2.3 liter motor
Main jets are 155
Idle jets are 65
carbs seem great, but haven't been thoroughly cleaned recently
-twin IDF 44 with no choke and no cold start circuit
-Pertronix Ignitor 3 points replacement

The 914, I pump the pedal once, car starts every time and is immediately steady. The 550, I have to pump the pedal 4 or 5 times and It'll fire quickly and die quickly. Once I do this a few times it'll run if I keep it at about 2000rpm by feathering throttle. Once it is warm, it's awesome.
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Rand
post Jun 24 2017, 08:13 PM
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I've never had luck with carbs and no choke being a friendly cold start combo. Surprised the 914 works so well. Does it run really rich after warm up?
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jvmarino
post Jun 24 2017, 08:21 PM
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Maybe the spark plugs. My carb'd 914 2.0 was tough when cold and I recently installed new plugs (after 20 years on the Platinum plugs I put in when I did a rebuild), and the cold idle is much smoother. The old plugs still ran great when the car warmed up.
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thelogo
post Jun 24 2017, 08:28 PM
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I would think the more performance oriented
Your engine is

The less flexibility it will have

Having just switched from a 1.7 to a 2.3 myself

2.3 wants to be warm and at wot

1.7 will do whatever you wanted just not with
Much power .


Like a formula 1 car , doesnt like to idle
At a stand still (IMG:style_emoticons/default/beer3.gif)

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arne
post Jun 24 2017, 08:47 PM
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What cams in each?
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Tastyplacement
post Jun 24 2017, 10:38 PM
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QUOTE(arne @ Jun 24 2017, 09:47 PM) *

What cams in each?


Actually, that's a good point because the 2.3 has a particular cam, 307 Dur. x .500" lift, not sure how wild that is.
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Tastyplacement
post Jun 24 2017, 10:40 PM
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QUOTE(Rand @ Jun 24 2017, 09:13 PM) *

I've never had luck with carbs and no choke being a friendly cold start combo. Surprised the 914 works so well. Does it run really rich after warm up?


Yep, actually I think the idle circuit in the 914 is really rich, while it leans out in the main circuit. My a/f gauge was reading 8.5 at low RPMs, which seemed really rich and then 12 or 13 at WOT
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thelogo
post Jun 24 2017, 10:57 PM
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I always thought cold start
Meant like cold climate
Alaska ,Minnesota Wisconsin

But even southern ca 96 deg
And texas .

Cant imagine what cold start in
Real cold would be like



And you said you had a 550 replica



. And how tall is the car

Im 6ft 2 in a 914 .

Having a felling 550 is a bit tighter
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IronHillRestorations
post Jun 25 2017, 11:38 AM
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Performance cams usually mean less than stellar cold start properties. Hold it at about 2000 rpms until it gets up to temp.

From the info you've shared, the 550 is a much more radical engine and cold starting will never be great on an engine like that.
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rhodyguy
post Jun 25 2017, 12:54 PM
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Feather the throttle a bit on the big engine when it lights up. It will settle down. Typical.
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r_towle
post Jun 25 2017, 01:31 PM
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I may be wrong, but I think one of our vendors sells a throttle handle that allows you to set the throttle at a higher speed from inside the car when you start it up....its something that the six has, but I recall someone making it for the four...not sure.

For cold start, that camshaft will require some extra revs to warm it up prior to letting it idle...just normal.
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Tastyplacement
post Jun 25 2017, 06:04 PM
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How about going up one jet size (+5) on the idle jets?

I looked tonite and the Spyder has 50 idle jets, not sure why I thought they were larger.

QUOTE(r_towle @ Jun 25 2017, 02:31 PM) *

I may be wrong, but I think one of our vendors sells a throttle handle that allows you to set the throttle at a higher speed from inside the car when you start it up....its something that the six has, but I recall someone making it for the four...not sure.

For cold start, that camshaft will require some extra revs to warm it up prior to letting it idle...just normal.
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ChrisFoley
post Jun 26 2017, 09:31 AM
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The 50s are too small for the 2.3L.
55 would be better, and probably is enough to set the idle mixture for easier cold starting.
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Tastyplacement
post Jun 26 2017, 11:23 AM
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Thanks chris, I am going to try the 55s, which I have on order.

By the way, I got your shift linkage put in my 914 recently and it truly is spectacular...

QUOTE(Racer Chris @ Jun 26 2017, 10:31 AM) *

The 50s are too small for the 2.3L.
55 would be better, and probably is enough to set the idle mixture for easier cold starting.
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porschetub
post Jun 29 2017, 11:34 PM
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Wow huge jets...why,those mains are massive, what vents are you running ,if that makes it go your vents are too big.
Bigger is not better,camshafts are the same (IMG:style_emoticons/default/sad.gif)
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Rav914
post Jun 30 2017, 08:29 AM
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QUOTE(porschetub @ Jun 29 2017, 10:34 PM) *

Wow huge jets...why,those mains are massive, what vents are you running ,if that makes it go your vents are too big.
Bigger is not better,camshafts are the same (IMG:style_emoticons/default/sad.gif)


I'll buy that. I had 32mm vents on my 1911. Cold start, idle, and starting from a standstill required lots of throttle in order not to stall. I switched to 28mm vents and problem solved.
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ChrisFoley
post Jun 30 2017, 08:38 AM
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QUOTE(porschetub @ Jun 30 2017, 01:34 AM) *

Wow huge jets...why,those mains are massive, what vents are you running ,if that makes it go your vents are too big.


Those aren't too large for a 2.3L with a long duration camshaft.
It might even call for bigger mains and bigger airs.
I wouldn't hesitate to put 36mm venturis in those 44s if the engine is configured for top end performance.
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EdwardBlume
post Jun 30 2017, 09:47 AM
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(IMG:style_emoticons/default/thisthreadisworthlesswithoutpics.gif)

Somebody had to do it. Lets see the 550 Rep. (IMG:style_emoticons/default/cheer.gif)
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