The addition of MSA air hornes

[5thhorsemann]

I just ordered a set, the reason I'm going for them now is that I want to see if they aid in cold starts by increasing the vacuum at the jets, all be it ever so slightly. Anything I should look for after this addition?

[Captain Obvious]

Haha! Yes, you should look for other ways to improve cold starts.

I thought horns didn't do anything for you until you get up into the higher RPM's where the air velocity into the carbs is a lot higher than at idle or when cranking to start? Could there be an effect at cranking or idle air velocities?

[tlorber]

I put air horns on a Supra I once had. They were quite loud!

As stated above, "velocity stacks" are designed to align air flow when it is moving at a higher volume and speed. Is your choke working properly?

[5thhorsemann]

Well, MSA is sold out for at least 2 months, any other sources for new or used out there?

[5thhorsemann]

I understand what the velocity stacks are designed to do, but extending the throat of the carb should still increase the vacuum in the carb body at startup.

[LeonV]

I understand what the velocity stacks are designed to do, but extending the throat of the carb should still increase the vacuum in the carb body at startup.

Can you please elaborate on the physics of this phenomenon? How are you going to increase vacuum at startup by extending intake length? This is a rhetorical question.

Air horns will aid in decreasing entrance losses, but more importantly, they tune the powerband by varying intake length. This has no effect at startup. Your cold start issues most definitely lie elsewhere.

[5thhorsemann]

Don't misunderstand me, I don't think it will make a difference, but if I only crank for 5 seconds in stead of 6 I would be happy. I am looking forward to see what the difference is at speed, the car runs awesom without them.

So does anyone have a source for good quality new or used stacks?

[LeonV]

It won't change how long you crank at all, not by even one-tenth of a second.

[Bonzi Lon]

Black Dragon seems to have them, called 'Ram Pipes', #55-160, $29.95 each.

Bonzi Lon

[5thhorsemann]

Didnt think of them, order placed, thanks Bonzi.

[5thhorsemann]

I should that BD is $40 a set cheaper than MSA and they look to be the same part.

[5thhorsemann]

Got the Ram Pipes, bolted them up and gave it a whirl. The car has been sitting for 10 hours + since I got to the shop this morning, and although it was a warm day for this time of the year it is still cool 50 degrees now.

Turned the key and the car fired as it always does but didn't start, on the second turn of the key it cranked for one to two seconds and started (was taking 5 or 6 seconds). The idle on a cold start is rough for a minimum of 30 seconds before the pipes went on, now it is like 15 seconds.

Now I know this is the first time starting with the pipes, and is likely to be a fluke due to the warm weather we had today, and I don't make rush judgements based on this tiny bit of information. BUT, the temp is going to be around freezing tonight, and if tomorrow mornings startup is like this evenings was, I'm going to call this idea a home run.

I'll report back in the AM on the starting issue and let you all know what difference I feel on the drivability front.