Heat Riser Q's
Thread Starter
Melting Slicks
Joined: Dec 2003
Posts: 2,487
Likes: 1
From: Sydney
Heat Riser Q's
Hey all,
I am getting a little suspicious of the heat riser on my '70 SB, the exhaust note out of the side pipes always seems to be louder from the LHS pipe, and off idle acceleration can bog down sometimes quite strangely. I mean when cold the heat riser moves quite freely but when hot it doesn't seem to be completely open.
The winter here is non-existent. I mean winter here in Sydney is about as cold as an english summer (no offence to my UK bretheren), so do I really need a heat riser?
If the answer to that is no, is all I need one of those spacers that replaces the heat riser. If so where is the best place to get it from, and can I get it in stainless steel (I like stainless steel
)
Cosmic
I am getting a little suspicious of the heat riser on my '70 SB, the exhaust note out of the side pipes always seems to be louder from the LHS pipe, and off idle acceleration can bog down sometimes quite strangely. I mean when cold the heat riser moves quite freely but when hot it doesn't seem to be completely open.
The winter here is non-existent. I mean winter here in Sydney is about as cold as an english summer (no offence to my UK bretheren), so do I really need a heat riser?
If the answer to that is no, is all I need one of those spacers that replaces the heat riser. If so where is the best place to get it from, and can I get it in stainless steel (I like stainless steel
) Cosmic
Pro
Joined: Nov 2004
Posts: 607
Likes: 0
From: North Alabama
Yes, you can do without it. You can get a SS part to replace it from just about any corvette catalog. However, the other thing you can do is remove it, take the the valve (flapper thing) off the axle it rotates on and put the heat riser back on your car. That way you have the effect of losing the riser and maintaining the original look. 
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
My vote would be to get a new one. If you disable it, your choke may not fully open. I know you said you don't need a choke where you live, but on cooler mornings, it may prevent poor performance.
Drifting
Joined: Sep 1999
Posts: 1,970
Likes: 91
Might sound strange, but I got rid of the riser valve because of the cold.
By design,the valve stays somewhat closed during warmup, so the hot exhaust's restricted flow helps warm the choke. Unfortunitely this restricted flow at the other end,(mufflers), causes MUCH MORE condensation in the right muffler than in the left one. Since the muffler sit at an angle this condensation lays at the lower front edge of the muffler. Doesn't take long to rust out
I've replaced my right muffler twice before I smartened-up and put in a spacer. The extra minute or so it takes to heat the choke is hardly noticable, but I now have equal condensation at the two mufflers. Don't know about you, but I have never heard anyone complain their vette isn't hot enough.
By design,the valve stays somewhat closed during warmup, so the hot exhaust's restricted flow helps warm the choke. Unfortunitely this restricted flow at the other end,(mufflers), causes MUCH MORE condensation in the right muffler than in the left one. Since the muffler sit at an angle this condensation lays at the lower front edge of the muffler. Doesn't take long to rust out
I've replaced my right muffler twice before I smartened-up and put in a spacer. The extra minute or so it takes to heat the choke is hardly noticable, but I now have equal condensation at the two mufflers. Don't know about you, but I have never heard anyone complain their vette isn't hot enough.
Racer
Joined: Sep 2001
Posts: 397
Likes: 1
From: CORTLANDT MANOR NY
I got tired of the heat riser sticking closed so instead of replacing it I took some wire and tied it open. It can be removed in 5 minutes if need be or it can stay tied open for as long as I like. No appreciable difference here in cold NY. It just takes a couple of extra minutes to warm enough to release the choke. No big deal.
