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| GarretCB750 |
 Posted: Wed Nov 01, 2006 8:11 pm |
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Rookie
Joined: 01 Nov 2006
Posts: 6
Location: Sydney, Nova Scotia
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| I just got hold of a ATP turbo kit for a CB550 that was in a warehouse at the local honda delearship. It seems everything is there but a wastegate? Is there suppose to be a wastegate? I don't have the pipe that is on the exhaust exit side of the turbo, but if it doesn't require a wastegate i can fab my own right? |
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| Satanic Mechanic |
| Posted: Wed Nov 01, 2006 9:54 pm |
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Moderator
Joined: 04 Sep 2005
Posts: 309
Location: Munich, Germany
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Welcome GarretCB750!
Yes, there should be a wastegate, otherwise you would build up too much pressure. If you can make your own exhaust pipe, you can also make your own waste gate - it's nothing more than a valve which is held shut by a spring. The valve opens once a certain pressure is reached. Let me see if I can find a drawing I can scan and post here, but rest assured, it's far from magic.
What you need to think of, too (and what ATP and the like forgot) is a way to retard your ignition timing once the boost kicks in. The easiest way would be to statically retard the igniton, or limit the mechanic advancer, but an electronic ignition that retards timing based on boost pressure would be really nice. |
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| GarretCB750 |
| Posted: Thu Nov 02, 2006 3:11 am |
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Rookie
Joined: 01 Nov 2006
Posts: 6
Location: Sydney, Nova Scotia
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| does the wastegate bolt on before the exhaust pipe? Is it on the exhaust exit side of the turbo? |
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| Satanic Mechanic |
| Posted: Thu Nov 02, 2006 5:32 am |
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Moderator
Joined: 04 Sep 2005
Posts: 309
Location: Munich, Germany
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| Yes, it's on the exhaust side before the turbo. |
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| Satanic Mechanic |
| Posted: Thu Nov 02, 2006 8:18 pm |
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Moderator
Joined: 04 Sep 2005
Posts: 309
Location: Munich, Germany
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Here's a scan that shows the ATP turbo kit:
The tube at the left of the intake manifold leads to the waste gate (at the exhaust pipe to the left) and opens it once the boost pressure reaches a defined level (roughly at 4 psi).
Here are two pics of a Rickman CR 750 with a turbo installed:
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| GarretCB750 |
| Posted: Sun Nov 05, 2006 9:27 pm |
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Rookie
Joined: 01 Nov 2006
Posts: 6
Location: Sydney, Nova Scotia
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| Those pictures are great.. thank you , but i do have the front header and exhaust peice that connects the turbo to the engine, no sign of a bung or anything that suggests a wastegate is suppose to be present. Where would the line coming off the wastegate connect to, and is it possible to have a system that does not require a wastegate? |
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| Satanic Mechanic |
| Posted: Thu Nov 09, 2006 7:18 pm |
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Moderator
Joined: 04 Sep 2005
Posts: 309
Location: Munich, Germany
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| There are turbos which have an internal waste gate, but Rayjay (which I think ATP were using for all their kits) turbos didn't have one AFAIK. The line from the waste gate goes to the intake manifold - it's the pressure in there which needs to be controlled. |
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| GarretCB750 |
| Posted: Fri Nov 10, 2006 4:36 pm |
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Rookie
Joined: 01 Nov 2006
Posts: 6
Location: Sydney, Nova Scotia
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| I just got back from the honda dealership who built the bike and the mechanic doesn't recall a wastegate, and he said it was one of the first turbo cb500 in the 70's, probably why it never worked right. lol where could i pickup a wastegate that could easily be intergrated into the system?... are they rated for different pressures? |
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| GarretCB750 |
| Posted: Sun Nov 12, 2006 3:51 am |
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Rookie
Joined: 01 Nov 2006
Posts: 6
Location: Sydney, Nova Scotia
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| I found a wastegate on ebay for about 60 bucks..its has a 5 psi spring, inlet, outlet, should be easy to fab up to the header pipe. I was even thinking of grabing a wastegate off a scrap turbo car system. As long as its around 4-6 psi. Does this sound like it should work? |
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| Satanic Mechanic |
| Posted: Sun Nov 12, 2006 7:10 am |
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Moderator
Joined: 04 Sep 2005
Posts: 309
Location: Munich, Germany
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| As long as it has the right pressure (I wouldn't recommend much more than 4 psi with an otherwise unmodified engine) any wastegate should be ok. If there is a chance to get to the spring, you can even adjust it by installing a different spring or changing the preload. |
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