When I searched this site I found some of this information, but thought Id fill in some of the blanks for folks like me that wanted more.
In all the dual images the SP1 is on the left.
Image 1 Note that the exit angles of the headers into the mid-pipes are quite different.
Image 2 The header mount faces are very different.
Image 3 I just took a smidgen off the OD of the SP2 header (approx 0.5mm) flange for an easy fit in the SP1 head.
Image 4 The measured dimensions of the parts I had.
The flat face on the lower of the SP2 flange is going to interrupt the smooth exhaust stream from an SP1 head. Whether or not this is going to present any problems remains to be seen its not ideal for sure.
FWIW the sp1 looks better as they made too much change to the sp2, look at the front header and that stoopid D shape, the sp2 throttle bodies and injection makes the 3 hp more up top not them headers IMO
"Exercise restraint and discipline, only responding to posts from legit customers and those with constructive positive intent, you will find that the handgrenades explode harmlessly. You have many satisfied customers who are happy to have the parts you've made. My suggestion to you is keep making good parts, keep getting more customers, take care of them and let them speak for you."
If you don't mind me asking what is the point of this?
There has to be at least a dozen SP1 vs. SP2 exhaust questions every week. The point of this is to help spread CORRECT information regarding some of the differences, Mmmkay
well do what i did and combine the 2 of them to get the best of both for a sp1. i used the sp1 front pipe down to under the oil pan. clamped it to the X pipe of the sp2. also welded the rear sp1 2 piece together and clamped it to the rest of the sp2 lower section. works good with sp2 swingarm. the sp2 X pipe is much better then the 2-1-2 sp1 pipe. can pull the fairing and get pics if anyone cares
There has to be at least a dozen SP1 vs. SP2 exhaust questions every week. The point of this is to help spread CORRECT information regarding some of the differences, Mmmkay
Good info, Thanks!
So the sp1 header pipes are better than the sp2's
Good for me since I have an sp1.
The dozen questions a week you speak of are not "sp1 vs. sp2" header questions. They're "why wont slipons for sp2 work on sp1's" and vice versa.
" The "D-Shape" flattens out the inside radius to increase flow on the exhaust cycle and provides a shelf to prevent reversion on the overlap phase of the camshaft timing. "
so I wasn't trying to turn this into a "technical" thread or jack it by any means. D shaped ports do have a purpose though, and have been a long standing thought among cylinder head porters of racing engines to be the optimum port shape. that quote was taken from edelbrock by the way. the flat floor gives the most air the straightest possible shot at the valve opening. or from it in this case. it not only helps to improve flow on the floor of the port, but also helps with reversion as stated above.
if you don't know what that is I'll try to explain it in simple terms as it a fairly complex process that happens basicaly two ways.
think of your exhaust flow as a bunch of tennis balls. your exhaust valve opens and the tennis balls start flowing. when they hit something such as a bend in the pipe or a step in the pipe they start to bounce back toward the exhaust valve. the flat spot of the D shape gives them something else to bounce back off of instead of trying to back feed into the cylinder again.
the second part of it is the valve overlap where the downward travel of the piston starts, as the exhust valve is still slightly open. this creates a split second of vaccum in the exhaust that starts to back fill the cylinder leaving less room for the fresh air/fuel mix to fill it. Having some kind wall or flange on the outer surface of the port impedes the backwards flow, but not the forward flow so much.
Are the exhaust ports themselves on the SP-2 D-shaped as well or are they the same as the ports on a SP-1?
Maybe someone else can answer that, but I'd guess that the ports will match the pipes i.e. SP2 casting is probably "D" shaped. Unfortunately both my motors are SP1's.
Maybe someone else can answer that, but I'd guess that the ports will match the pipes i.e. SP2 casting is probably "D" shaped. Unfortunately both my motors are SP1's.
the SP2 head has Dshaped ports to match the SP2 header while the SP1 is round like the header.
my problem is i have an SP1 with sato banzis and an SP2 header, its time to frankenstein a header.
14 track days this year= lots of dirt. 2 track days ago i got dive bombed in a corner and sent off the track, grass, dirt and mud. last time out i went to the drag strip and did excessively long burnouts with worn out track tires. threw rubber all over everything, definitely needs a thorough cleaning.
Are the exhaust ports themselves on the SP-2 D-shaped as well or are they the same as the ports on a SP-1?
I'm lookikng at using SP-2 headers on my SP-1 motor with a custom map of course.
As far as I know SP2 motor exhaust exits are D-shaped like the header. That is whey you can use SP1 full systems on SP2 motors, but not 2p2 full systems on an SP1 motors.
But, I think you can run SP2 OEM headers on an SP1 though. Some people here have done that as far as I know so they can run SP2 slip-ons on their SP1.
As far as I know SP2 motor exhaust exits are D-shaped like the header. That is whey you can use SP1 full systems on SP2 motors, but not SP2 full systems on an SP1 motors.
But, I think you can run SP2 OEM headers on an SP1 though. Some people here have done that as far as I know so they can run SP2 slip-ons on their SP1.
About the port shape... yes the ports in the SP2 head are indeed D-shaped to match the inlet of the headers.
But the 2nd para... you are contradicting what you say in the 1st para. This was the whole point of this thread... to say that SP1 headers work on SP1 & SP2, but SP2 headers are for SP2 only.
This is a great thread... the question came up recently and I found this old thread for answers.
Some differences between SP1 and SP2 headers
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