to fast over SSR

General engine tech -- Drag Racing to Circle Track

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Biteme
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Re: to fast over SSR

Post by Biteme » Sat Jul 21, 2018 2:09 am

Post a pic of ssr profile as it is now.
I’m thinking you have turbulence.

I’ll have a look and find the tracing I made of factory ssr profile.

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Re: to fast over SSR

Post by steve cowan » Sat Jul 21, 2018 3:57 pm

Biteme wrote:
Sat Jul 21, 2018 2:09 am
Post a pic of ssr profile as it is now.
I’m thinking you have turbulence.

I’ll have a look and find the tracing I made of factory ssr profile.
i think after laying down short turn and making it slightly wider it has taken a 100ft/sec off the apex and brought it back down where it should be ok.
last week it was approx 450-480 ft/sec at the apex at all depressions,the pitot jumped up and down in the port,if i placed a 5/16 flowball at the SSR apex it would bounce and you hear the port it was noisy and the air sounded like was trying to reattach itself.
NOW this week end after modifying the SSR air speed is down to 380 ft/sec avg at the apex,with my very limited experience and from what i am seeing i am calling it good,i was hoping some head porters could say run it or tell me otherwise.
i want to move on to the exhaust side.
just to refresh
application 327 sbc 6500 rpm max,engine is in my car at the moment and at 3650pounds runs 12.80 @ 108 mph with stock 200cc sportsman 2
i believe the heads are to big and slow for the application and i can improve with a smaller faster cylinder head,this is just a fill in thing while i get the 383sbc finished.
165cc dart cast out to 178cc
avg port length - 5.51''
intake valve 1.94'' throat @ 89.5% - 1.73''
pinch - 1.81''
avg port CSA - 2.13''
236 cfm / 1.81'' pinch = 130.3 cfm/sqin
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Re: to fast over SSR

Post by Biteme » Sat Jul 21, 2018 5:34 pm

1.8 prp will give peak power at 6000rpm.
You can probably widen the prp a tad without losing performance.
Take 1mm off the wall beside the pushrod and retest.
It won’t really harm your airspeeds but I’m picking that’s where the restriction is.
If you do just the port you are testing if it’s a step backwards it won’t hurt performance.
Not sure why the numbers are reducing at high lifts. They should be flat lining after .5

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Re: to fast over SSR

Post by steve cowan » Sat Jul 21, 2018 6:16 pm

Biteme wrote:
Sat Jul 21, 2018 5:34 pm
1.8 prp will give peak power at 6000rpm.
You can probably widen the prp a tad without losing performance.
Take 1mm off the wall beside the pushrod and retest.
It won’t really harm your airspeeds but I’m picking that’s where the restriction is.
If you do just the port you are testing if it’s a step backwards it won’t hurt performance.
Not sure why the numbers are reducing at high lifts. They should be flat lining after .5
thanks for the info
i am going to check with tapped off intake and carb today and see how much it drops off,might check velocity in the individual runners as well just to see where it is at,dont know if this a help or a hindrance but just to see some data.i was told when i started these heads that 235 @ 500'' lift was a fair #.
i will test with intake and carb first then make the PRP 1,85'' and retest
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Re: to fast over SSR

Post by Biteme » Sat Jul 21, 2018 7:25 pm

Factory Dart Pro1 ssr
ACC849BE-74B5-4763-84E1-AE4368828A5E.jpeg
For a comparison, here’s a profile of RHS 220cc ssr
ACC849BE-74B5-4763-84E1-AE4368828A5E.jpeg
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Re: to fast over SSR

Post by steve cowan » Sun Jul 22, 2018 12:11 am

cast iron dart 178cc 001.JPG
cast iron dart 178cc 002.JPG
cast iron dart 178cc 003.JPG
cast iron dart 178cc 004.JPG
cast iron dart 178cc 005.JPG
cast iron dart 178cc 006.JPG
cast iron dart 178cc 007.JPG
cast iron dart 178cc 008.JPG
i had another look at the PRP this morning and noticed as cast it tapers from floor to roof so the pinch at the roof was smaller,so i evened it up and made the radius on the roof slightly bigger.Flow went up a few to 242 cfm @ 500'' lift dropped off slightly at 600''-241.5cfm 700'' - 239.2cfm and velocity around the pinch is 360 ft/sec and centre of SSR is the same,i think i am in a good place at the moment
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Re: to fast over SSR

Post by steve cowan » Sun Jul 22, 2018 12:13 am

cast iron dart 178cc 009.JPG
cast iron dart 178cc 010.JPG
cast iron dart 178cc 011.JPG
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Re: to fast over SSR

Post by steve cowan » Sun Jul 22, 2018 12:19 am

cast iron dart 178cc 012.JPG
flow tested twice to verify cfm change after PRP change,
this is the data and percentages of intake fitted.
team G low plenum using a 1205 gskt
heads are a 1204 size so i dont know if the oversize intake is a help,flow lose is similar to what i have seen from other peoples stuff on this forum
feedback appriciated
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Re: to fast over SSR

Post by Biteme » Sun Jul 22, 2018 3:02 am

Definitely on the right track!
From pics it looks like the finish on port is a bit bumpy.
If that’s the case it may benefit from some time with a 60 grit cartridge roll.
Other than that I’d call the intake port done.

The intake manifold is going to hold it back.
I use a team g also. Off memory I think it’s factory csa is about 1.7”.
The team g has plenty of meat for porting.
I took a couple of cuts from the long side of the runners and made them about the same size as prp. Cfm rose slightly by a couple of cfm with it bolted on.
The manifold runners can be slightly larger in csa than the prp without hurting performance.

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Re: to fast over SSR

Post by steve cowan » Sun Jul 22, 2018 5:22 am

Lol,
The Port is bumpy, this is my first effort to start porting cylinder heads and of course I pick a small port cast iron head to learn on,
But in all honesty I am happy with my first time, alot of people might look at the finish and call it rubbish and that's ok, I am confident to say everyone's first time was probably rubbish as well, anyway
Over time my finished product will hopefully improve.
I posted exhaust data a few pages back, I am flowing with a 10 inch pipe but around 400"lift the exhaust is spitting so I think from my research I need to blend throat into seat area better or work on the chamber but not sure how to proceed, the throat area is 83% of the exhaust valve diameter at the moment @ 1.245"
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Re: to fast over SSR

Post by Steve Haaf » Sun Jul 22, 2018 3:12 pm

Steve, your finish is not rubbish, it`s just roughed in. You can learn to make it pretty in time.

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Re: to fast over SSR

Post by steve cowan » Sun Jul 22, 2018 3:47 pm

Steve Haaf wrote:
Sun Jul 22, 2018 3:12 pm
Steve, your finish is not rubbish, it`s just roughed in. You can learn to make it pretty in time.
Thanks Steve,
I should of said roughed in, sounds more professional lol
Hopefully someone can give me some breadcrumbs on exhaust, some experienceed guys on speedtalk have given good advice and support, the general consensus is grind on junk heads and work it out, unfortunately I am impatient
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Re: to fast over SSR

Post by xanadu » Sun Jul 22, 2018 5:49 pm

Really liking this thread Steve. Very informative. Thanks for sharing your efforts

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Re: to fast over SSR

Post by af2 » Sun Jul 22, 2018 7:49 pm

Does the flow bench pull clock wise or counter clock wise? I had a toilet thought after hearing they flush opposite of ours.. :lol:
JK nice work!
GURU is only a name.
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Re: to fast over SSR

Post by steve cowan » Sun Jul 22, 2018 11:23 pm

af2 wrote:
Sun Jul 22, 2018 7:49 pm
Does the flow bench pull clock wise or counter clock wise? I had a toilet thought after hearing they flush opposite of ours.. :lol:
JK nice work!
Ha good one Adam,
I will check swirl meter and let you know :D
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