Hybrid stroker project
#571
Spencer, I' noted the exhaust earlier. Because they flow so well from the factory, it is not really necessary to do much work. However, I did pick up a bit of flow by working on a couple areas. I did not have the exhausts tested prior to the initial testing and porting so I don't have a baseline ( I am not as concerned with them). By most superflow measurements, it looks like I picked up around 5-10 cfm.
#574
Yes, Dave Sarno. SCH cylinder heads. He is a member of the Bonneville 200+ mph club for years.
He builds some of the highest hp reliable engines around here.
I talked to him about possibly doing port work for others and he would do it but has a pretty long wait time.
He was impressed with what I had done. I was pretty happy to hear that coming from him.
#575
The valves are cut with 3 angles
the 45 degree is from outside and about 1/16 wide seating very close to the edge
the next angle is a 30 degree that is about 1/16 wide
the next is a 25 degree angle about 1/16 wide
the seat angles are (starting from throat into combustion chamber)
70 degree angle from about 1/8" of seat edge with about 1/8" width
60 degree angle about 1/16" wide
45 degree angle less than 1/16 "
30 degree angle less than 1/16" out to chamber
the 45 degree is from outside and about 1/16 wide seating very close to the edge
the next angle is a 30 degree that is about 1/16 wide
the next is a 25 degree angle about 1/16 wide
the seat angles are (starting from throat into combustion chamber)
70 degree angle from about 1/8" of seat edge with about 1/8" width
60 degree angle about 1/16" wide
45 degree angle less than 1/16 "
30 degree angle less than 1/16" out to chamber
#576
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Joined: Aug 2009
Posts: 2,239
Likes: 2
From: Bangkok, Thailand, Milpitas, CA & Weeki Wachee, FL
Shawn:
I love your illustration, but I see 4, where are the other three located and what values? Purely asking out of curiosity. 7 angles sounds amazingly complicated, but obviously it worked wonders.
I love your illustration, but I see 4, where are the other three located and what values? Purely asking out of curiosity. 7 angles sounds amazingly complicated, but obviously it worked wonders.
#577
#581
Maiden voyage tonight.
Back in black, and she's a bad bitch!!
I've been running it quite a bit in the shop while dealing with a clutch issue. Darn master cylinder decided to take a crap while sitting.
I put my smallest spring in and even at 10 psi, it is crazy fast. Just shreds the tires once boost comes on. Wants to hit redline immediately. With the 76mm throttle body, I'm finding that modulating the throttle is difficult. I have to be careful once into second gear that I keep my foot out of it or it'll get sideways and just hit rev limiter.
Looking forward to doing some tuning in the next couple of days. If I feel like everything is OK tomorrow night, I may take it to the track weds to do some low boost shake down runs. Judging by my MAF readings, I should run around 120ish at 10 psi.
To recap.
Hybrid 86mm stroker crank using mitsu rods
FRF deck plated block using Wiseco 4.155 SBC pistons
Head done by me using 47mm valves. Flowed 250cfm at .500 lift
stock cam for now
Intake by Bruce 95one. Short runne,r large plenum. uses 928tb (76mm)
Headers,crossover and exhaust by FRF
Clutch by FRF
So far the only issues I have are that my oil cooler thermostat must be stuck as there is no heat getting into my oil cooler. However, There is oil flowing through it, so I will have to dig into it deeper.
Couple pics at the car wash. Crappy I know, just had to document the first drive.
Back in black, and she's a bad bitch!!
I've been running it quite a bit in the shop while dealing with a clutch issue. Darn master cylinder decided to take a crap while sitting.
I put my smallest spring in and even at 10 psi, it is crazy fast. Just shreds the tires once boost comes on. Wants to hit redline immediately. With the 76mm throttle body, I'm finding that modulating the throttle is difficult. I have to be careful once into second gear that I keep my foot out of it or it'll get sideways and just hit rev limiter.
Looking forward to doing some tuning in the next couple of days. If I feel like everything is OK tomorrow night, I may take it to the track weds to do some low boost shake down runs. Judging by my MAF readings, I should run around 120ish at 10 psi.
To recap.
Hybrid 86mm stroker crank using mitsu rods
FRF deck plated block using Wiseco 4.155 SBC pistons
Head done by me using 47mm valves. Flowed 250cfm at .500 lift
stock cam for now
Intake by Bruce 95one. Short runne,r large plenum. uses 928tb (76mm)
Headers,crossover and exhaust by FRF
Clutch by FRF
So far the only issues I have are that my oil cooler thermostat must be stuck as there is no heat getting into my oil cooler. However, There is oil flowing through it, so I will have to dig into it deeper.
Couple pics at the car wash. Crappy I know, just had to document the first drive.
#585
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Joined: Jul 2001
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From: Marietta, NY
One thing that is changing in the race world is the multi-angle valve job. A lot of good shops are now using CNC machining to do valve work, that means you can program in curves instead of step angle changes. You still need some sort of angle change to make up the vale seating point on the port - but all the rest can be curves.