homebrew_86 |
Wed Feb 19, 2014 6:33 pm |
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Ok a brief rundown:
Full flowed AS41 clearanced by RIMCO
DRD 4340 chromoly 82mm Crank (Chevy journal)
AA 94mm Stroker pistons with Total Seal Gapless second ring
DRD 5.4" H-Beam rods
DRD 12.5 lb 4340 chromoly flywheel (8 dowel)
Engle VZ-25 cam (duration - [email protected]" and .470" lift with 1.1 rockers)
Dynamic balance on all moving parts
Aiming for a modest 8.5:1 CR
Let me know if I forgot anything.
So I know the VZ is a bit on the vicious side as far as the fast ramp is concerned and I'm aware of what it will do to my valve train if not kept in check. That being said, I still have a lot to learn about intake velocity and things of that nature. Going to big on the heads and carbs will decrease velocity at low RPMs and rob your low end power right??
So I'm kinda thinking maybe something along the lines of a 42x37.5 CB Mini Wedge or something smaller like a DRD L5 40x35.5
(Flow numbers for CB)
http://www.cbperformance.com/ProductDetails.asp?ProductCode=1421
(Flow numbers for DRD)
http://www.drdracingheads.com/xcart/DRD-L5-CNC-ported-type1-heads-92mm-bore.html
Ok, on to the carbs. Keeping the same flow velocity thought process I was thinking about dual 44s with the stock vent size of 36mm. Or is that vent too small? Should I bump the vent up? Dual 48s just seems like a lot and from what I've heard, most engines with 48s don't need them, rather a properly tuned 44. I'm guessing the carb decision will be slightly influenced by the head decision.
The overall goal is great low end to mid range, but not COMPLETELY dead on the top end. I want this thing drivable. Sorry for the novel, but this is my first build so I have no experience to base these decisions on. And if I'm WAAAAAAY off in my way of understanding how all this works, don't rip me, I'm trying.
Thanks! |
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Danwvw |
Wed Feb 19, 2014 6:37 pm |
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I take it this is going in a bug? |
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homebrew_86 |
Wed Feb 19, 2014 6:42 pm |
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Ha! I knew I was going to forget something!
Yes, into a bug. :oops: |
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jfats808 |
Wed Feb 19, 2014 6:53 pm |
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Tims stage 1s, Panchitos, or L5s. Dell 45s will be good for this build. If you run a 1.4 cam like a FK43 or FK44, then Id look into mini wedges, stage 2s, L7s, wedgeport/superpros. CR would have to compliment the upgrade of course of about 9.5-10ish. Your below .500 lift so you wont benefit much on going big heads. 40x35s are right in the ballpark imo. |
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[email protected] |
Wed Feb 19, 2014 7:00 pm |
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ditch the VZ idea and go simple, W120 or W125. And bump the CR to 9.5:1. It will run a long time and make a lot of power. |
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Danwvw |
Wed Feb 19, 2014 8:29 pm |
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So what kind of driving are you going to do with the car, Street or Track? Daily or Weekend? How easy do you want it to be to control the engine with the throttle? |
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MURZI |
Wed Feb 19, 2014 10:08 pm |
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Shove a FK44, CB1.25's and mini wedge ports on that thing. [email protected]
with 1.25's you will be at about .520 lift.. |
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downsbs |
Wed Feb 19, 2014 10:25 pm |
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Fk10, Tims' stage 2 and dell 45s. Works great in my car! |
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homebrew_86 |
Wed Feb 19, 2014 10:56 pm |
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[email protected] wrote: ditch the VZ idea and go simple, W120 or W125. And bump the CR to 9.5:1. It will run a long time and make a lot of power.
ok comparing numbers. i happen to have a DRD R302 on my bench right now. almost identical numbers as a W125 on 1.25 rockers. So 9.5:1 is still a pretty safe CR to run for a every-other-daily driver?
downsbs wrote: Fk10, Tims' stage 2 and dell 45s. Works great in my car!
I'm thinking a 260 duration is about as much as i wanna go. I don't want that power band creeping up to high. FK10 is about 266
MURZI wrote: Shove a FK44, CB1.25's and mini wedge ports on that thing. [email protected]
with 1.25's you will be at about .520 lift
the FK44 is kinda similar to this DRD cam i have. duration at .050 is within a couple degrees. just looks like the ramp up is a little more gentle. lift is within .010 too. kinda thinking this DRD cam might be the way to go after all. |
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homebrew_86 |
Wed Feb 19, 2014 11:00 pm |
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Danwvw wrote: So what kind of driving are you going to do with the car, Street or Track? Daily or Weekend? How easy do you want it to be to control the engine with the throttle?
Somewhere between daily and weekend driver. "every-other-daily-driver". definitely not part of the "odometer defender army". its not very fun to drive when its parked lol |
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[email protected] |
Thu Feb 20, 2014 2:41 pm |
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I ran the W120 with 1.25's and Mofoco ported and polished 050's and dual weber 44 IDF's. Most people who rode in my 72 beetle didn't even believe it was a VW motor because it had so much get up and go. This combo gave me some of the best throttle response I've ever had in a beetle. |
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homebrew_86 |
Thu Feb 20, 2014 4:27 pm |
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[email protected] wrote: I ran the W120 with 1.25's and Mofoco ported and polished 050's and dual weber 44 IDF's. Most people who rode in my 72 beetle didn't even believe it was a VW motor because it had so much get up and go. This combo gave me some of the best throttle response I've ever had in a beetle.
This was a 2276? Stock vents in the 44s? |
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[email protected] |
Thu Feb 20, 2014 4:41 pm |
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The W120 is overlooked by a lot of guys trying to build the "perfect engine".
But you will rarely go wrong with that cam. Yes you may give up a little bit of power, but it will always work well if you have dual 2bbls.
This was the cam the late Mark Herbert recommended in his "Recipe engine". It just makes a ton of power from off idle to 7k. |
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homebrew_86 |
Thu Feb 20, 2014 5:28 pm |
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[email protected] wrote: The W120 is overlooked by a lot of guys trying to build the "perfect engine".
But you will rarely go wrong with that cam. Yes you may give up a little bit of power, but it will always work well if you have dual 2bbls.
This was the cam the late Mark Herbert recommended in his "Recipe engine". It just makes a ton of power from off idle to 7k.
So what about this DRD cam that I have, John? The DRD R302 with 1.4s is almost identical to the W125 with 1.25s (DRD has 1 degree longer running duration, and 2 degree shorter duration at .050. Also DRD has .007 more valve lift with aforementioned rocker setups).
What kind of power curve can I expect with the DRD cam (basically the W125), lets say CB mini wedge 42x37.5, and dual 44 IDFs (or equivalent Dell 40s). Also bumping the CR up to 9.5 or so like you had suggested earlier.
I do plan on having the heads/manifolds match ported and thoroughly run through at a local shop. Not planning on skimping out basically. I don't need 5,000,000 horsepower, just want something impressive and easy to drive around town if i feel like it. |
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[email protected] |
Thu Feb 20, 2014 5:30 pm |
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I don't know a thing about the DRD cams. The ones I recommended will work well. |
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MURZI |
Thu Feb 20, 2014 6:00 pm |
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[email protected]. Man shove that thing in there. 160hp. Rev to 7k and tire smoking low end. Just guessing... But I can tell you even with [email protected] it will drive fine. The displacement makes it work. Set it at 9.5:1 and done. |
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[email protected] |
Thu Feb 20, 2014 6:09 pm |
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If you want to run .500" lift at the valve you are far better off with a ratio rocker cam and "smaller" rockers than trying to stretch a 1.1 cam with 1.25s.
That's my logic in matching the heads with .500" lift with a 1.3 rocker. |
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homebrew_86 |
Thu Feb 20, 2014 6:16 pm |
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Yeah murzi, I think that's where I'm headed. Gonna roll with that DRD cam since its just sitting there on my bench taunting me. [email protected], CB Mini Wedge 42x37.5, and dual Weber 44s (or Dells - whatever i find)
All things considered, this first build has been and will continue to be an learning experience. If I decide I want to tweak the numbers on the next one, I'll know which way to go when the time comes. Regardless of what happens, this thing is gonna be a blast to drive.
Thanks for the comments and pointers guys. Keep it coming if you've got more to say. |
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homebrew_86 |
Thu Feb 20, 2014 6:21 pm |
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[email protected] wrote: If you want to run .500" lift at the valve you are far better off with a ratio rocker cam and "smaller" rockers than trying to stretch a 1.1 cam with 1.25s.
That's my logic in matching the heads with .500" lift with a 1.3 rocker.
So more lift from the cam and less from the higher ratio rockers. Am I understanding you correctly? Are the higher ratio rockers harder on your valves or something like that? |
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[email protected] |
Thu Feb 20, 2014 6:30 pm |
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No. What I'm recommending is to run a ratio rocker cam with 1.3 rockers. The lift moderation (only .050" less) will let things last much longer, and the power "reduction" will be insignificant, especially since you are not trying to get every last 1/2hp. |
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