| Author | Message | ||
     Buell_zen |
In looking through the archive I see very little about people posting performance with ported heads with stock valves(Stage 1). Since larger valves would lose low end torque, some might consider that as best for street bikes. Does anybody have dyno charts that they could post in the Knowledge Vault? I think we all would be interested in text comments too! Thanks. | ||
| Reepicheep |
The Buell configurations are arguably stage 1 or stage 2 over the sportster configurations in the first place. People drop thousands of dollars into stock sporties and are thrilled to get to where my Cyclone hit with $300 worth of intakes and exhausts and a low speed jet. Aaron and Pammy can both deliver a fantastic collection of parts and work to get you whatever balance you want to reach. Just search for posts by them through the archives, and you will find lots of gems of wisdom. | ||
| Buell_zen |
Aaron and Pammy can both deliver a fantastic collection of parts and work to get you whatever balance you want to reach. Just search for posts by them through the archives, and you will find lots of gems of wisdom. I have looked at all of aaron and pammy's posts. I have also looked at almost all of the related posts in the archive. That is why I asked the question. I still have many questions. For example, I have an XB9 and don't know if doing a little porting will hurt or help my low end torque and smoothness. Most of my riding is done just puttering around town. I suspect this might be a topic of general interest as I think I am not the only non-racer here. | ||
| Glitch |
Buell_zen, ya may wanna just give 'em a call. Aaron won't steer you wrong, and Pammy and Wes won't either. From what I've heard and believe, the heads on the XB flow really nice. Aaron once said that if you have the Buell race kit a head job may just make the torque hole bigger and more noticeable. I'm thinkin' more displacement for myself. | ||
| Jerseyguy |
Glitch, I'm thinkin' more displacement too. Maybe 1250 ccs + a bigger throttle body over the winter. | ||
| Glitch |
Jersey, I think we top out at 1200, but that's with the cases machined, not that that would scare you off. Without machining, it's 1050. I've been thinking 1200, 12 throttle body, and 12 headers, and a Drummer. Or 1050, BMW 1150 injectors, and a Drummer. Since this is the cheaper way out, and I'm cheap, this may be the answer for me, and make the wife less stressed when I answer the "How much is all this gonna cost?" question. | ||
| Alex |
Buell_zen, if You like feel free to direct Your questions to me. If the heads are ported right using stock valves and without enlarging the valve seat ID You will never loose torque down low for the simple reason that Your engine draws more air through the same seat ring square area. The laws of physics tell us that raising the flow without enlarging the square area (read: square area of the seat ring) results in higher flow velocity. This leads to better cylinder fill giving more torque. Many head porters stick to bigger valves. I donīt as long as I get enough flow. A stock 1.81" Buell TS valve can end flowing above 160 CFM at 10" test pressure and .550 lift; a stock 1.565" Twin Cam exhaust valve can flow above 130 CFM at 10" test pressure and .550 lift. Many head porters would use 1.9" or 1.94" intake valves with 1.61 to 1.62" exhaust valves to reach these values. Best regards Alex M-TeK Engineering | ||
| Buell_zen |
If the heads are ported right using stock valves and without enlarging the valve seat ID You will never loose torque down low for the simple reason that Your engine draws more air through the same seat ring square area. Then you don't notice a more pronounced dip in the middle of the power band as Glitch said was possible with porting? | ||
| Glitch |
Sounds logical to me. Note to self, learn plural terms. (Message edited by glitch on August 31, 2004) | ||
| Buell_zen |
Alex, here are a few questions: 1. 100+ rwhp is great for an XB12. What would you get with an XB9? 2. Would porting just increase HP and torque just at high RPM or would that also help low and midrange too? 3. Does the manifold and throttle body need to be done at the same time? Thanks, Bob | ||
| Alex |
Hi there, Bob asked: "Then you don't notice a more pronounced dip in the middle of the power band as Glitch said was possible with porting?" I say: "Not really. We normally end with a power and torque curve that keeps its basic shape but simply moves upward to a higher level. The reason is that torque dips are seldom related to head flow. Torque dips are most often the result of dynamic things or state of tune like intake tract length, exhaust length or air fuel ratio." Bob, hereīs the rest of my answers: 1. 100+ rwhp is great for an XB12. What would you get with an XB9? With a free flowing intake system like FAST and a less restrictive exhaust a Stage I head typically ends in the 90+ rwhp range for a XB9 engine without further modifications (but be aware that 90 horses may be 85 or 95 depending on dyno and method of measurement). 2. Would porting just increase HP and torque just at high RPM or would that also help low and midrange too? It will help low and mid range. Still You will feel the highest gains at high rpm for the simple reason that air demand is max at high rpm. 3. Does the manifold and throttle body need to be done at the same time? We modify the throttle body while still keeping the 45mm throttle plate. This is part of my Stage I treatment and should be done. Best regards Alex M-TeK Engineering |
