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Great info, I used Garrett's equations to calculate my numbers on pump gas, probably not super accurate. Might skip the porting and just get the valve job done, I already know the guides, seals and valve seats are a bit worn from oil burning and "eh" leakdown test results. I agree, I want 400 for going to 1/4 ,1/8, and 1.5 mile events where I plan to swap out the rear for a longer swingarm and grippier tire, and run e85. Pump gas tune will probably be 310-340. I'll have to figure out compression ratio for a setup with low 300's on pump and ~400 on E, i did shave the deck of the cyls down a mm on 20 psi with just busa pistons and the bump in low/mid end power is something I don't want to miss too much of by going with a real low CR. I hit 260hp+ boost creeping on 26 psi, but 10:1 AFR and 20 deg of timing pulled out which i believe is a pretty conservative tune. MTC says 10:1 with their turbo pistons and I think im around 9.8-10:1 now, so it shouldn't be too bad. I was under the impression BB turbos would cook themselves pretty fast without coolant, but if not that's definitely the better option

True, real number on the daily tune will probably be around 350. I do have watermeth and low ambient temps where I am, but knock could become an issue. On race days, I will have it on e85 which is a pain the ass to get here, but possible for events. That should be enough to run 400 without cooking anything (I hope). Looking at the compressor map for the gt30/71 if I can get enough efficiency with a ported head, that should be a pretty damn perfect turbo what I'm looking for. Wow, im making 250 at around 21 psi so that's good to see the effect a ported head can have. At that rate I should be able to run low 30s and still make power, thanks for that info

Hi, im building a better motor for my boosted b12, and am currently sizing turbos for my power goals (~400). I'm going mtc turbo pistons and maxpeeding rods with all the APE head/crankcase hardware with an efi conversion. According to my calculations I'll need about 38 psi of boost to achieve this with a pressure ratio of ~3.5, and mass flow rate of about 33 pounds of air/min. These are very fucky numbers and after a few hours of searching I couldn't find a turbo where the compressor map doesn't plot my setup at, or beyond the surge line. I can't run e85 too often or methanol because it's not available here (trying to keep it a streetbike) so I can't do much with fueling to adjust those numbers. But I've been told a ported head will make the same power with less boost, I'm going to send mine off to APE for an oversized valve job and port, but I still want to know how much it'll help so i can order the right turbo as soon as I can and swap the flange on the manifold. So guys with ported heads, what boost and horsepower are you at?? Thanks!

I'm running 4 clutch springs in my bandit, up from the regular 2 and it's been working great. All i did was shave down the nut the same amount of thickness as the 2 springs. However I've noticed that the clutch slave has deformed the metal guard over it enough to break it loose, rubbing it against the chain. When checked against my parts bike the first pushrod under the sprocket cover slides into the motor 8mm more than the stock motor, causing the slave to extend further than the guard allows, pushing it into the chain. 2 extra springs shouldn't add that much distance from what I remember seeing when I was working in the clutch area. I did replace the middle pushrod with one from a 2001 but they share the same part number to my 99 so it's not that. I'm just going to get some 5mm diameter rod and cut my own to lengthen it, but was curious if anyone else ran into this. I'm too poor for a lockup.

(99 b12) I'm reworking a lot of the sloppier parts of my bike from when I first built it 3 years ago, one of which is the fuel system. I have a standard size 255 lph fuel pump that was kind of "hanging" by the braided line between the battery and plenum, and have decided to build a sheet metal mounting plate for both. However I'm running into the problem where with the fittings installed the pump and filter are simply too long to fit horizontally in the area! I looked online for shorter pumps, however it seems Google has gotten far worse at filtering listings. I'd like to see what setups other folks here are running for mounting their pumps? I also remember seeing some in-tank methods used, but can't find the thread that it was in. Not sure if that's worth the headache of cutting open the tank or not thought!

Install error (i think?)- not sure how but last szn after taking off the head, i noticed 3 of the middle nuts were stripped off the studs. They were torqued to 50 ft lbs (and triple checked) when I put it together. They 100% were not stripped when I put it together (I even have an old video of checking torque right before throwing the valve cover on) I think I had the wrong length studs installed? I got a new set and made sure that they were in the correct orientation. rechecked torque at 55 ft lbs after letting it sit for a night. There were some scratches on the top of the jugs under the HG where the nuts were stripped, I assumed those were from the hg. I think I might have used those copper washers which I heard can lose tension overtime, who makes a good alternative? Main reason for the meth is i was about 200 deg intake temps on boost which was a little hot for my liking. With meth I sit around 160

Wow, glad to know. Whats limiting me is probably the afr which is fairly rich, but my power tapers off far sooner than the other charts of stock cams show. Next season I'll spice up the tune a little and maybe turn down the meth and see what that nets me. I had some issues with the APE head nuts coming loosing causing the head gasket to shimmy around a little, I'll probably pop the head off and inspect too. I have busa pistons but also shaved the cylinder a mm for extra compression so it's still fairly high.

Last dyno at 19 psi I made 238 hp and 165 ft-lbs. This is with .75 deg of timing pulled per psi and about 10.5-11 afr (playing it safe with watermeth). I peaked power at around 7k rpms and tq around 6k rpms, hp fell off by about 15 to the 10k rpm rev limit. Just curious what the shape of the graph would be with a set of 1100 cams as I have very long gearing and shortly past shifting into 3rd I'm out of peak power range when doing pulls. I'm happy with the peak power as it stock swingarm and I'd like to get some beefier rods in there before shooting for 300 (although I did boost creep to 270hp before the clutch started slipping on the dyno last season) Side note, I got the rolling anti-lag to work. Nearly flipped myself right over letting go of the button in 2nd at 6500 rpms haha. builds 6-8 PSI depending on how long I sit on it, huge help with rolls. Only took about 20 minutes to wire up to the horn button.

I've got 2 carb tops feeding into a larger vac line off a T, bov is completely open at idle. Under 12 psi opens beautifully, but above 12 I think there's some residual boost holding it shut briefly. I'll try cutting the spring and see if that helps. Pulls pretty strong vac using 2 sources, big improvement over just 1.

Anyone else ever run into this? Running a tial 50mm BOV on the lightest spring. I have 2 carb tops teed into a larger line that runs to the blow off. At low boost (Sub 10) it opens nicely, and I can hear the soft "woosh" but anything above that and I get compressor surge before the BOV opens. Sounds pretty sick, a loud chirp followed by the more traditional "woosh" but the whole reason I went for the 50mm was to eliminate surge. My HKS SSQV had no problems but it shat the bed. I'm pretty sure my watermeth ate the internal diaphragm which is why I selected for the piston and O-ring style tial. Any ideas? The BOV is fully open at idle (also not ideal, but this is still carb'd so it makes no real difference) so I don't think vacuum strength is my issue.

Excellent info. I've been meaning to look into lockups as my current method is 4 HD clutch springs and that gets a bit annoying in traffic. I'm already talking with a shop about an extended swingarm, and looking at rear shock options. Then it's efi in order to run e85 and some Carillo rods. Got schooled by a stretched nitrous zx10r and want to do something about it

My current launch is floating the revs to about 4500, then holding abt 3/4 throttle while modulating the clutch. Very hard to get right, I either ride the clutch too much or instantly wheelie. The limiter would be nice so bounce it off 4k while holding 1/2 or so throttle, get the turbo spinning juuust a little then dump it and go. But yeah, nowhere near WOT until 3rd

Wow, that thing is fast!

Nice! And yeah, my 60fts are 2+ which is def hurting times across the board. Gonna tune the ignitech adjustable limiter for a better launch. I was looking into boost by gear kits but it would be easier to mess with that during an efi conversion.

For anyone curious - bike (99 b12) and me with gear weigh in at 685lbs (cat scale) and dynod 260/149. These runs it made less, estimating 215-230 hp with the muffler on and 17 psi. Afr ~10.5 (little too fat for my liking, but it's a failsafe incase the meth stops working) and .75 deg of timing pulled per psi. Stock swingarm. Anyways - 60 to 130 mph: Best so far: 5.67 Worst: 5.99 (5 runs) Problem is wheelies in 2nd and 3rd, aswell as 3rd topping out at exactly 126 mph gps forcing me to hit another shift to clear 130 1/8: 7.34 @104 best, 7.6 @ 101 worst. Surprisingly consistent, both dragy and actual track times have me within a few tenths of that. 0-60: Best: 3.70 Worst: 4.01 Hard to get the launch right, purely operator error! N/a I ran 2.9, 3.1, and 3.0 consecutively. More controllable without boost in 1st lol. 1/4 - haven't really done much, rolled to a 13.20 @ 54 mph after letting off at the 1/8th. ET calculators don't work well on boosted bikes on stock swingarms, but we think it'll be right around the 10 mark based off roll races I've done against similar cars. Anyone have some times to share? Gonna focus on improving these areas over the summer. Have a dyno day tomorrow to try and throw some timing back in to liven her up a little.