preparations for a turbo bandit questions.

[boilerdude]

So I just ordered a set of hayabusa pistons. having ideas on probably using the proboost street kit. I have the engine almost out of my spare bandit. Aside from a couple rounded out header bolts. I have 2 first gen bandits. one that I'm currently riding and one thats a spare. . I'm setting up and trying to make connections figuring out who's going to do the engine work around here and whatnot... And also gathering input.

I'm looking for anything right in the 200 hp range. If it makes 220 230 that would be great. But the main priority is having it stay together for a few thousand miles.

So of course I have lots of questions still even with the treasure vault of info we have here. Again this is my first time. Everybody's gotta start somewhere. Please spare me the old "I learned by just doing it and blowing mine up a bunch of times and thats how you should learn too..."  I'm trying to get all the info I can and get it right the first time.

 

Ok here goes question #1. Compression ratio. The hayabusa pistons Drop compression. Since I'm only looking for 200-230 hp I dont necessarily need 8:1 compression. I wonder if I would like the bike to have a little bit of it's own bandit grunt still intact before the turbo hits. What is a safe amount to mill the block to bump the compression up a smidge? Or should I just leave it low compression and let the turbo run the show?

 

Thanks for any input whilst I scour the threads for more input.

 

Edited September 3, 2015 by boilerdude

[boilerdude]

sorry dont mind the comment about spare me the routine. Just at most sites there always seems to be that one guy thats like "If you need to ask questions then you shouldn't do it..." you guys know what I mean.

[Blower1]

Comp. ratio x boost (bar) + Comp. ratio < 16 and you are on safe side

For example 10.5 x 0.5 + 10.5 = 15,75

I have in my supercharged EFE 11 x 0,5 + 11 = 16,5

No detonation and good torque

Edited September 4, 2015 by Blower1

[Captain Chaos]

Blower1 I think you mean: Comp. ratio x boost (bar) + Comp.ratio < 16

Or you could also say: Comp. ratio x (boost + 1) < 16

[boilerdude]

Shit my bad. That was absolutely helpful.

 

What I meant was how much can you safely mill off the bandit block.

Lets say I was looking for stock bandit conpression. 9.5 I think or something or rather. So how much do I mill off the block.

My question wasnt so much about how much boost I can run with how much compression... well it was... but my mistake the real question is how much do I mill the block to reach... yea that.

Edited September 3, 2015 by boilerdude

[Gixer1460]

More words in explaination...... Comp ratio ie 8 (ie 8:1) multiplied by boost max used in Bar ie 1 bar = 14.7psi plus the CR ie 8 again, all must be equal to or less than 16...... so you get ........ 8 x 1 = 8 + 8 = 16. so that would be ball park. Lets go more extreme........ 7 x 2 + 7 = 21 so could be too much.

Personally I think that formula is a bit conservative as using my own build numbers I get ........9.5 x 2.5 + 9.5 = 33.25 which is definitely the wrong side of 16! Now maybe I got lucky but don't think so. One question is - are you using carbs and normal ignition or EFI and engine management?

I believe that the former set-ups cannot control fuelling / ign. timing accurately enough to get the optimal performance out - the latter allows better control without random fluctuations that cause detonation and engine failure.

Very few get it bang on right first time - its just how badly its wrong that makes or breaks a build.

 

[boilerdude]

the proboost kit is blow through carb kit. Thanks all of you btw.

I edited the above post to be less prickish. But also ask the question in a different way.

how much can I mill off the bandit block before I need to refuckulate the cams and such.

To reach a compression ratio of approximately stock bandit again...

Like bore x stroke + current compression ratio. How much do I need to cut.

First off how much definitively do hayabusa pistons drop the compression? And then with the 81mm bore and whatever the stroke is. How much should I mill to get back to my target of approximately stock bandit compression.

 

Edited September 3, 2015 by boilerdude

[boilerdude]

Ok so I suppose thats half a stupid question because I'm sure the machine shop knows the bore stroke compression "so we need to mill this much" equation. So the real question I suppose is... What's this I'm hearing about having to reset the cams once you mill the block so much. Am I milling that much?

Edited September 3, 2015 by boilerdude

[Duckndive]

if you ignore the ref to a dot head the info here is relevant

http://oldskoolsuzuki.info/forums/index.php?/topic/885-gsxr1300-pistions-and-750-dot-head/&page=1

 

Edited September 3, 2015 by Duckndive

[boilerdude]

So you're saying busa pistons dont lower the compression at all? And the famous mustapha dump was either full of shit or all those people forgot they're specs.

[boilerdude]

So do hayabusa pistons lower the compression in a bandit with bandit rods as I and some other confused folks have been hearing or no? And if yes how much?

 

Shit that should have been the first question. short and sweet...

[Duckndive]

So you're saying busa pistons dont lower the compression at all? And the famous mustapha dump was either full of shit or all those people forgot they're specs.

Simply pointing out that you should not listen to hearsay "or I was told"............

Yes they Do lower the C/R ...but you will need to Do the sums for the parts that you are using in your application.....to find your C/R ...

But there is no mileage in removing material from the block that's for sure....

 

 

[boilerdude]

Right. It's the head that gets shaved then? thats another dumb question. I'm sure I'll have a bunch more slightly wrong questions. Again just bare with me and thanks for the help so far.

So I leave the block alone aside from boring it and installing whatever studs and such... And It's the head that gets shaveded I reckon? So I must sound like an idiot when I'm talking about shortening the block.

 

Edited September 3, 2015 by boilerdude

[Gpz1100_Convert]

given the increase in torque and the target of 'around' 200bhp..... a better question would be why skim the head at all?

You'd need to deck the head surely and check the clearance on the valve/head first. A strike on a valve would be far more serious than a loss of punch before the boost comes in.

Also. You should note that you'll rarely need that punch. I am fairly sure I lost some on my bandit (or I may have just gotten used to it now) just before the turbo starts making boost but I doubt you'll miss it. The fact is you should be able to tune that out provided you do not install a huge turbo or get the carburation wrong. You will btw.... it is part of the process. Once you have a turbo on the road you'll end up chasing the boost all the time anyway

Mark

 

[boilerdude]

Right on. So I shouldn't worry so much about getting the compression back up. Anywhere in the 8 point something to 1 range will at least be on the safe side for detonation prevention. 

And like you said how much should I really concern myself with grunt before the turbo anyway.  If the turbo is not huge and spools reasonably quick.

So just a bore and hone. Maybe some light porting. And If I decide to shave the head a very very minimal amount should be all that I take off.

[boilerdude]

Btw that is a concervative number. Another question is how much power should I expect bandit bottom end be able to handle.

I dont have some personal limit that I want to stop at 200. I just want to make sure the motor holds together for a while... So again If I can manage a safe 220-230 that will be fantastic.

From "what ive read" or at least what I think I remember from what I read somehwere... Is that the bandit bottom end does not like much more than 250 hp. So I dont necessarily want to be all the way up there at 250. but backed off a tad from there. you know...

 

Edited September 4, 2015 by boilerdude

[Blower1]

Blower1 I think you mean: Comp. ratio x boost (bar) + Comp.ratio < 16

Or you could also say: Comp. ratio x (boost + 1) < 16

Fixed, thanks!

[vizman]

I wouldn't bother with skimming on a standard b12 motor if you are going to go turbo.

[Gixer1460]

There's nothing wrong with a GSXR / Blandit bottom end - it how they get treated that kills 'em. If you over-rev them ie. consistantly over 11,000 you'll snap them, excess revs + other areas that lead to oil failure will also kill the big ends and will usually take the crank pins out as well.

250hp was generally taken as the rod limit when using nitrous - turbo's are softer on rods but 300 is probably the upper limit as you don't rev a turbo motor......there's just no need!

[Fula28]

Worth noting stock b12 motors in GOOD health with no N/a tuning will make 160-210 Bhp depending on Turbo system etc. You just don't need to mess around with them no skimming or porting needed really , of course you still can do what you want but if just want a turbo b12 crack on. I cobbled my first turbo motor out old parts reused Gaskets etc and with WSR turbo system and second hand turbo made 209bhp 111lbs torque, Just to prove it would work and it did well , so my small amount of advice is make sure your motor is good and strong no burning oil or valve seat leaking,And go from there ! And worth noting you WILL DEFO need a lock up clutch.Unless you like wasting money on clutch packs ??? Lockups are a necessary upgrade am afraid and once fitted setup forget it. 

 

 

Edited September 4, 2015 by Fula28

[Paulm]

My B12 turbo motor is running Gen1 busa Pistons,a lockup clutch,and is otherwise stock and is circa 200bhp at 11psi according to the motors builder FBM (Dave Dunlop),you won't really notice the slight loss of power off boost,my bike motors along fine off boost alongside my cousins stock B12,once the boost gauge starts flickering though it's a different matter! Mine is running a IHI VF 10 turbo,good for 240/250 BHP,stock Pistons it was 160/170 BHP at 7psi,Pistons didn't like 15psi much though! Keep asking questions and you will get there,I'm still learning about turbos,but I sure know they are great fun in a road bike.

Edited September 4, 2015 by Paulm

[boilerdude]

you guys are fucking awesome.

 

The motor getting built already has a barnett clutch. It's not a lockup clutch but it's something. I'll see how that one holds up while it's in there.

[Captain Chaos]

you guys are fucking awesome.

 

yeah I get told that a lot.

Especially the fucking part.

[Gixer1460]

The motor getting built already has a barnett clutch. It's not a lockup clutch but it's something.

No its not and it will suffer for it. By the time you add enough spring weight to stop the slip you'd be hard pressed to pull in the lever! Nothing makes mid range torque like a turbo and that's exactly where the plates give up!

[boilerdude]

I hear ya. But it's just a clutch. I'll keep the oil changed and if the clutch thats in there gets fried. I'll be sure to get a better one.

 

http://www.proboost.fi/?p=33

 

anyway here's the kit. scroll down. the Bandit street kit. I dont really have any local connections in this. Who's gonna make the plenum and manifold and pressure fittings and figure out whats the right fuel pump and where to start with tuning. So the way this is looking so far is buying a kit. This kit...

any objections? better ideas?

I do wish it came with an intercooler...

Edited September 4, 2015 by boilerdude