Too much boost?

[Richd]

Hi guys,
And way too late in the program to be asking this but finally the supercharged sv1000 is on the dyno. The dyno guy was very sus on running over 7psi boost with a static comp of 9.5:1. The previous owner was running nearly double that and I'm waiting to hear back from him as to what fuel type and other details he was using.
Question being what do you lads think 9.5:1 non inter cooled with 100 oct could handle? The bottom end is stock and we're running 4 deg retard. It's a vague question I know but many people push 7 odd psi through a motor with standard compression, that being 11:1 and higher.
We're going to start with 7 lbs but I reckon it could go mre in its current set up.
Any thoughts would be awesome
Cheers. rich

[Deano]

Do you have a way of sensing det ?

I would expect 10psi would be ok

[Richd]

I didn't ask if he was using knock sensors but I assume so. As with a lot of these builds there is a fair deal of conflicting opinion but in my researches 10psi doesn't seem too greedy. Boost isn't the only story, flow rate is the other side of the equation.
What boost have you turbo boys successfully run at a roughly 9.5:1 comp?

[Yella]

Im running 10psi now with approximately 9:1 and no timing retard

[Richd]

So what's that on? Using pump fuel? What hp gain over stock?

[latheboy]

1989 gsxr750, 9 psi, intercooled, stock comp on a 75000 ish OLD motor ... 5°retarded.. 98 oct fuel .. all is good.

Don't assume he is listening for det... Make sure you ask..

[Yella]

96 ZX7, 98 pump fuel, if I think of it I stick in some octane booster aswell (sometimes) but have run it on 95 on the NFR/AFR runs when 98 is hard to come by. Dunno HP last time on the dyno it had 170hp up from 110hp stock but was running less boost

[Richd]

This is what I thought. Might as well start off a little lower then wind it up later. Thanks lads

[latheboy]

Is it carb or injected?

If carbed make sure you always have more fuel pressure than boost.

I started with 5PSI and turned it up from there.

[Deano]

Bandit 12 motor intercooled. 12psi last time on dyno but usually just run 10psi. 35deg or so of timing. Started at 100hp ended up with 200hp

[Richd]

Nice one, 200hp would be hard to get sick of. The SV is injected. Standard at 440cc I've whacked in 750's and am running a 1:1 rrfpr set at 43 psi base.
I just got off the phone to the dyno man........she's ready. Ran 168hp at 7psi, wonder what it'd do at 10. Going to pick it up tomorrow. Been a hell of a long time coming.

[MONO]

Did you say Supercharged, more linear boost easier to tune.

Q. how are you regulating boost, do you have a boost/rpm graph-max boost @ x rpm etc

[Richd]

Supercharged yes. A Rotrex c15-60. The boost is now controlled by another bov like what's on there now, just set to 7psi with a soft spring. This is a very recent mod as there was no boost control on there beforehand, it had potential to hit over 12 which raised some detonation eyebrows.
I haven't seen let alone ridden the old girl yet so haven't clapped eyes on any charts thus far but we'll have a lengthy chat about it all no doubt.
Different dynos will give different readings, amongst other factors and the last dyno reading this bike had was on a dyno jet at 112hp naturally aspirated. This one ia dyno jet also I'm pretty sure. So a gain of 50% at 7lbs is somewhat unusual, not that I'm complaining.

Just wanna go for a ride

[Yella]

You need to post up the dyno graph

[latheboy]

"So a gain of 50% at 7lbs is somewhat unusual"

Nope that's about correct.

The rule of thumb is, push in 1 bar (14.7PSI) and you will double the HP.
That's only if the moons are aligned and you got everything spot on.

I got 45% extra for 7PSI so I'm close to the magic number.

Pics of the bike and a graph would be good.
Make sure the graph has AFR on it.

[Richd]

1 bar will theoretically double the horsepower but rarely checks out like that, usually ends up being about 80% increase, in my findings. Due to adbiatics, belts drive loss, density loss etc. But shit I'm not complaining. I've got no intercoooler, decomp using barrel plates and didn't expect 50% at just under 0.5 bar.
One change I made from the previous build was widening the lobe centres from 105/108 to 114/116. May have helped

There's a vid of the bike running in the build section and will post the dyno graph with the details

[TurboKat]

How much torque before & after? The thing should be able to tow a B Double now...
What's a adbiatic?

[Richd]

I'll have to dig out the old dyno graph for torque figures but hp went from 112 to 168. I'm heading there RIGHT NOW to pick the bike up. Working on this thing for over two years this is the moment that it's all about.

Adbiatics is the element of heat expansion caused by the compressor creating an air density change. Centrifugal compressors have less of an adbiatics change than screw or roots compressors. Roots being the least efficient.

This is gonna be fun.....

[latheboy]

Where did you get it tuned?

Just noticed you're in Vic..... who was it?

[Richd]

Torque is now 122ft/lbs up from 73 when it was stock. The joint who dynoed it is a mob called Ghostriders in Hoppers Crossing. I was mildly perturbed by the amount of Harley's in there when I first rocked up, glad it didn't put me off. The dyno man ,Romi, a big Romanian bloke was spot on. We had various chats during the process on what wouldn't work, what alternatives there were and how it should play out. A straight talking non bullshitter who was just plain interested in getting right, which he did.
It isn't cool to rag on bad experiences but I've really dug up some A class apathetic too cool for school cocksuckers during this build and to finally get it sorted out is awesome in the least. Top job Ghostriders.

So after going through the whole caper with Romi I donned the leathers for squirt number one and the ride home, this was about 3 hrs ago.
It took a while to find an opening on the freeway and just flattened it in third to top gear. Yep she's quick. First time I'd ridden a properly tuned boosted bike and the torque shove was turning me into a childish idiot.
I really want to mess around with the suspension and get it dialled in a bit more before doing any uber stupid shit, but that'd be some motivation now wouldn't it?
Weather's getting nice too

[Richd]

That'd be 122nm fool which is 99lbs torque.fool.

[Richd]

And that'd be 89lbs too fool