[66droptop]

It's time I get my turbo 900RR tuned. It's taken me just short of forever to get to this point. Anyways, I was wondering how much power it'd take to run into the 8s. If I could clip an 8.99 I'd be thrilled.

The bike should be at the same weight as stock from the factory, 438lbs wet according to Sport Rider. I'm 180lbs, so figuring 190ish with gear. To be conservative, I figured bike + rider to be about 650lbs. I've got a front lowering strap and 60" Pingel wheelie bars that also includes an adjustable length strut that replaces the rear coilover. So the bike will be slammed and pretty much wheelie proof. For now I'll still be on my street tires (Metzeler M1s) so traction might be touch and go.

I'm trying to figure out a dyno goal so we can dial in the boost and tune it for that. I think it'll clear 200whp without much problem. I've got a really thick Cometic head gasket. A guy in Sweden was running lower c/r pistons and a thinner head gasket and was making 260whp with his turbo 900RR. So who knows what the bike can take. But I'd really like to run 8s before it pops. What will it take?

[SilverBullet]

Around 220 rwhp. You should also have lower compression pistons also along with the thicker head gasket...you would be able to go with higher boost.

[turbochachi]

What times are you running now

[turbochachi]

Sorry forgot to ask you
how much boost

[66droptop]

220whp huh? This might be close.

I used to run high 10s at 127-129mph, but it's also a gajillion degrees here in AZ. Haven't run it since the turbo setup and I haven't run it with the wheelie bars. I'm looking forward to flogging the bike with the bars on!

Just finished the bike up tonight, so time to get it tuned and dial in the boost.

I'll keep you all posted. Thanks!

[SilverBullet]

My 184 rwhp will only give me 9.20's....so 220 should put you under 9 seconds.

[SilverBullet]

Our Busa with 221hp went a 8.89 on motor and @ 247hp it went an 8.61.

[66droptop]

Eggggggggsellent!


Much appreciated!

[Six_Shooter]

Originally Posted by SilverBullet

Around 220 rwhp. You should also have lower compression pistons also along with the thicker head gasket...you would be able to go with higher boost.

I'm new to bikes, but not new to engines and I see this thinking FAR too often.

More boost does not equal more power, there are several reasons:

When you lower the compression the quench is usually also reduced at the same time, making the complete burn less effective or efficiant, causing less overall HP to be created, even at higher boost, or at the very best same HP level.
There is a limit to how much flow through the intake/carbs/throttle bodies and heads, beyond that point no more flow happens, and therefore no more oxygen can get into the cylinders, and if you are already at that point, then by lower the SCR (Static Compression Ratio), you will only lower overall output level. This will also explain why a ported set of heads will make more power while having less boost level (PSIG).
Lower SCR should be left in the 60's where the use of lower SCR was to combat pre-ignition, which was the only way kown back then, due to less advanced technology. With todays technology and EFI tuning for combating pre-ignition and detonatation can be MUCH more effective. also combustion chanber and piston top shapes can help influence complete burn with less detonation.

[khoanguyen1983]

ummm... word?