GSX-R600 Intake Explosion

[Mindwalker]

We are using a 2001 Suzuki GSX-R600, and we keep having intake explosions. We are using a Dual Plenum design. We are injecting fuel pretty much straight at the cylinder, but still have violent explosions. If anyone knows anything about this, please let us know! Also, does anyone know what pressure we should run the stock injectors at, that would be great too.

Thanks
-Mindwalker

[Mindwalker]

We are using a 2001 Suzuki GSX-R600, and we keep having intake explosions. We are using a Dual Plenum design. We are injecting fuel pretty much straight at the cylinder, but still have violent explosions. If anyone knows anything about this, please let us know! Also, does anyone know what pressure we should run the stock injectors at, that would be great too.

Thanks
-Mindwalker

[Kirk Feldkamp]

Mindwalker,

1. Are you sure the crank and cams are in sync physically?

2. Are you sure you have the cam and crank in sync in your FI software? (CRIP in the MoTeC)Check it with a timing light. What FI system are you using?

3. Are you sure you have the correct firing order?

4. Does it run, but backfire? Or does it just backfire and not run?

5. Where is your ignition timing at?

6. Did you check to make sure the injectors are really set up as the correct cylinder? It can be done using either the cylinder # or in firing order on a sequential system.

7. Stock fuel pressure is 42psi. But that's not the problem.

We're rockin' the GSXR6 also, and we went through the same problems on the first setup too. Any pictures of the setup you could share with everyone?

-Kirk

[Patrick W. Crane]

ya, we are doing the gixxer thing as well. If the car won't run at all you might have which cylinder is 4 and which is 1 mixed up. It creats a few problem... haha OOPS

[Mindwalker]

http://mindwalker.8m.com/intake_UofI.JPG


Here's a picture of our prototype intake - the actual intake is of aluminum - slighly different design, but the same results on explosions.
We have the engine running well actually. It just seems that after we kill the engine and it's warm, then we let it sit for a while, then try and start it; then the intake blows up. Almost like a perfect gas mixture is vaporizing inside the intake as the warm engine sits and evaporates the gas, and then when we crank it over - a perfect little bomb as been created It does do some backfiring on startup - but once it runs it's pretty smooth. Our ignition timing may be an issue - though we've fooled with that aroun 50 -10 degrees BTDC, and doesn't seem to change things. Our firing order is correct. Our CRIP at 462 I believe - we did the timing light thing twice - and we think we're close there too. HMMM . . .

[CMURacing - Prometheus]

is the fuel rail somehow dumping all its excess fuel into the intake and not the return line on fuel pump (ie master power) shutdown?

[Dan Deussen @ Weber Motor]

Intake backfires can be due to excessive amounts of spark advance during engine cranking with the starter. Try setting your advance around 5 degrees at 0 rpm and ramp it straight up to 15 at 1000 rpm.

[BryanH]

Hot start is too lean. If your ecu has post start enrich, enable it at all temps and make sure first few seconds are around 25to 30% enrich.
If you don,t have this feature make sure initial prime at hot start is 15-20 m/sec AND richen up the zerorpm load points to eliminate the lean condition.(sorry, I don,t know what you get for $798)
GMDelco set cranking ign timing for waste spark setup at 10deg, & this setting has always worked for me. Seems only engines with valve overlap >270deg are sensitive.

[B Lewis @ PE Engine Management]

I agree with Halfast. A lean mixture burns much slower and given the right conditions can stll be expanding when the intake valve opens. That is why the condition is more prevalent with high overlap engines (like 600cc bike engines). If you are using our system increase the cranking compensation at hot temps and add a little priming pulse (although 15-20 ms seems high for these small engines).