Thread: fzr boost limit?
11-10-2009, 05:24 PM #1
fzr boost limit?
I am helping my friend start building his fzr. So far he has the same mods i started with:
spacers removed , shimmed .080 front .040 rear
-with this this morning it ran 70.4 around 76 deg and humid
-we did the intake manifold upgrade today and put it in the water when we were done. It would only run around 69.7 @7450rpm. It was a little hotter at around 85 deg. but I was expecting it to pick up still. It made a huge difference on my ski. Is it possible it is overboosting the stock ecu now with the flow increased from the man upgrade without the powershot? It does kinda feel like it levels off up top.
11-10-2009, 08:35 PM #2
11-10-2009, 08:40 PM #3
What's the RPM with the CFM kit installed? Prior to that the RPM was a touch low needing maybe a 13/23 pitch on the impeller. I didn't really NEED a 13/24 I think until I had a c3 wheel. Then I had rpm limit 'issues' to solve.
Also, seal the intake grate with 5200 or expanding foam and also install a pump seal kit. Pretty cheap stuff there.
11-10-2009, 09:30 PM #4
11-11-2009, 03:57 PM #5
11-11-2009, 04:17 PM #6
same day, morning to afternoon. It did lose about 100 rpm on top. We are going to run it today. He did tell me he put 89 octane for the first time. We ran it on 93 and then he put 89 in it. Not sure if the ecu is seeing detonation and pulling timing? We are putting 93 and trying it tonight.
11-11-2009, 04:52 PM #7
Your problem is all RPM related. You are about 150 rpms too low. You want to be right at 7600.
Doing the manifold upgrade should in no way reduce the performance of the ski. UNLESS, maybe you installed the sleeve backwards. Is that possible or are you 100% positive you did it facing the right direction?
11-11-2009, 05:03 PM #8
I am 99% sure it is installed correctly. This is the second one I have done and the riva sleeve has a large arrow on it. If all else fails we will go back in to make sure but as of now I am grasping for answers. It does feel better low and mid but just lost that topend rpm of around 100-150rpm. I was pretty sure the fuel didnt matter but it was something that changed so had to throw that out there. We dont have a boost guage on the ski so I am not sure if we have a boost leak. It runs too good down low and mid to have a boost leak I think. It sure seems like it is only on topend.
11-11-2009, 05:07 PM #9
I would have to guess it's hitting the boost limiter.
Most of summer i ran mine with riva air intake,freeflow,ribbon still in and .93 washers under plate. Consistently ran 70-70.4 with 1/4 tank. No problems with boost or rev limiter.
When the temps went down to the low 70's and the water in the 50's. It started hitting the boost limiter. At WOT the ski would start to jerk, but the rpm's would stay solid according to stock gauges.
My buddy has an 08 sho that we've done a few things to. It ran 66 stock.
Installed riva air intake, freeflow. Ribbon still in. It ran 68 with no signs of limiter problems.
Removed ribbon, next time out i watched as he did a run. I could hear the ski hitting the rev limiter(and i assume boost limiter) for a 1/4 mile down river. It sounded like a pack of firecrackers going off.
I felt bad for him. He was quite disappointed when he got back and the gps was at 66 again. He lost his 2mph gain from hitting the limiter. It amazed me that he said he couldn't hear his ski breaking up on the limiter. I could hear it his entire run.
He's at that crossroad now that he has to decide what he wants. A prop to keep him at a stage 1 or invest another $1k and move up to what i'm running.
He's got all winter to think about it.
11-11-2009, 05:11 PM #10
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