My throttle response isent what it used to be, what can I check on my sled? What causes throttle response to get worse?
Throttle response
- Thread starter CHARIOT OF DOOM
- Start date
My first guess would be reeds......
Reeds
Just put a brand new set of reeds and new reed cage in.
i just installed my kit, had about a mile on it and hit the rev limiter and boom a big backfire. I have the tdr reeds which still look perfect but the reed cages were the problem. Where the two cages meet with each other there was about a 1/8" gap. both cylinders looked this way, Needless to say these cages are whimpy.
Ya just installed new reeds with cages and throttle response is doggy, buddy has same kit and his is crisp
0-265 miles ran amazing no codes, DEEP powder day i turned up boost to 8 from 6. 5 minutes into doing this P 1477 code, ended up being RAVE valve not closing all the way. took to dealer had new reeds and cages installed. Reeds looked fine but there was a 1/16th inch gap from reeds and cages. Installed new turbo reeds (same reeds as before) and new cages. Sled runs awesome on top just doggy on throttle. and p1477 code still triggers every start up.
There are a few different things that could be triggering that code. But it is obviously what is causing your less than crisp bottom end. When you start your sled the raves should get sucked in to fully closed. If they don't it's going to be like you've lost running compression. Pull your black cover off of the raves and check to see that they close when you start your sled. If not you have to check for leaks in your vacuum system that power the raves. Check your valves over closely for any oily mess too, they could be cut or loose. If you can eliminate that possibility, then you need to determine if your solenoid that controls the vacuum and the valve mounted between the reeds are both working properly. When the valves don't close at idle it will act exactly like bad reeds. Tough starting, rough idle, sloppy bottom end. Start the sled once you have your rave cover off and listen to how rough it idles, then press the raves down by hand to the closed position where they are supposed to be and listen to the idle. It makes a HUGE difference. Good luck!
Took black cover off rave valve, started sled I then pushed on the rave valves and idle smoothens out like you said!! I push them in probably at least 1/4 inch. This could be my problem if I understand you correctly. I need to find why it's not sucking them in all the way correct?
Yep, check all the vacuum lines going back from your valves. They are the black lines that go back to your solenoid and tie into the clear lines with "springs" in them. From there they go to a white valve sitting between your reeds on the case and from there into the crankcase where it picks up the vacuum. Even a pinhole will do it. Check very closely or if you have a vacuum pump/gauge you can check to see if it is air tight.
How much of a vacuum does it take to suck them closed? It's probably closer to half inch when I push them in
Perform the exhaust valve calibration using BUDS or CanDooPro using a vacuum/ pressure gauge if the valves are in question. Also use BUDS to calibrate TPS and throttle opening %. Once you know all these are correct, it narrows down the possibilities.
Maybe throw in new plugs, they can go bad and do often on turbos, especially if you run leaded fuel. It seemed like plugs lasted 2-300 miles on a buddies turbo etec last year. New plugs and all was well.
Maybe throw in new plugs, they can go bad and do often on turbos, especially if you run leaded fuel. It seemed like plugs lasted 2-300 miles on a buddies turbo etec last year. New plugs and all was well.
Is there any reason they would lose their calibration? That would be great if a simple calibration routine would fix the problem...
Not sure what your buddy is running for a kit and fuel, but I had 500 miles on my plugs when I changed them out at the beginning of this season and they looked new. Just an fyi, not arguing with you.
*forgot to mention, I run 100% 100LL.
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I don't know for sure if they can lose calibration, we check them when we do bigbores and they are always off a small amount....probably not enough to cause any problems. If the diagrams aren't holding vacuum, they may not be staying sucked in at startup..?? See if they hold vacuum and pressure.
My buddy has run different fuels, really not sure what he ran last year. The plugs didn't look bad, but a fresh set always worked for him. Easy item to try and eliminate from the list anyway.
My buddy has run different fuels, really not sure what he ran last year. The plugs didn't look bad, but a fresh set always worked for him. Easy item to try and eliminate from the list anyway.
That is the other thing my dealer did is out new plugs in it, something about let years plugs were working better then this years?? They must be different a little.
Did you find out what was causing the powervalves to stay open during start up?
I found what mine is, waiting to confirm a couple others. Short story is keep these things off the rev limiter! All of them with this problem have that one thing in common, rev limiter, backfire, and fubars your stock check valve mounted on the case between the reeds and it can't send enough vacuum to suck them shut at idle. $33 bucks later you are good to go. You can check the integrity of this valve by taking the clear vacuum line off the bottom of your solenoid and blowing into it. If you can, it's shot. I don't know about any of the other kits, but the Impulse makes boost very quickly, so if you are normally pulling anything over 8050 rpm or higher at WOT, you're pulling too many r's. It won't get you on a long straight pull, but put it into some gnarly terrain where you are on/off throttle a lot, and you happen to pin it just when your track unloads over a hump and it'll ruin your day. I crushed my PTO side cages early last year doing that very thing. By the end of the season last year I noticed a very slight bottom end burble. It threw the 1477 code the first ride this year. Stoked to get that full Impulse ripping bottom end back!! I've kept my top end target at 7950-8000 since I replaced my cage and it runs great.
