I am just beating myself up regarding tire size and final drive ratio's. When towing my 5'er, I will get some pretty serious turbo bark if I drop down to around 1950 rpm while climbing a hill. I have added alot of hp since the last time I towed the trailer. What do you think will happen if I was to go to a taller tire, thereby lowering my final gear ratio? What do you think would happen, say if I was to try towing under that 1950 mark,, or is there anything else I can do to stop the barking?

Any thoughts on this would be greatly appreciated


Kevin

 

Well if I read your signature correct you already have bigger tires. Bigger tires did not stop my barking. The only thing that stopped my barking on the street was installing a BD BOV. A little expensive, but it stopped all the barking when letting off or down shifting. The only time it still barks is WOT locking up in 4th occasionally. With the money you have in mods seems like it might be a solution.

 

Keep the RPMs over 2k while towing. I have no surge or bark even with my big ole A5k if the RPMs stay up and keep airflow moving. I bet you will get better towing mileage to at 2100 than 1900.

 

Thats kinda what I have been thinking, the main reason I brought this up was that someone mentioned something to me about peak rpm range, so I was worried a bit about it..... hey ram, can you tell me more about the bd bov, I have to admit that this is the first I heard of it. And yes I do have 285 70 17's right now,, I am just scared of going bigger, even though I know that looks wise it would be nice to go to a 33" 20 tire

Kevin

 

I have a BD Performance Turbo Guard or BD BOV(blow off valve) installed. PM me with your email and I will send you details and links. I seem to break rules that I don't understand when I post links to products or pictures. Trying not to do something wrong.

 

Don't be afraid...

35's are the perfect final drive ratio w/ 3.73's. 37's w/ 4.10's....

Just drive faster!

 

BTW...that is surge...not bark your describing while towing at low RPMs and I don't think that the BD is a great solution for that.

 

kev, the best way too stop the bark is too put a muzzle on it, thats what i do with my dog anyways!! LOL

 

Well I do agree that 35s and 3.73 gear produces a great highway gear ratio. I also agree that the BOV will not stop surging. It is only going to stop the barking that is produced when heavy acceleration and boost is interrupted by quickly letting off on the pedal. This use to happen to me everytime I got on a freeway, tollway or tried to quickly merge into traffic flow. The BOV stopped all of that barking.

 

This is definately not surging, it is bark, same sound when it goes into overdrive under moderate throttle. With my present setup, pulling the trailer at 70mph it is around 2300rpm,,, no problem,, but when i hit the mountains, which is pretty much everytime I really want to go anywheres,, it will just bark like crazy when it drops to that particular rpm

Kevin

 

That is surge. Rolling onto the throttle at lower RPMs with a load...with a larger than stock turbo...= surge. Keep it sounds the same as a bark...but keeps barking. That is surge.

Barks go away after a couple...like your converter lockup example.

It basically is the same thing...caused by big drive pressure from lots of fuel...bigger turbo pushing lots of air...and not enough RPM's or "engine airflow consumption" if you will which stalls the compressor wheel out for a split second.

 

Cool, I am learning something new everyday. So anything that i can do for that?

Kevin

 

A turbo with a smaller exhaust housing to keep the compressor speed from getting to close to the stall speed, or tow at a higher RPM. If you went to 35's you could downshift and pull the hills in 3rd at 2400rpm and be around 110km/h.

 

my problem is that I have too much power to run in 3rd, it will just over rev,,, I can allmost pull most hills in overdrive,, and maybe even now with the extra hp I might even be able too

Kevin

 

Then just speed up and run 2k plus in 4th.