changing out my old plastic mcx APEX BOV/ IC bov?

[Octanee]

hey guys, So I had my first somewhat... Ok season with my apex as the sled it can be. upgraded the track and did the clutching right... Only thing I'm missing on my clutching is the rollers. But I'm still having some good ol turbo lag, getting into boost and the on off throttle can be a bit slow coming back in. when boost starts to climb it hits hard and usually bounces off the rev limiter once or twice until clutches catch up. I'm thinking its due to the stock rollers which I have yet to replace. I also have a CR racing intake.


on off the throttle theres some but once your up and away its alright. My exhaust should not any any leaks really. I had it all apart when I did my track and I welded all and any cracks in my SS y pipes. I put copper donuts in and all them goodies

I don't have a boost leak as far as I can tell either. it responds to my boost T when adjusting in fine amounts and reaches peak boost quickly and sustains it. I did have a couple over boost times last winter. Climbed a hill and it was bouncing off the rev limiter, did a second run and seen it wanted to climb to 20# or more... Its a 290 hp pump gas kit so I know boost should be 15-16# depending.

I ride with a guy whos got the newer MCX kit on his 07 or 08 MCX apex which responds much quicker. and one thing I notice in the newer kits Is they have a much better BOV and it also gives off some Flutter even under very light throttle and letting off which I know could be turbo surge and/or it holding some positive air pressure in the charge tubes.

Now I have 2 Bov's. the plastic one under the headlights and one on the side of the I/c. I was thinking maybe I could increase my responsiveness would be changing out the plastic BOV? I've heard lots of people say they freeze up and have a lot of issues with them?. I'm thinking if i go to a billet style one and get it to hold in a WEE bit of pressure, ~1 psi? so I'll get a little flutter maybe that's all I need to reduce my lag. So It wont completely dump pressure on and off the throttle it will hold a little so when I open up the throttle in the trees It'll be more "ready to go" vs having to start from scratch almost in vacuum to positive pressure for the brief moment?

also the I/c BOV, Do people keep those? are they in the newer MCX kits? having a dual BOV design?


I know that if you have positive pressure or too much it could cause the sled to continue to run on when the throttle blades are closed as its forcing air by them still and fueling for it.

thanks for any ideas or recommendations on it all! look forward to hearing opinions on it all

 

[M5-]

What are you geared at? Most of the guys I know have switched down to 18 40 with a 174 and 19 40 at 162.

M5

 

[BOOSTD]

I believe the apex mtns were suppose to come with the 14.5mm roler, I don't have the book in front of me but that should be the proper size your looking for. What clutch setup do you have right now? Lots of apex guys here that could help you out with that.

You can also run a bov on your actual compressor housing, it works really good and is at at the wheel so prevents most any surge issues. I've been running mine there for a few seasons with great response and no flutter.

 

[zebiraross]

What do you have for clutching right now?

 

[M5-]

I only run the one BOV on the intercooler on my MCX Nypex. Can you hear your BOV leaking, if not then it shouldn't even come into play until you have reached full boost or let off the throttle. What turbo is on there, is it a 19T or a 16T with a remap (which is the old 310 kit).

Like Zeb mentioned list every part of your clutching setup on here so we can see where you are at.

M5

 

[Octanee]

I only run the one BOV on the intercooler on my MCX Nypex. Can you hear your BOV leaking, if not then it shouldn't even come into play until you have reached full boost or let off the throttle. What turbo is on there, is it a 19T or a 16T with a remap (which is the old 310 kit).

Like Zeb mentioned list every part of your clutching setup on here so we can see where you are at.

M5

Thanks for the replies guys!

Alright the clutching. I looked back at a old thread I made and It sounds familiar to what I put in. 47 straight helix, EPI Purple with spring clocked I think something like 0-2? Its really hard to twist and pop it back on the threads to tighten down, I mean real hard.

In the primary: Blue/white/blue spring. dalton weights cranked to their max so maybe 88 Grams or something, I'm thinking I got their heaviest kit which on their site says 84-92G so I could be 86G from their lesser kit or at 92G approx. I loaded them up all the way. 14.5MM rollers was recommended to me But again I never changed the rollers in the clutch at all so they are still stock, which may be the wrong size for boosted application? not sure what stock is for the 06 apex mtn

And the gearing I believe to be stock. I purchased the sled with some upgrades already on it which is stupid to think that it had a timbersled skid with stock track, and half lugs ripped off lol, She spun out to about 150KM/H climbing a hill and didnt go anywhere! so I'm going to say its Stock gearing too. I now have the 174 2.5" track on it.

And blow off valve, I don't hear it leaking and it does seem to work as intended however It's so quiet, I'd like to make it louder. I love that light fluttering and or blow off sound you can hear on some sleds while they are up climbing a hill and on off the throttle. Mine is dead silent and when I hear it dump it does a pfffff like just air released. I'm thinking that with the newer kits they make that noise as perhaps its a tad of turbo flutter because maybe they hold a little pressure as I was thinking earlier so that when you hit the throttle its not starting all over again? which would help it get up and wind out quicker?


Also I was reading into the mcx apex kits and their parts pictures of their complete kit off their site. I see no mention of a plastic external BOV, or visually? just one on the "plenum" or the I/C which mine does have one there. So maybe Mine has an additional Bov? It's installed on the rubber hose from the tunnel cooler running up to connect into the I/C. Maybe it is stock with the old MCX kit? Mine has the tuna fish can box I think its known by. also no altitude compensation for boost or nothing, Deff one of them first gen kits as its a 2006, first year of the apex mountain?

Thanks again for replies! I'm looking forward to hearing what you guys would advise. Thanks

 

[M5-]

If it were me I would nail down the clutching specs exactly. The stock Apex had 16.5 rollers. If you have the old POS tin can controller (which are crap) you in all likely hood have a 260 kit with a 16t not the larger 19T. MCX offered a 310 map upgrade for the 16t but it made tons of heat. The 16t spools up quick but it just cant move the air so it will take longer to build to max boost. After 12 lbs its just making heat not power.

Being that you are running a 174 I would drop the gearing to 18 40. Some guys will argue this but it saves belts and helps bottom end. If you do change out the gearing you may be able to turn down the boost a bit as you are mostly just making heat anyways plus as an added bonus you wont crack headers.

I think that gearing and clutch tuning are your best bets and run the kit within its design parameters. A 16t at 17 lbs is just that a 16t at 17 lbs. Mcx went to the 19t for a reason.



M5

 

[Octanee]

If it were me I would nail down the clutching specs exactly. The stock Apex had 16.5 rollers. If you have the old POS tin can controller (which are crap) you in all likely hood have a 260 kit with a 16t not the larger 19T. MCX offered a 310 map upgrade for the 16t but it made tons of heat. The 16t spools up quick but it just cant move the air so it will take longer to build to max boost. After 12 lbs its just making heat not power.

Being that you are running a 174 I would drop the gearing to 18 40. Some guys will argue this but it saves belts and helps bottom end. If you do change out the gearing you may be able to turn down the boost a bit as you are mostly just making heat anyways plus as an added bonus you wont crack headers.

I think that gearing and clutch tuning are your best bets and run the kit within its design parameters. A 16t at 17 lbs is just that a 16t at 17 lbs. Mcx went to the 19t for a reason.



M5

thanks, Alright so rollers for sure, And I'm not sure about the kit?. Because I installed a a/f gauge on the sled as advised by the guys at mcx because it was a ?? on what my sled had for a kit. and they told me to crank my boost up until I reached a 11:0 a/f If I remember right. and I can run about 15-16#. I'd love to drop in a 19T into the sled as I've heard that at 15# you will make like 30 hp more from efficiency. but as it stands it's slow to spool. And I don't have a 19T according to MCX who asked me to check the plugs on the turbo? saying 1 plug meant 16t and the 19t has 2 plugs?


Also my kit had a switch in the back if that helps any? It was T'd into the wastegate so that it would let some air seep out if you flicked it the one way?. Also I was told the guy used to do some big chute climbs with it so I'm not sure.


I asked MCX how much a 19T was and they tried to tell me something like $1600, I'm like F that... you can buy a BALL BEARING garrett turbo that will flow better and more effeciently for cheaper. Hell I got a 2876 sitting waiting to be sold. But I'd rather not do much modding, I'd like a direct drop in replacement though and i know my 2876 will never fit in there LOL :face-icon-small-hap

 

[M5-]

Last time I checked Alamo in Calgary would convert your 16t to a 19t for about 500 to 600. They install a new CHRA and machine everything. Im assuming you have a manual boost controller. Have you pulled the box off and had someone check what map is in there?

M5

 

[Octanee]

Last time I checked Alamo in Calgary would convert your 16t to a 19t for about 500 to 600. They install a new CHRA and machine everything. Im assuming you have a manual boost controller. Have you pulled the box off and had someone check what map is in there?

M5

Sorry for a delayed reply, and oh really? Well I should look into that! And no I have not, it looks like a real head ache wires run up into??? Well I mean I know where. It's a shame they did not put connector right after the box to make it simple to unplug it and ship it. But talking with the mcx guys they figured I may of had the older higher horse kit iirc. And I ran 15# lower down then about 17# higher up with the limiting factor of my clutching wanting to be bouncing off the Rev limiter so I must need smaller rollers. I was running a 11:1 a/f or lower if I remember.

And another guy I run with had a 08 apex with the 280 or 290 kit and auto altitude compensator, my boost was in line with his.

Say by chance do you have any specs for the 19t? Maybe I could measure mine just to see if I may already have a machined turbo, it may be a reason for my increased lag?


Aside all that it's been a good few months I can't remember, I won't get my sled til mid November so until then I'm just going off my memory but I'm planning ahead on how to improve it! Thanks again for the replies!

 

[M5-]

I'm just going from memory here so take this for what its worth, you'll have to use google and search it out yourself to get the exact info, but there are a few differences between a 16t and a 19t. If you are talking Garrett turbos then everyone knows a gt25 exhaust turbine housing is smaller than a gt28 and a 54 compressor is smaller than a 60 or a 71...... What gets measured there is the A/R. In the Mitsu world the A/R is referred to as a 6 cm vs 7cm housing. The 19T uses a 7cm housing and the 16t uses a 6cm, there are also different styles of compressor wheel available. You can build a 19t from any 7cm housed turbo in the family by changing the compressor side housing and putting on a new compressor wheel and having it balanced, this isn't a DIY job. In fact I was going to do just that so I bought a 15G with the 7cm housing I think its somewhere in my shop if you are interested I'll sell it for $150 which is what I paid. Anyways you will need to do your homework but like I said before if you are spec'd as a 16t 12lbs is it the rest is just heat.

M5

 

[Octanee]

I'm just going from memory here so take this for what its worth, you'll have to use google and search it out yourself to get the exact info, but there are a few differences between a 16t and a 19t. If you are talking Garrett turbos then everyone knows a gt25 exhaust turbine housing is smaller than a gt28 and a 54 compressor is smaller than a 60 or a 71...... What gets measured there is the A/R. In the Mitsu world the A/R is referred to as a 6 cm vs 7cm housing. The 19T uses a 7cm housing and the 16t uses a 6cm, there are also different styles of compressor wheel available. You can build a 19t from any 7cm housed turbo in the family by changing the compressor side housing and putting on a new compressor wheel and having it balanced, this isn't a DIY job. In fact I was going to do just that so I bought a 15G with the 7cm housing I think its somewhere in my shop if you are interested I'll sell it for $150 which is what I paid. Anyways you will need to do your homework but like I said before if you are spec'd as a 16t 12lbs is it the rest is just heat.

M5

Thanks again m5, I have not seen a 15g, would it's compressor be a kinda bolt on solution? And to make sure I'm getting it right, the 19t has a bigger exhaust as well as compressor correct? Or is it just a bigger compressor? And yeah I know it makes big heat after 12#, I did about a 40 second pull before with it, stock track so a hill that would take me 20 secs took 40, amd re watching that video I can see all the snow. Melt and turn to steam on the front intercooler lol! And the turbo otherwise I may be interested but it won't be for a bit. I have to still figure out as it stands my boost lag. But I would like a better more efficient turbo than the heat maker of course.. So time will tell

 

[Octanee]

I called Brad at mcx, and he says I shouldnt/the kit never had another bov. So I'm going to remove the spare plastic one to see how it behaves. It might fix my slower boost issue, and the 14.5mm rollers, then that I hope is my ticket, if not then what ever lol and a turbo down the road... Now to wait another month to month and a half for the snow to test it.