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Intake Boot Spacer Modification for Boost Leak

no1b4me

Pro
Joined
Dec 31, 2016
Messages
199
Location
Ontario
Country
Canada
Snowmobile
2019 ZR9000 Ltd iACT
****WARNING THIS MAYBE LONGWINDED ****
Well let's start, after finally doing a boost leak test due to the odd knock light (3x) one on each tune level last season , I have a leak ! This is on a brand new sled with 0 miles, so it is obvious that the factory spec for clamping force on the intake boots may be suitable for stock power, it is not for any tuned sled. The knock light would only occur on high speed long runs , corner to corner there is no issue of knock light activation.
When I was conducting the test I could hear the leaks at 13 psi , the Turbosmart Kompact BOV has a inherent engineering flaw and will always leak a little from the top overpressure assist , there is no seal/ring on the upper portion of the piston valve so it leaks downward along the inner body of the assembly , the bottom of the valve has a O ring and seats and seals correctly, the leak is minimal which won't cause any performance issue , just a engineering oversight.( partial remedy is to disassemble and coat the piston valve and inner body with a tacky lithium grease ,this will minimize the leak ).
Onward, used a soap solution to detect the source of the leaks , all the intake boots were leaking ! $hit Fuzz !!! I was hoping for easy fix like a loose intercooler clamp or Plenum .... I dreaded this job because of how yamamarc and few others commented on this ugly job.
So , decided to go the ugly route ,though the other route is ugly as well.
I disassemble all the hoses and plenum and a couple of electrical connectors to gain access to the clamps ,remove all the bottom clamp spacers and nuts and the same for the top , just take your time so not to loose the spacer or nuts . The nuts are magnetic however the spacers are stainless steel so they are difficult to retrieve if you drop one on the engine assembly. That was easy , the disassembly part...... I used a good metal file and adjusted the spacers to 0.170 , after speaking with Hurricane Dave,he recommended the removal of 0.080 off the spacers and from the pictures you can visually see the boot bulging due to the additional clamping force.
Reassembly was my anxiety , I started on the MAG side ,figuring let's start EZ....started with the head side clamp and reassembled easily , to aid in spacer install apply a bit of tacky lithium grease into the barrel of the spacer and slide it onto the cap screw, this will prevent it from sliding off. Then went to assemble the TB side of the clamp from the top, got it because it was somewhat accessible .
Now , got brave and decide to do the centre one next, did the head side easily because it again is on the bottom , moved to the top and I said "what the fuzz" now thinking ok need to go to ugly route 2..... then looking at the turbo , I remembered I had to clock my turbo on my Buick Grand National (bigger turbo install) ....then it came to me , the head side clamps are easy because they are all located on the bottom and there is just enough room to get my mitts in there to assemble . So I assemble the TB side clamp from the bottom and clocked it into it's proper position , just assemble all 6 clamps from the bottom and clock them into position , just start threading the nuts about 2.5 threads ,this leaves the clamp loose enough to clock it into position,there will be a bit of resistance during the clocking until it gets into the boot key. For the most part you will be working blind because you can't get your pumpkin into the compartment to see what your hands are doing .
The top centre one literally took me 15 mins , the PTO side both clamps installed within 15 mins.
I have attached some pictures and scribed some details.

TOOLS must have to ease the task
1/4" drive ratchet along with a 14" & 4" extensions
4mm ball end allen head socket 1/4" drive
tacky grease
long narrow flat blade drive to assist clocking clamps.

Now after doing this ugly task , I feel confident that I could do this within 2.5 hrs without having to deal with coolant or fuel spillage ....though minimal spillage , I am OCD and sooner not disturb something that ain't broke ,plus clean up of fluids.

Hope my experience will aid you in your intake boot modification as well.
Cheers
Rob
 

Attachments

  • 998 intake boot clamp mod.jpg
    998 intake boot clamp mod.jpg
    129.3 KB · Views: 1,003
  • 998 intake boot leak.jpg
    998 intake boot leak.jpg
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  • modified 998 intake boot clamp spacer.jpg
    modified 998 intake boot clamp spacer.jpg
    117.3 KB · Views: 892
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****WARNING THIS MAYBE LONGWINDED ****
Well let's start, after finally doing a boost leak test due to the odd knock light (3x) one on each tune level last season , I have a leak ! This is on a brand new sled with 0 miles, so it is obvious that the factory spec for clamping force on the intake boots may be suitable for stock power, it is not for any tuned sled. The knock light would only occur on high speed long runs , corner to corner there is no issue of knock light activation.
When I was conducting the test I could hear the leaks at 13 psi , the Turbosmart Kompact BOV has a inherent engineering flaw and will always leak a little from the top overpressure assist , there is no seal/ring on the upper portion of the piston valve so it leaks downward along the inner body of the assembly , the bottom of the valve has a O ring and seats and seals correctly, the leak is minimal which won't cause any performance issue , just a engineering oversight.( partial remedy is to disassemble and coat the piston valve and inner body with a tacky lithium grease ,this will minimize the leak ).
Onward, used a soap solution to detect the source of the leaks , all the intake boots were leaking ! $hit Fuzz !!! I was hoping for easy fix like a loose intercooler clamp or Plenum .... I dreaded this job because of how yamamarc and few others commented on this ugly job.
So , decided to go the ugly route ,though the other route is ugly as well.
I disassemble all the hoses and plenum and a couple of electrical connectors to gain access to the clamps ,remove all the bottom clamp spacers and nuts and the same for the top , just take your time so not to loose the spacer or nuts . The nuts are magnetic however the spacers are stainless steel so they are difficult to retrieve if you drop one on the engine assembly. That was easy , the disassembly part...... I used a good metal file and adjusted the spacers to 0.170 , the removal of 0.080 was recommended by Dave and from the pictures you can visually see the boot bulging due to the additional clamping force.
Reassembly was my anxiety , I started on the MAG side ,figuring let's start EZ....started with the head side clamp and reassembled easily , to aid in spacer install apply a bit of tacky lithium grease into the barrel of the spacer and side it onto the cap screw, this will prevent it from sliding off. Then went to assemble the TB side of the clamp from the top got because it was somewhat accessible .
Now , got brave and decide to do the center one next, did the head side easily because it again is on the bottom , moved to the top and I said "what the fuzz" now thinking ok need to go to route 2..... then looking a the turbo , I remember I had to clock my turbo on my Grand National (bigger turbo) ....then it came to me , the head side clamps are easy because they are all located on the bottom and there is just enough room to get my mitts in there to assemble . So I assemble the TB side clamp from the bottom and clocked it into it's proper position , just assemble all 6 clamps from the bottom and clock them into position , just start threading the nuts about 2.5 threads ,this leaves the clamp loose enough to clock it into position,there will be a bit of resistance during the clocking until it gets into the boot key. For the most part you will be working blind because you can get your pumpkin into the compartment to see what your hands are doing .
The top centre one literally took me 15 mins , the PTO side both clamps installed within 15 mins.
I have attached some pictures and scribed some details.

TOOLS must have to ease the task
1/4" drive ratchet along with a 14" & 4" extensions
4mm ball end allen head socket 1/4" drive
tacky grease
long narrow flat blade drive to assist clocking clamps.

Now after doing this ugly task , I feel confident that I could do this within 2.5 hrs without having to deal with coolant or fuel spillage ....though minimal spillage , I am OCD and sooner not disturb something that ain't broke ,plus clean up of fluids.

Hope my experience will aid you in your intake boot modification as well.
Cheers
Rob
Awsome write up Rob and smart thinking about turning the clamps to the bottom!!!!!!
Where the heck were you when I did mine....lol
 
There was a article I think from Dave ( hurricane)describing the same thing you written above over on HCS awhile back. Huh!
 
Aghhhh...thanks for reminding me I need to do this on my Winder!
Great writeup

Thanks.... Just did a follow up boost leak test earlier today and the charge system is all sealed up, tested to 24psi....this is inclusive to ignoring the inherent engineering design flaw on the Turbosmart Kompact BOV, coating the piston valve as stated above really helps however there will always be a smidgin of pressure leak.
Based on my test and looking at these intake boots factory clamping spec.... And Hurricane Dave's data collection of boost leak analysis.... I feel very confident that all boosted sleds above stock pressures have boost leak!!! You may not want to agree or experience a knock light , however the spacers are 0.250, mine were all tight against that spec... So theoretically all 998's have the same amount of clamping force, so they will leak above stock boost pressures.
 
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Thanks.... Just did a follow up boost leak test earlier today and the charge system is all sealed up, tested to 24psi....this is inclusive to ignoring the inherent engineering design flaw on the Turbosmart Kompact BOV, coating the piston valve as stated above really helps however there will always be a smidgin of pressure leak.
Based on my test and looking at these intake boots factory clamping spec.... And Hurricane Dave's data collection of boost leak analysis.... I feel very confident that all boosted sleds above stock pressures have boost leak!!! You may not want to agree or experience a knock light , however the spacers are 0.250, mine were all tight against that spec... So theoretically all 998's have the same amount of clamping force, so they will leak above stock boost pressures.

I agree with you 100%
I seen it with my 998 !!
Just look at the leak on your tb
20200926_211757_copy_389x509.jpg
 
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I agree with you 100%
I seen it with my 998 !!
Just look at the leak on your tb
View attachment 156408

Hey Marc , also the factory rubber charge tubes are at their threshold as well on boosted tuned sleds, I can fore see them rupturing at the molded seams , this will be my next safety upgrade !
:jump:
 
I checked mine today at 22psi with soap and water and I got zero bubbling. Like you said, technically we should all have leakage as the spacers are the same size so Im curious why some sleds have issues related to this and others are fine. I have several datalogs ranging from 15-30 seconds at 100% throttle and 17.8 psi. I had an average of .2 degrees of timing retard due to knock which is next to nothing considering I believe you need 2.5 degrees of retard to activate the knock light. My peak boost psi will be lower this year since I am running the header now so I am not going to tackle this project till the day it may be needed,if ever. Any leakage, if any in my case is null. I have never seen a knock light, and dont have an issue with high intake air temps. Could there be a little inconsistency with the length of these spacers that some sleds are getting a better "squeeze" than others?
 
I checked mine today at 22psi with soap and water and I got zero bubbling. Like you said, technically we should all have leakage as the spacers are the same size so Im curious why some sleds have issues related to this and others are fine. I have several datalogs ranging from 15-30 seconds at 100% throttle and 17.8 psi. I had an average of .2 degrees of timing retard due to knock which is next to nothing considering I believe you need 2.5 degrees of retard to activate the knock light. My peak boost psi will be lower this year since I am running the header now so I am not going to tackle this project till the day it may be needed,if ever. Any leakage, if any in my case is null. I have never seen a knock light, and dont have an issue with high intake air temps. Could there be a little inconsistency with the length of these spacers that some sleds are getting a better "squeeze" than others?

So with you coming up with zero boost leak during your test , and if your unmodified spacers are 0.250 ,then there is a possibility of inconsistency in the size of the other components in this assembly. Clamp length ,intake boot OD and ID will all affect sealing integrity, I would like to think the TB and head spigots were casted to spec........
Glad you had no boost leak detected.....just wish it was me :D:D:D
If this task ever needs to get done , it really isn't that bad ..... no big deal.
 
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You only need the regulator if you want to leave your airline flowing at a certain psi. The setup marc is using is the same way I do mine......just pump up to your desired psi and examine for leaks, add some air when it bleeds down. Mine is just a cast pipe cap that I drilled and tapped for a tire valve. The inflator has a lock on it to keep it attached to the valve.
 
You only need the regulator if you want to leave your airline flowing at a certain psi. The setup marc is using is the same way I do mine......just pump up to your desired psi and examine for leaks, add some air when it bleeds down. Mine is just a cast pipe cap that I drilled and tapped for a tire valve. The inflator has a lock on it to keep it attached to the valve.
Yes and don't forget to disconnect the air line and hit the trigger to bleed the air out before removing the gear clamp...lol
It will will blow off like a rocket.....
Ask me how I know......hahahahah
 


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