Really cold weather twin question

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YEA WE RIDE THE SHORT BUS
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Nov 22, 2007
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For the guys that have run twins longer then i have:

Has anybody ever noticed any difference in how your twins act when its really cold outside? Below 20*. I have 64/65 over HT3B. Back when i ran the 64 by itself it use to surge like a B***h but when i put the HT3B under it back in the summer the surge went away. Here for the last month or so its been real cold here and the truck has gone back to surging in high gear with the chip on all levels as you excelerate at a decent clip, not the clutch slipping either. Once the outside temp raises to 35-40* the surge goes away. Any body else had this happen or heard of anyone having this problem, Thanks Jeremy
 
sounds like a fueling/timing issue my 24v with a 66/71/14 surged bad above 3k rpm
 
Are you running an edge comp on it? It seems that it appears to be in the freezing area? Shut the comp off and see if it goes away.
 
i know my twins tuck up and hide around 30 or so degrees. its amazing yours work at all!
 
All of you guys are from some place warm, it was -17 this morning. Currenlty twins in my garage but the only difference you should see is a faster spool up.

My truck scared me a little yesterday, at 1degree with as much fuel as I have it was literally almost instant boost. So at 65mph it decided to cut lose and side step towards the edge of the road.(Mag on the roads makes them very slick in the winter)
 
01 and 02's seem to be more susceptible to this on the VP44 trucks. The timing maps get a little crazy with cold IAT's and OAT's. If you run large injectors, they can really develop a surge, especially if you run a box that has timing. The more "slack" you have in the drive train (like running a detroit locker) the worse if will feel. At one time there was a long thread over on TDR about this subject. Nobody really came up with a fix for it. For some, fooling the IAT works, but not for everyone. Fooling the IAT causes problems with the grid heater. For me running low timing with the smarty and stacking it with the redline box works the best. Running the ADR is the worse.

Paul
 
zstroken said:
Are you running an edge comp on it? It seems that it appears to be in the freezing area? Shut the comp off and see if it goes away.
Click to expand...

I have a TST Comp and it only does it below 30*. Ive tried it with the box off with it on level 1 ive tried evey level and it continues to do it but only in 6th gear.

paulb said:
01 and 02's seem to be more susceptible to this on the VP44 trucks. The timing maps get a little crazy with cold IAT's and OAT's. If you run large injectors, they can really develop a surge, especially if you run a box that has timing. The more "slack" you have in the drive train (like running a detroit locker) the worse if will feel. At one time there was a long thread over on TDR about this subject. Nobody really came up with a fix for it. For some, fooling the IAT works, but not for everyone. Fooling the IAT causes problems with the grid heater. For me running low timing with the smarty and stacking it with the redline box works the best. Running the ADR is the worse.

Paul
Click to expand...

The IAT seems to maybe a logical idea with it being as cold outside as it is, but i had a 66/71 on it last winter and it didnt do it. I run 150 sticks The reason i asked about the twins is it does it at the same boost as the 64 did the surging as a single and was wondering if the colder air being compresed when it enters the 2nd charger maybe messing with the compressor MAP since it would surge on its own. Thanks for the help guys.
 
I have 0 issues with surging all so .My only concern is there is almost no way to keep the boost low untill the engine warms up,got to be testing the head gasket.This is a CR too.
 
are you saying the TRUCK is surging or the TURBO is surging? :confused:

if you're talking about the turbo, the reason your 64 surged is because it's a mismatched turbo w/ the little 65 wheel... the reason it went away when you hung the 3B under it is because the turbo was now having to inhale through the 3B's compressor and exhale through the turbine, so it effectively slowed down the spool-up of the 64

what does a turbo do? it pressurizes the air, which increases air density...

what characteristic does cold air have vs. hot air? density!!!

when I wrote the map for my VNT controller, we were still in the 90's... now that I'm in the teens and 20's, I've had to turn down the duty cycle to stay out of surge.

the cold air has added enough density to push your compressor back to the left of the surge line.

moral of the story? 68 or 71mm turbine for your 64 IMO
 
try unhooking the box all together. i got to thinking about it and last winter i was running a adr/smarty and the winter befor i had the drag comp/smarty.
 
I believe forrest is on to some thing my turbine is a 73 on top that would explain mine not surgin as well mine did spool great and egts stayed cold as heck as well
 
My twins act fine the vp not so good in this below 0 weather we are having. It's almost like the pump is going out most of the time. I wish I could have this kind of spoolup all the time!
 
Forrest Nearing said:
if you're talking about the turbo, the reason your 64 surged is because it's a mismatched turbo w/ the little 65 wheel... the reason it went away when you hung the 3B under it is because the turbo was now having to inhale through the 3B's compressor and exhale through the turbine, so it effectively slowed down the spool-up of the 64
Click to expand...

That's my suspicion as well.
 
Forrest Nearing said:
are you saying the TRUCK is surging or the TURBO is surging? :confused:

if you're talking about the turbo, the reason your 64 surged is because it's a mismatched turbo w/ the little 65 wheel... the reason it went away when you hung the 3B under it is because the turbo was now having to inhale through the 3B's compressor and exhale through the turbine, so it effectively slowed down the spool-up of the 64

what does a turbo do? it pressurizes the air, which increases air density...

what characteristic does cold air have vs. hot air? density!!!

when I wrote the map for my VNT controller, we were still in the 90's... now that I'm in the teens and 20's, I've had to turn down the duty cycle to stay out of surge.

the cold air has added enough density to push your compressor back to the left of the surge line.

moral of the story? 68 or 71mm turbine for your 64 IMO
Click to expand...

Yea, I know it needs a bigger turbine, but just through it on there because thats what i had laying around.
The truck is surging. But It does at the same boost pressure as the 64 did as a single. When the 64 surged as a single it would make the truck surge slightly. Thats why i was leaning towards it being a turbo problem. Had it on the dyno today and it was 50-60 degrees in the shop and it didnt surge at all pulled it back out side and headed home it started surging again as we excelerated on the highway:bang
 
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