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Shorty-DD
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Joined: March 10, 2018
Posts: 10
Location: Dresden / Germany
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 Posted: Wed Dec 30, 2020 6:10 am Post subject: 1835ccm Holset Turbo - A/R .82 too much? |
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Hi...i’m in a build of an 1835ccm draw-through Turbo (for Dragrace) and now i need a Turbo. I have a Holset H1C (is the older HX35) but without the turbine housing. I have two housing options:
12cm2 - app. A/R .64 twin scroll
16cm2 - A/R .82 single scroll or twin scroll
1835ccm specs:
69 x 92 tw
40/35 heads
Fk8 - 1:1.4 rocker
Weber 45mm DCOE-Carb.
Rev.-limit 7000rpm
Which A/R is the better choice?
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VW 1600 TL (Typ 3) - 1622cc + 34pict + Turbo = fun |
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madmike
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Joined: July 11, 2005
Posts: 5292
Location: Atlanta,Michigan
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| Posted: Wed Dec 30, 2020 6:58 am Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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The .64 will spool quicker , 
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'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works" |
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BFB
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Joined: November 03, 2014
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| Posted: Wed Dec 30, 2020 8:29 am Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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IF it has the same specs / map of an hx35?.. do you have any idea what an hx35 will do?? if i recall correctly its something in the ballpark of 25 or 30 psi at 800cfm! waaaay more than a vw is gunna need, it might start to spool at 7000 rpms...
my 2276 at 13 psi and 6500 rpm isn't but somewhere around 400 cfm if that gives u some idea.
im all for using what u have and for junkyard turbo builds but theres plenty of engine calculators out there and turbo maps arent that hard to find, do you research and use a turbo that fits your engine & rpm range, youll be happy you did.
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1 |
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buguy
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Joined: November 17, 2003
Posts: 4915
Location: Port Orange, FL
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GARRICK.CLARK
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Joined: June 30, 2012
Posts: 1267
Location: Lancashire UK
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| Posted: Wed Dec 30, 2020 9:12 am Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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| As above. You need to go a lot smaller |
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BFB
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Joined: November 03, 2014
Posts: 1751
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| Posted: Thu Dec 31, 2020 8:03 am Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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dont believe everything you read on the internet they say, and i dont believe that one at all.
i had a 1600 with an old rayjay turbo kit ( same one thats on my 2276 now) and it wouldnt START to spool until 4500 rpm and wasnt full on until 5000 to 5500 rpm. i had to shift that poor stock bastard at 6000 rpm just to enjoy any boost at all. ( well, by any i guess i mean 20lbs heh heh ) but 20 doesnt really take much longer to reach than 10...
same set up on a 2276 and im in the thick of it by 3000rpm.
maybe ol boy put an hx35 on a 1600, but it aint no "1600". is he slinging that thing to 10k? high c.r. to move more cfm and spool the turbo? nitrous? i dunno, but i smell something funky in that kitchen
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1 |
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andor
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Joined: June 21, 2007
Posts: 44
Location: Norway
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| Posted: Thu Dec 31, 2020 10:47 am Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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What size exactly is the turbo? Turbine and compressor wheel?
What hp goal do you have? |
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Chip 
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Joined: July 19, 2008
Posts: 969
Location: Utah
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| Posted: Thu Dec 31, 2020 3:53 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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| richardcraineum wrote: |
dont believe everything you read on the internet they say, and i dont believe that one at all.
i had a 1600 with an old rayjay turbo kit ( same one thats on my 2276 now) and it wouldnt START to spool until 4500 rpm and wasnt full on until 5000 to 5500 rpm. i had to shift that poor stock bastard at 6000 rpm just to enjoy any boost at all. ( well, by any i guess i mean 20lbs heh heh ) but 20 doesnt really take much longer to reach than 10...
same set up on a 2276 and im in the thick of it by 3000rpm.
maybe ol boy put an hx35 on a 1600, but it aint no "1600". is he slinging that thing to 10k? high c.r. to move more cfm and spool the turbo? nitrous? i dunno, but i smell something funky in that kitchen |
There are a few guys on the other side of the world doing similar. The same guy referenced here just went 9.4 at 145mph or something close to that with a 1585, big turbo, huge boost, stock valve size heads. He took that 1641 into the 8s in the 1/4 in 2018 or 2019. Rpm is a big factor, they also launch on a two step to get the turbo spooling. I'm sure that they are laggy pigs if just driving around. |
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buguy
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Joined: November 17, 2003
Posts: 4915
Location: Port Orange, FL
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| Posted: Thu Dec 31, 2020 5:06 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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Agreed. And the OP stated that he was building for drag race. I believe i read they were launching at 7500 rpm or something there abouts.
Also in that link there are some videos i believe. Nitrous would be a great idea to get some good spool though!
Also even though the HX35 is a physically large turbo i don't think it's really that "big". Remember they were designed for a diesel truck that probably maxed out at 3000 rpm. Certainly wouldn't be a low end grunter though! |
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clonebug
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Location: NW Washington
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| Posted: Thu Dec 31, 2020 10:10 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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If I remember correctly the Holset H1C, HX30, HY35 turbo family are capable of supporting around 500 hp.
Those Swede's were making around 390 to the wheels and more.... at 8000 rpm using a stock crank and stock but ported heads.
There are videos on the internet that back them up if you want to look.
I've been drooling over their accomplishments for a few years.
They have since moved on to bigger and better turbos and are still putting down some amazing times.
While I would love to have that power it's just not practical and I'll be happy with my 220 crank hp and 258 ft lbs. torque and be able to drive it anywhere.
For me reliability is the key along with power.
For the OP I feel it is better to pick a hp goal and size the turbo to meet that.....
In order to make max power you need the rpm's...that means you also need to give it the flow potential to make that targeted hp.
More high rpm power means you give up some bottom end....for a race car you don't need bottom end if you can keep the rpm's up.
8000 rpm doesn't work for me on the street........
_________________
| vwracerdave wrote: |
Take a good long look in the mirror and report back on what you see. |
| Paul.H wrote: |
| That one line on that chart is probably better info than you can get from this place in a month |
My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash
http://www.shoptalkforums.com/viewtopic.php?f=3&t=127936 |
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BFB
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Joined: November 03, 2014
Posts: 1751
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| Posted: Sat Jan 02, 2021 11:27 am Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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https://www.dsmtuners.com/threads/how-to-read-the-hx35-hx40-compressor-map-s.362599/
heres a link to the best maps i could find without spending half the day searching.
on the low end these turbos ( apparently there are a few sizes and blade designs ) will flow 54 lbs at 3.0 pressure ratio in the 75% + efficiency category. which i believe is around 30psi @ 600cfm, and you could push it further youd just be outside of that efficiency range.
i know there are bigger better just like everything else in life, but to find an equivalent " junkyard" turbo for the the price of these i think youd be hard pressed.
according to the " not2fast" turbo calculator for a 1600 cc engine to use 600 cfm at 30 lbs of boost itd have to be turning 12,000 rpm!
i think one of us should build this just for shits n grins..
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1 |
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Stripped66
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Joined: May 31, 2005
Posts: 3469
Location: Charleston, SC
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| Posted: Sat Jan 02, 2021 4:33 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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| richardcraineum wrote: |
heres a link to the best maps i could find without spending half the day searching.
on the low end these turbos ( apparently there are a few sizes and blade designs ) will flow 54 lbs at 3.0 pressure ratio in the 75% + efficiency category. |
That's off the map, even on an HX40.
From that same thread, an HX35 map that has been converted to lbs/min:
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| 66brm wrote: |
| Bodacious wrote: |
| Why not just make a custom set of wires with a Y splice in them. Then you could just run one distributor. |
I don't think electrickery works that way |
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buguy
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Joined: November 17, 2003
Posts: 4915
Location: Port Orange, FL
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| Posted: Sat Jan 02, 2021 6:54 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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| A 1641 with 25 psi of boost makes 300 hp at 7000 rpm. That would need 33 lbs/min to make that. |
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BFB
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Joined: November 03, 2014
Posts: 1751
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| Posted: Sat Jan 02, 2021 8:02 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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| Stripped66 wrote: |
| richardcraineum wrote: |
heres a link to the best maps i could find without spending half the day searching.
on the low end these turbos ( apparently there are a few sizes and blade designs ) will flow 54 lbs at 3.0 pressure ratio in the 75% + efficiency category. |
That's off the map, even on an HX40.
From that same thread, an HX35 map that has been converted to lbs/min:
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i went back and looked again and didnt see that map you posted, looks to me like you picked a map that someone " converted" as it says at the top instead of any other maps which were all close to the same , just to prove your point.
did you happen to actually read the map you posted and notice that its converted to 13.94 psi, and not atmospheric pressure of 14.7? golly gee, that might explain why its lbs/ min are lower than the other maps....
i didnt see you trying to do any research or calculations and i do, and u wanna just pick one map to tell me im way off? thats a dick move.
but whatever i think some of you ppl are just here to argue about shit
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1 |
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| Back to top |
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BFB
Samba Member
Joined: November 03, 2014
Posts: 1751
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| Posted: Sat Jan 02, 2021 8:11 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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| buguy wrote: |
| A 1641 with 25 psi of boost makes 300 hp at 7000 rpm. That would need 33 lbs/min to make that. |
buguy, heres a screenshot what not2fast comes up with for that. i know theres a lot of online calculators and sure there is some inaccuracies between them, but this is the one i like best so far. what do you use?
maybe i left out or need to change a category?
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1 |
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| Back to top |
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Stripped66
Samba Member
Joined: May 31, 2005
Posts: 3469
Location: Charleston, SC
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| Posted: Sat Jan 02, 2021 9:24 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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| richardcraineum wrote: |
i went back and looked again and didnt see that map you posted, looks to me like you picked a map that someone " converted" as it says at the top instead of any other maps which were all close to the same , just to prove your point.
did you happen to actually read the map you posted and notice that its converted to 13.94 psi, and not atmospheric pressure of 14.7? golly gee, that might explain why its lbs/ min are lower than the other maps....
i didnt see you trying to do any research or calculations and i do, and u wanna just pick one map to tell me im way off? thats a dick move.
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First of all, I used the resource you cited for these Holset maps: https://www.dsmtuners.com/threads/how-to-read-the-hx35-hx40-compressor-map-s.362599/ It's in the first post of that thread: "Another 8blade hx35 compressor map: Unofficial, but detailed."
Second, look at the HX30 and HX40 compressor maps; it has Holset's obscure mass flow on the bottom x-axis, (kg/sec)*√K/mPa, and the standard lb/min on the upper x-axis. These have a basic, linear relationship. Your calculation of 54lb/min is approximately 72 (kg/sec)*√K/mPa.
Third, if you look at the 'official' Holset HX35 map, you could liberally estimate that the 75% efficiency island would land somewhere around 60 (kg/sec)*√K/mPa. Going back to the HX30 and HX40 maps, which depict both volumetric scales, 60 (kg/sec)*√K/mPa = 45 lb/min...NOT 54 lb/min.
Finally, that 5% difference in the reference pressure (actually, 3.4% difference, using Holset's reference pressure of 14.425 psi...but who's reading the maps  ) whoever used to convert that HX35 map (which -AGAIN- was posted in the thread THAT YOU REFERENCED) doesn't change the fact that your calculation was off by 20%. It wasn't one, cherry-picked map. Overlay your 54 lb/min estimate on all of the Holset maps and your math doesn't compute.
| richardcraineum wrote: |
but whatever i think some of you ppl are just here to argue about shit |
No, some of us are trying to have a discussion. Facts don't give a d@mn about your feelings. Either get it right, or learn something and grow up.
_________________
| 66brm wrote: |
| Bodacious wrote: |
| Why not just make a custom set of wires with a Y splice in them. Then you could just run one distributor. |
I don't think electrickery works that way |
Last edited by Stripped66 on Sat Jan 02, 2021 9:28 pm; edited 1 time in total |
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clonebug
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Joined: January 29, 2005
Posts: 4027
Location: NW Washington
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| Posted: Sat Jan 02, 2021 9:25 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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| richardcraineum wrote: |
| buguy wrote: |
| A 1641 with 25 psi of boost makes 300 hp at 7000 rpm. That would need 33 lbs/min to make that. |
buguy, heres a screenshot what not2fast comes up with for that. i know theres a lot of online calculators and sure there is some inaccuracies between them, but this is the one i like best so far. what do you use?
maybe i left out or need to change a category?
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Not sure why you're are using a 60* C. as an IAT........you'd be nuts to have it that high when trying to make that kind of power. Also 13.3 afr is detonation time with IAT's that hot.
AFR's should be 12.0:1 or even 11.5:1 for safety.
I run 25 lbs boost with WI and a small intercooler and see boosted IAT's of 87-95* F.
_________________
| vwracerdave wrote: |
Take a good long look in the mirror and report back on what you see. |
| Paul.H wrote: |
| That one line on that chart is probably better info than you can get from this place in a month |
My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash
http://www.shoptalkforums.com/viewtopic.php?f=3&t=127936 |
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buguy
Samba Member
Joined: November 17, 2003
Posts: 4915
Location: Port Orange, FL
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| Posted: Sat Jan 02, 2021 11:07 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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Agreed with clone. Intercooler efficiency should be in the mid 90's and volumetric efficiency should be mid 80's (that will rise with rpm too).
However i do see higher iat's than clone. Mine averages maybe around 110f-120f and i have seen spikes to 160. I think my ambient temps are higher than his iat. |
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clonebug
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Joined: January 29, 2005
Posts: 4027
Location: NW Washington
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| Posted: Sat Jan 02, 2021 11:36 pm Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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| buguy wrote: |
Agreed with clone. Intercooler efficiency should be in the mid 90's and volumetric efficiency should be mid 80's (that will rise with rpm too).
However i do see higher iat's than clone. Mine averages maybe around 110f-120f and i have seen spikes to 160. I think my ambient temps are higher than his iat. |
I'm not sure what intercoolers usually rate at but keeping IAT's as close to ambient as possible is a good thing.
That's why I use both......W/I worked fine until I went above 21 lbs. boost especially in the summer months.
Once ambients get around 70-80* F it gets harder to keep the boosted temps down.
I have found anything over 130* F is not good.
_________________
| vwracerdave wrote: |
Take a good long look in the mirror and report back on what you see. |
| Paul.H wrote: |
| That one line on that chart is probably better info than you can get from this place in a month |
My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash
http://www.shoptalkforums.com/viewtopic.php?f=3&t=127936 |
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buguy
Samba Member
Joined: November 17, 2003
Posts: 4915
Location: Port Orange, FL
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| Posted: Sun Jan 03, 2021 7:59 am Post subject: Re: 1835ccm Holset Turbo - A/R .82 too much? |
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I don't disagree with that. I think the E85 saves my ass there. I was seeing 120 with regular gas too, but i had it limited to 12 psi and was running 7.8:1 compression at that time. W/I seems to cool better than an intercooler.
Intercooler effectiveness appears to start around 99% and ramp down to around 90% at redline.
Clone, my ambient temps are usually higher than your boosted temps. |
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