2.1 or 2.5 engine
09 October 2018 | 01:23 PM
#1
2.1 or 2.5 engine
Probably been asked before but hey ho.
So im looking at uprating the engine in my impreza sti widetrack and iv seen a few engine options, 2.0, 2.1, 2.35, 2.5, theres probably more but the main ones iv seen.
Iv seen a couple of engines for sale a 2.1 which is built to a good spec and a 2.5 again built to a good spec.
The 2.5 is alot more ££ than the 2.1.
My aim is to get a quick road car and maybe the odd track day in the future and looking for around 480-500bhp
So which would be better the 2.1 or the 2.5?
thanks
So im looking at uprating the engine in my impreza sti widetrack and iv seen a few engine options, 2.0, 2.1, 2.35, 2.5, theres probably more but the main ones iv seen.
Iv seen a couple of engines for sale a 2.1 which is built to a good spec and a 2.5 again built to a good spec.
The 2.5 is alot more ££ than the 2.1.
My aim is to get a quick road car and maybe the odd track day in the future and looking for around 480-500bhp
So which would be better the 2.1 or the 2.5?
thanks
09 October 2018 | 03:13 PM
#2
Scooby Regular
Joined: May 2018
Posts: 387
Likes: 2
From: Newtownards - Northern Ireland
The best thing to do would be list the relevant spec and prices of the engine options you are looking at. Parts used will be a big factor on reliability etc.
the 2.5 will have more torque over the 2.1
the 2.5 will have more torque over the 2.1
09 October 2018 | 08:08 PM
#6
A 2.1 cdb has gotta be the reliable one with quality parts of course, 2.5 cd inserts are reliable upto a certain bhp because of thin liners, a 2.35 using a 22t block is great and a in between of both but at a great cost also but the best choice for big power builds.
take your pick in what you want, any 3 will be fine at your level but needs to be a good build with good parts for reliability
take your pick in what you want, any 3 will be fine at your level but needs to be a good build with good parts for reliability
10 October 2018 | 12:32 AM
#7
This any good, it’s a 2.1?
Ej20 semi closed deck block
Group n arrow billet crankshaft
Group n arrow Conrod’s
ACL race bearings
Omega group n pistons
RCM 14mm head stud conversion
Spec c big port heads with oem spec c cams
Uprated valves and spings
RCM 12mm modified oil pump
Group n Twinscroll baffled sump
Ej20 semi closed deck block
Group n arrow billet crankshaft
Group n arrow Conrod’s
ACL race bearings
Omega group n pistons
RCM 14mm head stud conversion
Spec c big port heads with oem spec c cams
Uprated valves and spings
RCM 12mm modified oil pump
Group n Twinscroll baffled sump
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10 October 2018 | 07:18 PM
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10 October 2018 | 11:06 PM
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11 October 2018 | 12:35 AM
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11 October 2018 | 07:49 PM
#15
p.s I'd want proof of that billet crank as that's a lot of pee. And pics of build from seller?
14 October 2018 | 08:43 AM
#16
Scooby Regular
iTrader: (4)
Joined: Nov 2004
Posts: 765
Likes: 0
From: where there are no gatsos and no speed limits
if built propperly , a 2,5 will be better on every aspect. it will have better torque and earlier spool. that spec you have given for the 2.1 is over kill regarding the crank and the oil pump. both the crank and the oil pump would be a good investment if you want to achive 700+bhp at some point but want to hang around at 450bhp mark for a while. but then you wouldn't take a semi cd as your base (scd runs out of breath after 550ish bhp). also there is the 14mm stud issue for me. i dont have experience building a big hp 2 liter so not sure about clearances but on a 2.5 semi cd it would be a big no no for me to put 14mm studs as they touch the liners and thin the liners down. if when they drill bigger holes (for the 14mm studs) on a 2 liter block and touch the liners you could easily crack a cylinder wall. i beleive the arrow crank, 12mm rcm oil pump and the 14mm studs belong to a cdb or even a sleeved block aiming for at least 700+ bhp. you dont put an arrow crank in your engine for 450 bhp. it is like giving a gold plated barbie doll to your 3 year old.
14 October 2018 | 10:04 AM
#17
if built propperly , a 2,5 will be better on every aspect. it will have better torque and earlier spool. that spec you have given for the 2.1 is over kill regarding the crank and the oil pump. both the crank and the oil pump would be a good investment if you want to achive 700+bhp at some point but want to hang around at 450bhp mark for a while. but then you wouldn't take a semi cd as your base (scd runs out of breath after 550ish bhp). also there is the 14mm stud issue for me. i dont have experience building a big hp 2 liter so not sure about clearances but on a 2.5 semi cd it would be a big no no for me to put 14mm studs as they touch the liners and thin the liners down. if when they drill bigger holes (for the 14mm studs) on a 2 liter block and touch the liners you could easily crack a cylinder wall. i beleive the arrow crank, 12mm rcm oil pump and the 14mm studs belong to a cdb or even a sleeved block aiming for at least 700+ bhp. you dont put an arrow crank in your engine for 450 bhp. it is like giving a gold plated barbie doll to your 3 year old.
14 October 2018 | 06:07 PM
#18
I'm with k duraman 100% there, apart from the 2.5 better in every aspect (not as good as a 2.1 cdb on track when at extreme temps the 2.5 liners will be weaker and could crack etc)
amd yes 11 extreme are fine for most applications, shrek, most say 14 as it's probably sounds safer for the customer lol. What folk tell you take with a pinch of salt and figure the wider picture out yourself and go from there on what's suitable and what's not.
amd yes 11 extreme are fine for most applications, shrek, most say 14 as it's probably sounds safer for the customer lol. What folk tell you take with a pinch of salt and figure the wider picture out yourself and go from there on what's suitable and what's not.
Last edited by bustaMOVEs; 14 October 2018 at 06:08 PM.
14 October 2018 | 07:50 PM
#19
I'm with k duraman 100% there, apart from the 2.5 better in every aspect (not as good as a 2.1 cdb on track when at extreme temps the 2.5 liners will be weaker and could crack etc)
amd yes 11 extreme are fine for most applications, shrek, most say 14 as it's probably sounds safer for the customer lol. What folk tell you take with a pinch of salt and figure the wider picture out yourself and go from there on what's suitable and what's not.
amd yes 11 extreme are fine for most applications, shrek, most say 14 as it's probably sounds safer for the customer lol. What folk tell you take with a pinch of salt and figure the wider picture out yourself and go from there on what's suitable and what's not.
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