
Compression Ratio For 200+ Bhp
#1
Posted 18 February 2023 - 06:37 PM
10 years ago I did the same on my mini, using a genuine 1275 metro turbo block and pistons. I was running 14psi of boost and was a good laugh, it had a modified head, cam, brand new T3. I never had it on the rolling road but from others running a similar spec I guessed it was around the 140bhp mark. Didn't know what the compression ratio was on it.. a bit silly I know.
My question is what compression ratio should I am for, I know that a too low compression ratio will cause it to a bit of a dog off boost, but I don't really mind that, (to a certain extent) I was thinking around 8.1:1 C/R and running around 18/20psi. I have seen others running even lower and obviously gaining more power.
Also what spec cylinder head would you go for regarding what size valves.
So the spec I am going for with this build is-
A+ 1293cc
Reconditioned T3 turbo
(Cylinder head undecided on spec)
+20 Forged omega 18cc Pistons
Ph2 turbo cam
Aldon turbo dizzy
big front mount intercooler
Swiftune alloy/alloy duplex
2" maniflow exhaust system
ARP con rod bolts
ARP 11 head stud kit
Final drive 3.6:1
Thanks.
#2
Posted 18 February 2023 - 08:56 PM
200 bhp? For how long …
#3
Posted 19 February 2023 - 08:24 AM
200 bhp? For how long …
Loads of A series turbo engines are 200bhp+ now. Just need to make sure its fuelled and cooled correctly.
#4
Posted 19 February 2023 - 10:19 AM
#5
Posted 19 February 2023 - 01:54 PM
#6
Posted 19 February 2023 - 03:22 PM
Going for that power I'd think you'd want to ditch the dizzy for a 3d mappable ignition system and a more modern turbo than a T3 like 1752 will make that power more efficiently. Managing heat and ignition properly will allow a higher CR. I'd think you'd need some gearbox mods to run that power and an RTS clutch.
It's going in a Marina van , so the cooling won't be a problem, RTS clutch isn't relevant and the gearbox will be the best bit of the build, I agree about the mappable ignition though, it'll be well worth it.
1 user(s) are reading this topic
0 members, 1 guests, 0 anonymous users