Good morning from France,
After 2 years of trackdays with my e30 N/A I would like to turbo it.
What I have in mind is buy an other M10B18 from a 318i e30 and prepare it this winter with just a new headgasket.
I also bought a 2l crank but for an upgrade maybe the next winter.
So, I would like to have around 230Hp with the B18. But most of all I want it to spool very soon to not have a "ON/OFF" turbo. The pressure will be less than 12psi.
I will go with a rapidspool manifold with an external WG (to keep it for the next setup)
What do you think about the Garrett GT2860R or the GTX2860RS GEN2 (to keep it for the next setup) ? With a T3 A/R .48 or a TIAL A/R .52 V-band.
I read a lot of post on the subject but I don't understand something:
For the M10B18 with a VE% of 80, at 2500rpm it will take 4,6lbs/min. <br>So on the compressor map I put a point at 4,6lbs/min on 1 pressure ration axis:
After, at 3500rpm and 12psi of boost it will take 10,5 lbs/min:
And after keeping the boost at 12psi to the redline 6500rpm where the engine will take 20lbs/min:
What I don't understand is, how can we know that it will spool straight from 0 psi to 12psi at 3500rpm, the exhaust side is important for that right?
If maybe at 3500rpm it will do 0boost and my arrow from 2500rpm to 3500rpm is unpossible.
Hope i'm clear enough!
Thanks a lot for your help
Arthur
Last edited by Arthuring; 10-07-2018 at 12:27 PM.
Find some dyno examples of similar size motors with the turbo you want, such as a Mazda Miata. If I were trying to do what you want I would get a used turbo from a Subaru wrx or something like that.
A Borg Warner EFR 6258 is a far superior turbo to either of the ones you mentioned, and you don't need anything else to make it work (BOV and internal wastegate keep it all contained). The 1.8L Miata guys love it. It'll do a little over 400 rwhp max'd out.
Don't worry about plotting out compressor maps perfectly, as there's way too much stuff going on to draw straight lines anywhere. It just gives you an idea of the power potential of a compressor, but the whole package matters.
Thanks a lot, this look like a very good alternative indeed!
What do you think about a T25 A/R .64 for ta 1L8 and 2l M10?
Holset HE221W could also work pretty good. But has internal wastegate..
The T25 turbine will support the power just fine for either engine - BUT - it uses M8 turbine housing to turbo manifold studs/nuts to hold it on. If you actually drive your car hard, these will be under tremendous stress, and they'll usually yield at temperature and stop holding the turbine tight to the housing.
The 0.80 A/R T4 twin scroll IWG housing is better IMO. It will offer a very comparable boost threshold due to the twin scroll design, and it will flow better in boost. It also uses M10 turbine housing to manifold hardware, so you don't have to go to quite as exotic of materials to get things to hold together there.
Thanks for your help.
I guess I need a twinscroll manifold to fit the twinscroll exhaust housing?
Yes, with the correct flange size (T4 is much larger than T25 etc.).
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