B25/B27 turbo set up ideas

[Andy348]

I've got an M20B25 blowing some oil and an M20B27 block with pistons (1986, not SETA) that I was thinking about building up for a turbo build. I am looking for 300ish bhp, nothing insane, but it needs to be reliable. Looking for a car to drive cross-country that I don't need to fiddle with on the daily. If this doesn't seem plausible I'll just do an S50 swap.

I've done some research and understand that reliability is in the tuning. My ideas thus far are:

kamotors turbo kit (ARPs, MS pnp, etc)
BimmerHead rebuilt B25 head on the B27 block w/turbo cam
I've already got a stage 2 clutch kit
Just got a 2.5" single exhaust built for my M20 that I would love to keep
Rebuilt bottom end?
LC1, other gauges necessary

Couple of questions. First off, how far am I going with the bottom end rebuild? I don't know much about the block, just no cross hatching left I believe. If I'm looking for reliaiblity with some budget-oriented aspect, I'm assuming rings, bearings, honing? I know its impossible to tell without really looking at it but I'm just trying to get an estimate on bottom end rebuild costs so I can factor that into the potential budget.

2.5" exhaust - most recommend 3", but this one is so beautiful I'd really like to keep it. Free flow, no cat. Will I be able to make 300ish with it?

Bimmerhead - welded water jackets or no? My guess is not necessary, but worthwhile if I've got bigger plans down the road. And I'm assuming those bigger plans will not withstand 2.5" exhaust :(

In terms of the actual build I've already got Corky Bell's book and Maximum Boost that I've read once but both will need another go-over. If someone can recommend a book/extensive specific thread on the basics of MS tuning I'll love you forever ;D

Back to researching!

[jaywood]

Reliable 300hp can be done easily. See -ak for example. Or kamotors. Proven and reliable setups that can be DD'd.

Exhaust - you're going to hear mixed opinions on whether or not the 3" is necessary. Personally I was in the same situation as you are (2.5" was preferred due to ground clearance) but ended up going 3" just in case I wanted more HP. I'm glad I did

There are lots of guys who have made 300 + HP on the stock head so I wouldn't worry about dropping sub $1k on a new head unless you have a huge budget.

Youtube is a good source to learn about tuning and MS and tunerstudio.

PS, I'd recommend the AEM UEGO over the LC-1. Installation is much easier and no calibration needed.

Good luck man!

[TheTacoMan]

300hp is very easily dd friendly. Its all in the tuning.
A head isnt necessary but it will help getting there at a lower boost.

[Andy348]

Jaywood - thanks for the recommendations. Just sucks that I spent $700 on an exhaust that will be useless to me! :( I will check out youtube for MS tuning + google AEM wideband
Taco - I figured as much about the head. I need reliability but I have no access to a dyno. I can do my very best to learn to tune on the street (I have wide open roads) but I need to be sure I can make it reliable.

Some more questions:
SETA pistons - smart/necessary for E block and I head? I think it'll net me a bit more compression over the ETA pistons, not sure if thats necessary or smart.
HP/$ - lets say I really went all out and wanted 400whp. What changes? From what I've read it would be tune (of course), exhaust (definitely 3"), and potentially injectors?
Head - if I don't buy the BimmerHead, what should I recondition on mine? Rockers I assume, valve seats, springs, maybe valves if they're leaking?

I want to do it well in one shot. Nando recommended to me at one point to learn to tune on my M20B25 so if I mess up I won't be ruining my newly built engine. I think that's a great idea. If I can get the MS up and running and learn to tune immediately, it shouldn't be a huge set back once I've got the turbo system all hooked up.

I need reliability though. I've spent an entire summer working on the car, and I don't really want to do the same thing again. I know problems show up, but reading Kamotors build thread again got me scared - pages and pages of small little problems that are more of an annoyance than anything, but truly affect driveability. I don't want something that I will need to tinker with every time I want to drive it