Not long ago I acquired a turbo ap1. The prior owner spun 3 bearings on the original motor and purchased a FRM built long block from Christian over at inlinePro. The specs are as follows: (copy & pasted from Christian’s reply email after reaching out to him for verification on build)

[Yes, I sold Tyler the motor a few months ago. I cant imagine that motor having more than 1000 miles on it. The Motor is a FRM built motor: Mahle Pistons 10:1, InlinePRO Rods with 3/8 bolts, Acl Bearing set. Cylinder head: Supertech Springs & Retainers, Supertech valves, guides, Stock cams, ARP head and mains.]

Ok cool, so it checks out with what he said....now, this motor has a pte 6266 dbb, id1000, sheepy ff vband manifold, garret ic, fender exit exhaust etc. It seems like a nice build but I have several concerns.

- Christian stated the Mahle pistons are 10:1 stock bore (87mm). I did some searching and Mahle apparently makes 10:1 cr piston for the F22C, not the f20c. Can someone confirm if they’ve since made 10:1 cr pistons in standard bore for the ap1?
i don’t understand why the previous owner didn’t just sleeve the block and ran aftermarket pistons. I’m looking for longevity, I’m also not searching for big power although I’d be content at 600 on 93. The motor runs fine, no issues and is not tuned yet (finished breaking her in). I’ve driven about 300 miles so far and the previous owner put about 400.

-I’ve read issues particularly in a h22 (FRM sleeves with Mahle compatible piston) where a tuner found scarring on the sleeves after inspecting the motor that destroyed itself while tuning it. Could be a bad hone job but the owner of this h22 didn’t know if it was honed at all. Some say it’s not needed and these are crucial information that I have no idea whether it was performed or not on this s2k.

why is frm better than sleeving? I would think a sleeved block is a lot more stout than an open deck design, even more for a turbo build.

even after aftermarket darton iron sleeves it will still be an open deck design in most cases. 600whp is a pretty crazy high goal for any 4 cylinder engine on straight 91/93 octane pump fuel.
The stock frm engine with stock rods and pistons are known to hold 600+whp with no issue. I run a 100% stock block with about 600whp and it has 135k miles and it’s been boosted since about 60k miles.

you have a new inline pro built engine. Just hurry up and get the car tuned.
And you should be fine. I would make sure you have a fuel fuel sensor and get a flex fuel tune.

is your f20/22c internals completely stock? If you don’t mind me asking, what kind of power did you make on pump? And you’ve been turbo for more than half your car’s mileage! Any rebuilds or tear-downs?

yes my f20c has a stock block and no it has never been rebuilt in its 135,000 miles life. My current turbo setup dynoed at 425whp on 91 octane and 588whp on e85. But I use to have a bigger turbo on my old setup which make 450whp on 91octane and 640whp on e85. Like I said 600whp on straight low octane 91/93 octane pump fuel is not realistic on a 4 cylinder engine.

agree, these engines are high compression so boost will be on the lower end. My evo when it was stock motor did 577 on pump at 34 pounds, but then again the 4g63 has a 8:8 cr so it does 30 psi of boost all day like nothing

Get it tuned, let her eat.

I understand your concern, but you have to look at it in IPs shoes to. You think they would be slappin these longblocks together, putting there name on it, if it wasnt up to some kind of par? IP is pretty high on the list of names for the 4cyl “builder” list; speaking s2k F’s.