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A month ago I got home from school (thanks corona) and started screwing around with my Mazdaspeed. I have had a somewhat random and sudden power drop under load for a while now (felt like a misfire), so I did some datalogging with the Hydra to diagnose the issue... and I broke the car. A quite loud tick started after the second pull and I think I bent a rod.
Kinda sucks but now I have an excuse to do what I have wanted to do for a while: make the engine and turbo bullet proof so I can drive and occasionally track the car with confidence. As such, I am aiming for 250-275 whp around town and 225 whp on track with the rev limiter set to 7200rpm. 225 whp is right around where the car was before I broke it and will be plenty for me around the track (for now atleast).
So here's the part list: Engine
Supertech 84mm 8.6:1 Pistons with Winesco Rings
Manley H-Beam Rods
ARP Head and Main studs
ACL Race bearings
Boundary Engineering 2 shim oil pump
Fluidamper Damper
OEM 98-00 Head Gasket
Supertech Heavy Double Spring Kit
Supertech Intake and Exhaust Valves
OEM valve stem seals Turbo
BorgWarner EFR 6258
Kraken Cast Manifold and downpipe
Oil and water hardlines
Inconel hardware While I am in there
LS coils
New clutch and pressure plate
Timing belt and general maintenance (new gaskets, seals, etc.) Things I already have
Intercooler and piping (that will need rerouted)
Hydra 2.7
Walbro 255 fuel pump
550 RC injectors
QMax Coolant Reroute
A big aluminum radiator
FM 2.5" exhaust Things I could be convinced to get/do
MS3PnP
Port the head
Larger fuel injectors
As a mechanical engineer in training who wants to someday work in motorsports, this should make a good learning experience and I hope to have some fun in the process. The goal of this thread is to document that process and consult the great collective wisdom of this forum. So, if you have concerns about any of my methods, ideas, or decisions, please let me know below. Thanks for reading
First things first: pull the engine. Labeling stuff was tedious but very necessary as I am not the one who messed with the wiring when the Big Enchilada was installed years ago. The lift made things easy and she was out in no time.
Tranny came off next and the clutch actually looks pretty good to my untrained eyes. I am inclined to replace it while I have it apart but I could be convinced not to.
First person to correctly guess what the other engine is in the background gets a pos cat.
Nice list of part$$$$$$. but holy overkill batman.
I would not touch the head, unless theres something wrong with it.
Not worth it for a ~300hp build.
im running a 6258 on kraken hardware, on 94 block/stock 94 pistons with a 200k mile untouched vvt head, making 250hp on medium wastegate spring pressure (9-11psi) track mode and 309hp at 17psi street kill mode.
done autox, track, drag without issues.
like said above, look into Flowforce 640cc injectors, they are good for about 320hp pump gas. or get 960cc for more head room or e85.
nb2 coils are fine for ~300hp, not a must to have ls coils.
Noted. I may move the money I budgeted for the head to the MS3. My concern would be that swapping ecus would result in wiring issues but if they are both PnP I guess there would be no problems. I'll have to do some more research first.
Flowforce 640s definitely in the budget now.
Carnage pics for your viewing pleasure. The ticking noise was piston number 3 contacting the crank at the bottom of the stroke. Some of the oil squirters were bent as well. I think what was causing the stuttering before the car broke fully was the ecu detecting knock from the pistons just barely contacting either the oil squirters or the crank and then moving to an emergency fuel and timing map until the knock receded.
Crank and cylinder walls look good. The big end bearing journal pictured had the worst mark but it is smooth to the touch. My only concern is damage done to the crank from it hitting the piston skirt.
Crank and cylinder walls look good. The big end bearing journal pictured had the worst mark but it is smooth to the touch. My only concern is damage done to the crank from it hitting the piston skirt.
Was there significant damage to the skirt of the piston? Are there marks on the crank?
The crank is forged steel, while the piston is cast aluminum. IMO if you have incidental contact then you are fine. Can u post better pictures showing the damage?
Was there significant damage to the skirt of the piston? Are there marks on the crank?
The crank is forged steel, while the piston is cast aluminum. IMO if you have incidental contact then you are fine. Can u post better pictures showing the damage?
There are no visible marks on the piston skirts but they could be slightly bent and I would not be able to tell. Could that be a mark on the crank? That would be the point of contact as the number three rod was the most bent. Going to the machinist tomorrow so we'll see what he says but seems to me that it is ok. There were a few small shards of something stuck in the oil pick up tube screen but no metal in the oil otherwise.
A quick update. I took the block to a machine shop a friend recommended and only to find out a week later that he doesn't have small enough tooling to align hone/bore a BP4W or to bore the cylinders. Wish he told me he would not be able to do when I said it was a 1.8L.
I also need to source a new EFR 6258 so if anyone has any suggestions on the best place to do that let me know. Cheapest I found was at turbokits.com.
Ok did a bit more digging and TCS has the whole turbo here for $1325.41. Probably going to go with that because I just read some good reviews. Thanks guys.
So the machine shop mic'd the cylinders and they are nearly dead straight and wouldn't require more than a light hone. Machinist said it would be a bit of a shame to go 0.020" for the Supertech pistons and I kind of agree with him. CP 9:1 is the only off the shelf billet or forged aftermarket piston I could find in the stock bore with a reasonable CR but they are 2618 alloy which I would really rather avoid. I should probably just go with the Supertechs but man am I torn.
Stock pistons will work fine for the power goals you have listed. If you are really holding yourself to those goals, and your stock pistons are in good shape, then why change?
Trying to fit new pistons into old bores is usually an exercise in futility.
Forged pistons always require larger bores than cast so the bores will have to be increased .001-.004"
Sometimes this can be accomplished by honing alone but this is not as accurate as boring and then honing.
Only time I re-use the original bore I am also reusing the original pistons and I keep them in their respective bores.
The 2618 alloy requires looser clearances and thus a bigger bore.
I would go Supertech in the first oversize or (if I was cheap shitting it) reuse the original pistons. The original pistons should work ok to 300HP and maybe more.
The original pistons will NOT have oil consumption issues if the honing and ring fitting is done correctly.
I've also never seen a used bore that I was completely happy with. They almost always have some "out of round" or taper issues that I can seen on the bore gauge.
Most of the time they work ok but if I'm being serious (and you are) boring is the way to go in my book.
Your original parts list is way overkill unless your shooting for 400+
Folks here have achieved 400+hp on stock heads.
One thing you original list is missing is a intake manifold change.
Go with a flat top or 99-00 VICS.
The stock MSM manifold sucks...
If you are really holding yourself to those goals, and your stock pistons are in good shape, then why change?
Stock MSM CR is 9.5:1 so mainly detonation concerns in case anything were to go wrong. Of course, I could get cast 9:1 but why spend the money on new cast when I could just go forged and not have to worry about it as much. I'm just going to bite the bullet and bore for the 83.5mm Supertechs. No sense in messing with a proven formula.
The stock MSM manifold sucks...
It does suck and I will eventually go with the flat top. Might buy it from PrestigeSparesUK if one doesn't pop up stateside.
6758 is 100$ cheaper there
A little to big for what I want to do I think. Also, the reason I chose the 6258 was for the fastest spool around.
04-20-2020, 02:33 AM
College Student Attempts Full Rebuild
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Wish he told me he would not be able to do when I said it was a 1.8L.
