New to the forum, I went full stupid...

Hey folks,

Leif here from Ontario, Canada. I've had my 2008.5 Mazdaspeed 3 since 2012 I think, and just recently started a forged engine build. Looking to do time attack, and am building towards that goal. Engine is currently torn apart at the builders shop, and the block is recently back from the machine shop. Hopefully reassembly starts next week.

Plan is to run somewhere in the 320 whp range so that I'm not running at engine peak HP/TQ. I've been doing some online training from HP Academy for flash tuning, but I'll be starting with a professional dyno tune.

I've done a fair amount of work myself, learning as I went. Suspension I've done a couple times, and just recently installed a new Bilstein B12 Pro-Kit suspension. Prior to the build, I was mildly upgraded with a CP-e TMIC, HPFP, Cobb AP, EGR block off and delete, blah blah. Typical stuff. Car is super fun.

As the car is no longer a daily, and the fact the MS3 market is kind of shit for re-sell right now, I've decided to just build this car out for track use. Not doing anything so far as stripping it right now, but depending how the summer goes, track experience, etc we'll see about that.

The idea is to build a forged engine (K1 rods, Wiseco pistons, stock compression ratio), and do the majority of the track prep to keep the engine as close to reliable as possible. Going to use a Garrett GTX2867R for the turbo, JBR 3" intake, and Ultimate Racing downpipe + resonated testpipe. Also going to add powersteering and oil intercooler. I'll maintain the CP-e TMIC.

That's basically the high level overview. Once the build is complete and things are tuned, I'll be starting towards tuning the suspension. I've done a fair amount of reading about suspension profiling, and I want to map it all out, adjust to a baseline, and see where that gets me before I start adjusting too much there. I've read the great thread by phate1985 about harmonics and such. I need to find out what the spring rates are of the B12 Pro-Kit, do a corner weight measurement, and start plugging things into a spreadsheet.

I think that's enough about my car...

 

Welcome, I would go 3.5" intake as the colder candian weather you might overflow your maf with a 3" intake. Why not go with a 3076 if you are going built? You will get really good spool and power but not insane. You will want to look into Port Injection as well if you are going to try to get reliable power over 375whp which is only really achievable on stock fuel with an e30 tune. Talk to @VTMongoose about suspension.

 

I have modest goals, and I believe the GTX2867 is the better fit than a larger turbo. I don't plan to run high WHP (right around 320whp for my class). It'll have faster spool, and looks to be more than capable of achieving the peak HP I'm looking for. I also won't be running in the winter (this is a summer track car now), so I'm not worried about overflowing the MAF, especially with the lower HP setup I'll be running.

I'll never need port injection, and plan to just run pump gas (or maybe race fuel next summer when I start towing). I know. I'm building an MS3 and not running peak HP/TQ. That must be confusing for some

 

If you don't have the intake yet, I know someone who will be selling a JBR 3" fairly soon.

 

I'm in Canada, so I'm sure the shipping will be stupid I'm likely just going to order it along with the turbo. I've bought too many used parts now to be annoyed enough that I'm just gonna spend the extra couple bucks and know that I have all the parts

 

You should use Manley pistons. Wiseco ots have been notorious for oil control ring problems. Would suck to build and then have to tear it all back down after a few thousand miles

 

Why are you building a motor for 320whp goals?

 

My car right now is making 320/346 with BNR S3 and 93 gas. Plus im on stock axleback which is quite a restriction and stock block.

Not trying to knock you or anything, but why go built if 320 is your end goal? You need to add 200 more to that figure.

 

I agree with this and the 3.5" intake as well... max out the stock fueling at least lol.

 

Oh yeah I got 3" intake too lol.

 

I think you have a reasonable plan overall. I do second the recommendation to steer away from the Wiseco pistons and consider the Manleys. I have Wisecos right now and will probably be switching to Manleys in my next build.

You can learn more about car setup here if you're interested, keeping in mind this site is for autocross, not time attack. But it's easier and quicker to read than "Race Car Vehicle Dynamics" at any rate: http://farnorthracing.com/autocross_secrets.html

I would run the Bilstein kit as-is for now. In the future you can think about upgrading the springs and revalving the shocks, but for now you can just use them as-is and play with things like the rear sway bar rate, alignment, corner balancing, and most importantly, tires and wheels.

Ignore all the haters with regards to building. Built motors are awesome at any power level and with any turbo and fuel. I had a car with a stock motor and now I have a car with a built one, and I love being able to tune the car like an asshole and not worry about blowing a ringland. That turbo is a great choice. You'll easily make 320 whp on 93/94, probably more. Keep in mind, you will definitely need an oil pan baffle, and I would highly, highly suggest an extra oil cooler.

 

I think it's a solid plan and it sounds like you've done some research which is refreshing to see. I know all about building to a specific class, so if 320whp fits your class then it makes sense to build to that.

However, I will caution you this as this has happened to myself and many others: just because you want to be in that class NOW doesn't mean you wont want to move up later. You are definitely overbuilding the engine for the power level, which is fine, I would just advise to make sure you get the hardware you need now if you ever see yourself running in say a 400whp type class and de-tune to fit into the 320 class. People do it in the Miata racing world all the time to be able to run in multiple classes or series.

If you know for a fact that you'll be good with 320 for the duration of your time racing that car (or at least until another complete tear down and rebuild for when it goes full racecar...and it will...) then I would say proceed as is.