So I’m putting in a 135k mile y7 into my 99 civic just to get her going again, and I will be pulling the old motor for a full performance build, looking to build somewhere in the ballpark of around 250-300hp, obviously going with forged internals, better rods, head studs, get it honed, turbo and manifold, what do you guys suggest for internals and should I run a chipped ecu or just toss all that and run a stand alone system?

 

I haven't had a turbocharged D-series before, but I've done B-series and H-series. If you want to go the cheaper route there is the Vitara pistons which are supposed to handle up to 400hp. I've never used them, but lots of people have. Wiseco pistons will cost more and can handle 500hp which is more than your goal. But remember, if you want to be comfortable with 300hp daily, then you want an engine stronger than your power level in case it boost spikes or you get more power than expected. CP and JE pistons are more expensive than Wiseco, and can handle more power. I'd recommend the Wiseco pistons with Eagle or Skunk2 connecting rods. I've used Wiseco pistons and Eagle rods in an H22 making over 300hp daily, and I had no problems with them. It also boost spiked a few times and put lots of strain on the engine. This page gives you an idea of pricing and what you get: https://www.speedfactoryracing.net/c...series-engines
For the D-series, there is a main girdle on the engine block that will need to be notched to fit bigger connecting rods, unless you go with the speed factory "no notch" rods, but they appear thinner than the other connecting rods. You'll probably want to get the block "decked" as part of the machine work that can be done while you get a bore/hone.
Of course you'll want a new oil pump, bearings, gaskets, etc....Oil pump-Honda is recommended, and bearings also. Gaskets, people have had issues with turbocharged D-series blowing head gaskets before. The stock or Golden Eagle headgasket on a turbocharged D-series is something I've read of having problems at higher horsepower levels. Go with a JE Pro seal head gasket or maybe the Skunk2 head gasket.
For a turbo, I recommend keeping it simple and cost effective by not using a ball bearing turbo. Although the spool about 500rpm quicker, they often need a coolant line fed into them, and are more pricey. I've used Garrett T3/T04E 57 trim and I liked it on a B-Series. I'd go with a .48 A/R ratio with that turbo if I were doing a D series. 60 trim might be too slow to spool. and a .63a/r would be the same-plenty of power but a little slow to spool on a d series. I think I was using a .63a/r housing. I'd recommend a Garrett T3/TO4E 50 trim, with a .48 a/r. GO-AUTOWORKS Garrett T3/T4 50 trim That's the best price $685 I've seen for a while on those turbos. I'd strongly recommend not going with an off brand/no name Ebay turbo, and also don't go with a $1k plus fancy turbo.
Exhaust Manifold- you need to decide if you need the air conditioner or not, then go from there. To retain A/C, it's more of a headache to cram all that in there, but it is doable with more money and time. For 300hp, I'd go with a mini-ram manifold. If you need a/c, then you'll also go with a smaller compressor housing for the turbocharger, which limits you. Most manifolds that are a/c compatible need to use the "B" compressor housing such as T3/T04B, which is smaller than the TO4E. TO4S is bigger than the "E" and isn't needed for a d series pushing 300hp, just fyi. Here is the manifold I'd use GO-AUTOWORKS Mini Ram T3 Turbo Manifold Civic Integra D16 B16 B18 B20 H22 F20B
If your cylinder head is in good condition and working, then I'd recommend just using the stock one and not spending the money on valve train, intake manifold, throttle body, cams, or port and polish. You're better off spending money elsewhere for 300hp. As long as you don't increase the redline, or hit the rev limiter too much, the stock cylinder head is adequate.
For computer, I'd usually say go with a chipped ECU such as Hondata, but you will need to convert to OBD-1 to use most chipped ECU's. A stand alone such as AEM EMS will be more than you need, but is also good. It just depends how much you want to spend. For 300hp, don't go with a piggy back controller. The piggly back controllers work good for maybe 8-10 psi of boost, or up to about 230hp, but as you need more fuel and ignition timing control the piggy back controllers get limited in their ability.
If you are doing your own intercooler piping instead of getting a turbo kit, I've used ATP turbo before for couplers, aluminum piping, and t-bolt clamps. Catalog Home | atpturbo.com
For intercoolers, go with one larger than you need for 300hp to help keep air intake temperatures down, which will let you achieve 300hp on 93 octane gas more easily. Not something huge though, or will cause turbo lag.
I was considering doing a D16Z6 turbo until recently. I decided on a B18B, but for 300hp, you're better off not doing the engine swap. What made me change my mind was the cost of machine work and labor that goes into a D series. I chose not to put all the money into a dseries and just go B, but that's because my horsepower goals are more, as well as other choices.

 

I recommend Eagle rods / CP pistons in 9:1 or 10:1 CR - you can get both rods and pistons from Real Street for under $900. Go with a 75.5mm piston, and send the pistons to the machine shop with the block for boring. Stock sleeves, no block guard. If you've got the money, CSS for extra insurance.

ARP 10mm head studs are fine - just stay conservative with the tune.

For your power goal, keep the head as stock as possible, including stock cam and stock cam gear. Save that money for something else. Get a valve job done with your stock valves. I honestly don't even think you need to change springs/retainers/valves.

I would convert to OBD1 and run Hondata S300. Make sure whatever ECU you choose is supported by your tuner.

The best quality turbo kit for the best price I know of right now is the Go-Autoworks Street kit. Name brand journal bearing turbo, cast manifold, and everything fits.

Don't forget about a clutch, injectors, etc.

 

what motor?

another y7?

z6? y8?

 

yes it will be another y7

 

I'm stock running an S300 on my y7 and it's been really easy with plenty of resources available online. It ultimately comes down to your tuner in my opinion, but YMMV. Really easy to get the s300 working on stock wiring harness too.

I'm using Goautoworks' street journal bearing kit, with the Garrett Gt28 .63 a/r turbo. My car is mainly for track days/street driving, so I've kept my application relatively low boost/hp, ~7psi 175whp and reliable as possible for a stock block. I have no complaints with spool time or "laggy-ness" with this setup. Coolant line routing for the turbo is a pain, but I wouldn't let it dissuade you. I get into boost around ~3krpms. If you're looking for something less jack of all trades, then I could see you wanting a ball bearing or smaller turbo to get into full boost quicker.

Side note, I kept all my A/C components if you're needed to see what my setup looks like, you can check my build thread.

 

swap intake manifolds
convert 3 -> 2 wire iacv
750cc+
oe MLS headgasket

a basic vitara setup will get you your goals.

EMS depends on your budget and your end goal.
if you are not planing to further build, then no reason to run a standalone.
old school tuning on crome, set it and forget it.