Like the title says, I will soon be starting a turbo build on my gsr. Motor is a 94 Gsr swapped into a 96 civic. Motor was rebuilt two winters ago (2012-13) with the expectations to boost it stock on a small setup, so it was just basically a "refresh". All new OEM Honda gaskets, Oem oil pump,water pump and timing belt, ARP headstuds, Mainstuds and rod bolts, ACL bearings, hastings rings. So the motor is fairly fresh. Was told by the mechanic it didnt need to be bored out, he was just going to hone the cylinders and it would be fine.. Motor only has about 7000 kms on it and is still burning oil. So i'm assuming the cylinders are out of round and it will need to bored out to 81.5mm. Just wondering what your guys\ thoughts on this was?

In saying that, If I do bore it out, I will be going with low compression pistons and rods to prepare for boost. Just wondering what the best piston and rod combo in a boosted gsr would be? Looking to be in the 9's for compression ratio. I have my eye on CP Pistons (9.8:1) and Eagle H beam rods atm. Any feedabck at all is appreciated!

Also, while rebuilding the bottom end again, I am tempted to do the head as well. Don't really have a plan for the head yet, so I am open to any suggestions on cams, valves, springs, etc.

I am and will be running the car on 91 octane (supreme pump gas in nova scotia, Canada). Thinking about running a gt3076r turbo and hoping for atleast 300+whp. Again, all suggestions are welcome, just trying to gather info before I start buying parts and then have to sell to buy better. Thanks Guys!

Heres the car and the motor to keep it interesting lol

 

CP/Eagle is a good combination. Personally, I'm running Wiseco/Eagle in my build.

You don't need to lower your compression - that was an issue back in the days before real tuning options, but with all of the great hardware and software options on the market now, you absolutely don't need to drop compression. Stick around the 9.5:1 to 10:1, and you'll have good, usable power both in and out of boost. Don't forget the hardware, too! Nuts and bolts may not look important, but they're really the most important part of the motor - one bolt backs out, and your motor will turn into a piece of modern art very quickly.

A 3076 will be a little bit on the big side for your goals, but with a properly built, forged bottom end, you could definitely use that turbo and engine to get up to 400 BHP.

 

i agree cp 9.8 and eagle are ok.

3076 is a good turbo, i would prefer a GTX3076R for your engine. For a low cost turbo a cheap T04e 50 trim, or 60 trim, or holset HX30 would do the job

 

Sweet setup, bro

 

I too think 9.8 is a little low. I would go to the next step up, something around 10.5:1. With proper tuning you wont have anymore real risk, and you will get more power out of boost, faster turbo spool, and more power with less psi. It's a win-win.

Also, DO bore it out to the next oversize. 81.5mm would be good. Make sure you also replace the valve stem seals. They are only ~$20 for all 16 from honda.

 

I used the GT3076R on a 300WHP set-up and loved it. If you are tuning on 91 octane I would go easy on the compression for the simple reason the octane rating on pump gas isn't always accurate.

 

Thanks for the input guys! Greatly appreciated. Stock compression on a JDM gsr is 10.6:1, but the reason I said 9.8 with the cp's is because on realstreetperformances website, in an 81.5mm bore, they offer 9.8:1 or 11.0:1 but nothing in between.. And id rather lower the compression for a boosted street car vs raise it.. Maybe if it was a race car lol

Also forgot to mention in the original post that it's currently running on a p28 ecu with hondata installed so it will be getting tuned with that.

The valve seals and all hardware have already all been replaced with ARP hardware and OEM valve seals when I rebuilt it, and new rods come with new arp bolts. Do you guys think I should do the valve seals again for the hell of it?

 

No point in low compression anymore. you could run 11:1 on 93 and still make 300 easily. with the 11:1 pistons you can also play around with chamber volume and headgasket thickness to get it down to 10.5:1 or so.

 

For 11:1 you need to make sure your tuner knows what he is doing. Or has a really really good rep.

 

that is true... a shitty tuner can kill a motor faster than any compression ratio can lol