So after a lot of set backs I am finally getting ready for turbo. I have decided Gtx2867r for my b18c gsr. Now I know that stock internals will support around 300 whp but most of the stock internal builds seem to be for fun/daily with no track abuse. So should I build the bottom end with forged rods/pistons or leave it alone? I know a factor in reliability is in the tune but my goals aren't too crazy and not sure if built block is necessary. I am going to run some hill climbs and track days (hopefully start working on competition license).


Also, if I do build the bottom, should I do valve springs/retainers? I will be using stock cams for now. Any into is helpful. Thanks!

 

I would go ahead and build a forged bottom end for reliabilities sake. If youre staying with the stock rev limit and stock cams then stock springs etc will be fine.

Btw for only 250hp wont a gtx2860r be a better choice?

 

If you'll be abusing the motor, some basic rods and pistons can't hurt. Just remember, reliability is all in the build quality at that point - **** up tolerances, and your freshly rebuilt motor will grenade with a quickness. Also remember that you can't use aftermarket rods on stock pistons - upgrade one, you have to upgrade the other.

For stock cam, you don't need to upgrade your valve springs and retainers, but while the motor is apart, you should go ahead and replace your valve stem seals.

 

I got adice from theshodan and he advised gtx2867r or gtx2871r. I told him I wanted 250-300 who and those are what he advises *shrugs shoulders* and thanks for input.

Alright thanks. I did stem seals 500 miles ago so I'm good there.

 

For that power level I would just run the stock engine. It will most likely be fine but build it if it blows.

 

Spend a little now, or spend a lot later. If the engine blows because the rods couldn't handle it, they'll probably take the block with them. You'd feel pretty foolish if you could have avoided spending $150 plus labor time because you didn't want to spend the money now.

 

Well, I already have Eagle H beams so I just need some JE pistons to go with them. I just didnt want to take my motor apart again lol. I had the motor out a few months back to do ARP head studs (was going to boost 100% stock) but then I got the rods for cheap so I was just debating building the bottom end or just keeping stock and taking my chances. Based off the above suggestions, I am just going to be patient for a few more months and build the block.

 

JE, Wiseco, Supertech. All good options. If you already have the rods, get the pistons, spec new bearings, reassemble, and go with it.

 

It sounded like Shodan had recommended that since that was the turbo noted for quick spooling upto the 350 whp range on a B18C and the GTX2863r for a B16

 

Thshodans mostly never wrong. Iirc the spool times between the gtx2867r vs the gtx2867r are negligible so getting the slightly larger of the two would give you a little more play room with power

 

Especially in regards to circuit/track racing...that's kind of his thing. I would take his suggestions and run with it. I've purchased turbos from him based on his advice and would highly recommend him to anyone

 

Yeah I trust Shodans advice. When he replied, it wasn't a few word reply. He explained why (at that time I was debating disco potatoe and 57 trim turbo) the Gtx2867r was better overall.

What compression ratio pistons should I get? I was thinking 9.1:1 or should I get forged stock compression? Suggestions?

 

i say just stick with stock compression. I kept my turbo b18c1 stock when I was tracking it. Never had an issue.

 

10:1+ but it depends on the fuel you plan to run

 

91 octane. If I do stock or 10.1 compression I am going to have to use flat top pistons correct? I researched the different types (dish, flat, and domed) and flat tops seem to be what I'll need.

 

Most pistons come with information on there compression ratio

 

I know that but does it matter between dished, flat, and domed pistons as long as I achieve the compression I am looking for? Flat tops have the compression I am looking for. I just wanted to make sure that flat tops will work without any hassle. Anyway I think I figured it all out.

 

If the reliefs (if needed) are enough for ur valves ur set

 

It doesn't really matter about compressor size with the gt(x)28xx turbos. on your typical b vtec motor the turbine wheel size will limit mass flow to around 420-430hp, this was with a 56trim 2871r...

you have to remember the gtx series still uses the same gt turbine wheels, if you can make the system more efficient with a larger turbine housing and other tricks you can squeeze a bit more out of it but ultimately the turbine wheel size dictates how much exhaust can physically leave the motor at a given rate.

 

OK thanks for all the info guys. Much appreciated. I have another question but don't want to start a new thread. I bought a used Tial 38mm wastegate last night. I need to change springs for it but I am not sure how much psi its going to take to reach 250-300 whp with a gtx2867r. Any help with determining spring size is appreciated. And I read off an evo forum that you (for example here) if you plan to daily at 20 lbs then get an 18-20lb spring. Is that the right way to determine spring size?

I plan on getting manual boost controller to get me started so I won't be messing with boost settings at all. Once I get tuned, I'll leave it alone as hard as it may be

 

why get a boost controller anyway if you're not going to mess with it. get the right spring and just run off wastegate.

 

All questions I am still looking into. I wasn't sure if a ebc or mbc was necessary. If I don't need one at all, I will save my money until I can get a good electronic one. Then in that case, I just need to figure out the proper spring for my wastegate.

 

Boost pressure doesn't matter much, power level does. run whatever pressure it takes to make the power you want.

power vs psi varies wildly depending upon setup, fuel, and tuner so you won't have much of an idea pressure wise until it's time to tune.

 

So just use whatever spring is in my wastegate when it arrives and change it after the tune when I know how much psi was used for my goal? Sorry but I am 100% new to turbo.

 

Well, a rough ballpark starting point for the power you want is 10-15psi... lots of factors play into it.

you'll need some sort of boost controller (electronic is better imo) in order to raise pressure.

Do you know what spring is in the TiAL? take the top off and take a pic, It's either a small or large spring and it should have colored paint down one side, that tells you the psi of the spring. report back with a photo and we can narrow it down.