I've got a d15/y8 mini me in my 91 rex and I'm almost done getting my 14b turbo kit together. Waiting on a fuel pump and chip money.
The motor has a z6 intake mani with b16 throttle body port matched, stock y8 head and d15b bottom end with arp head studs and arp rod bolts along with a mls y8 head gasket.
I believe my compression is around 10.5:1 with my set-up and I think the 14b's boost over 10 psi (12 psi isn't?). I'm just trying to figure out if I should risk running the motor at these boost levels right now or should I turn the boost down until I can piece together my built D16 bottom end and not risk hurting my motor or turbo. My gut says turn the boost to 6-7 psi and wait for the d16 block to be done, then turn the boost up to stock.
Any thoughts? And I'm not 100% sure how to lower the boost on a completely stock 14b still with the internal waste gate. Can any one tell me how this is done?
Thanks for the help!

 

any thoughts?

 

i would say run it off stock wastegate boost, no boost controler to up boost.If i remember right straight wastegate is 9 lbs, or close.

Just for reference i ran my stock everything d15b2 at 10lbs on a t25 no problem.

I think you will be fine.

 

Even at the 10.5:1 compression, that's a bit higher than the stock D15b2 compression. If I were in the 9.5-9.8:1 compression range I would be ok with the 9-10 lbs the 14b puts out, but I'm new to this so I may be wrong on my thoughts.

How would I lower the boost on the 14b if I go that route?

 

Hoping to get a few more answers....

Does anybody think that it would be safe to run 8-10 psi (most stock 14b's run at this boost pressure, I've done some more research since i first posted this thread) since my CR is at 10.5:1 I think that's a bit too much boost. So by shortening the rod on the waste gate I should get a lower boost level right? I've heard this may cause lag though since the gate may be partially open all the time or more of the time anyway. Would this be the best way to limit the boost from the 14b? I've heard of the second spring method, but which way works best?

 

??

 

Miss my old set-up with a 14b turbo. It was great for dd, full boost around 3.5. Had no problem with 10 psi on the stock d15. The weakest link on d15/16 are the rods, they snap like toofthpicks over 220ish. If your boosting around 10 psi, you should be around 190 whp give or take

 

Thanks for the reply. I agree the rods are the weakest link for sure, but my motor isn't just a stock d15. It's a D15 block with a D16Y8 head which bumps my compression to 10.5:1. That's my worry is will the 10.5:1 and the possible 8-10 psi from the 14b will that be too much??
And what's the best way to drop the 14b's boost down to around 6?

 

Have close setup to you...stock d15 motor...I ran 10psi dd with no problems..Only thing I ran into was over boosted and blew the hg...Other than that tuning is the key...10psi on a 14b isnt going to make that much power..

 

What was your compression ratio? Was the whole motor a D15 (head too)? I'm not worried about how much power I'm gunna make, I just need to know if I'm running too much boost at 10.5 compression...

 

What are you doing for fuel? fmu? 10:5:1 is alittle high for my tastes with stock rods on any boost level.

 

fuel is just being handled by a walbro 255lph pump, stock rail, stock fpr, 440 precision injectors, and a chip from pheriable until I have money to tune the car.

For 10psi and under I won't need to upgrade anything else on the fuel side of things. I think 10.5:1 with 10 psi is too much, but I am new to FI so I don't know for sure. I would think 6 psi would be better, but I don't know a good way to limit the boost of a stock 14b to 6 psi. Any suggestions?

 

if your looking to limit your boost you may want to just tune with a boost limiter so it cuts your boost off at what you want it at. im not 100% sure how the tuning works for that but I was reading on it earlier

 

if you run the stock exhaust piping that will help lower boost level too. i was hitting 10psi on a 14b open downpipe and 6psi with the stock exhaust (w/ cat) hooked up.

 

Terrible One:
Yeah I guess I didn't think about the exhaust helping to limit the boost. I have a crush bent 2 1/4" exhaust right now, no cat though, but that should help over a bigger exhaust that I'm gunna get down the road. I have a cat I can through in to help with that too. Thanks...

shluder99:
What's a boost limiter?? Never heard of one, I know boost controllers, but that aids in upping boost, not limiting. Have any info or threads about em?

 

only thing i can think of is remove the internal wastegate and get a manifold flanged for a 38mm external and run a low boost spring 5-7psi should be fine

 

That's an option... can the waste gate on a 14b removed? Or blocked off? How would you do this?

 

have a 14b wastegate welded shut(the little flapper)
get a downpipe flange and make a new downpipe

thats what i did

 

Yeah I guess that's a way to do it, at the moment I'm looking to do this on a budget and add things down the road. Don't think that's the route I'm gunna take. Thanks for the input though...

I have a friend saying I should do a water/meth injection to keep myself safe at those boost levels and compression. I might look into that more. Anybody do this on a boosted honda?

 

doing water/meth injection and having it tuned would cost just as much as buying a cheap used log and used external wastegate

 

That's true, I've been thinking about it more (welding up the wastegate and using an external one) and I have some friends who can weld damn good, so that'll be cheap and the manifold I have is fitted for an external waste gate. I'm half way there I guess, might as well find a decent used one or a new one on wicked sale and go external. Has anybody done this with a 14b before? I don't see why it wouldn't work, but does it cause issues with flow, spool, heat build up, etc.??

 

ive seen a bunch of people do it and ive done it my self on a 14b and a 16g

have you buddy weld you up a nice downpipe too. someone on here sells a 14b exhaust flanges

on my STOCK z6 i was pushing like 16lbs on a big 16g for a few months lol i think your car should be fine

 

I'm just worried about the compression ratio. Stock Z6's have 9.2:1 compression I believe. A lot more boost friendly.

I do think I'm gunna go this route the more I think about it the more it makes sense. And you say you've done it with no problems. One of my DSM friends say it should be fine, so F it, I'm doin it. Thanks for the help!

 

Why not just get an actuator that opens at a lower boost level?

 

while tuning have a det can hooked up (detination can). it helps you hear knock

so youll know if your running too much boost/timing

also the evo3 big 16g turbos are flanged the same as the 14b and are a nice little upgrade from the baby baby 14b lol