Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

Gave 2nd gear 10psi yesterday and she spins but accelerated quite nicely. Plugged in my BBG table we built and on the street she loads quite a bit more. Immediately hit boost cut (18psi). A third gear pull starting at 3k and quickspool set to 12psi it pulled great and loaded up to 17psi settling at 16 which I’m happy about. Guess the dyno just didn’t quite load as much as street. During a shift from 2nd to third and the quickspool on he smashed boostcut so I may need to lower it since the turbo spoils pretty quick anyways.

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

I had same issue, no boostcut reached on dyno. Once on the street hit boost cut like crazy. Slowly adjust your DC down. depending on how you were tuned you may be able to increase boost cut but you will need to check with your tuner ( I always tune for higher pressure ratios and increase cut slightly over what I target) different roads and ambient temps will cause the controller to act slightly differently day to day

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

I kinda skimmed through your post here again and still didn't see mention, (I may be getting old. Lol) what engine management? Hondata, Neptune?

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

edit...noticed my comment today was the exact same as the last one I made.

Great work

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

he’s on s300

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

He wrote down the duty cycle for boost levels during the pulls. I plugged them into the chart but was over boosting on the street. Tweaked them a bit today along with the compensation table. My boost cut is at 18psi. Just did some short full throttle pulls in third to see turbo spools on on a log. Hard to find on the internet as everyone uses bigger turbos but is 340wheel good for a gt2871 on a GSR lol. Regardless the car feels great and AFR’s are good in the 17psi realm. Tuner said I’m good to 18psi.


https://cimg6.ibsrv.net/gimg/honda-t...496776283.jpeg
https://cimg8.ibsrv.net/gimg/honda-t...070c85ced.jpeg
She builds as high as 17.7 but holds at 16.5 on the street. I’ll get a full pull log in the upcoming days

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

Pro tip feed your AFR's into your s300 makes datalogs infinetly more useful

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

where’s the thumb up and like button for this.

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

they are, I just changed the template to show these 3 values quick for this post :)

https://cimg7.ibsrv.net/gimg/honda-t...4a18339c3.jpeg

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

So maybe I'm just bored and overthinking stuff. I went over the last dyno pull that basically made 340/220. it hits 17.2psi @ 7440 and then peaks at 17.4 but drops to 16.7 @ 8100 and rides that out to 8600rpm. On the street, she hits 17psi @ 6000rpm and grows to 17-17.7 until 8100 and drops to 16.8 which rides that out 8600rpm. So on the street, she makes the 17psi 1500rpms earlier than the dyno. From what I've read and that's tough because people will say oh I make full boost by XXXX rpm but are they actually logging and looking or what which I will never know. The car drives and feels great I'm just wondering if I should have faster spool / more power than what I'm making. Are my Tuner 2's to big of a cam for this setup...really contemplating tweaking the cam gears as I just degreed them to the centerline and have left them. Some folks say overlap is good, some say it is bad...sorry for the rant just pondering things :)

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

When I say boost builds, this is when I hit positive pressure (.5psi) at say, 3300 rpm, then full boost (24.5-25psi) by 5500; I am logging the run in Neptune and this is what I captured. It is also ran on the street. I believe you're experiencing (dyno roller vs street) an effect similar to running on a treadmill vs running on the sidewalk. You're not getting the FULL effect on the dyno roller as you would on the street; the engine load is not the same between the 2. I may not be explaining properly but, you may get the idea.

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

Oh yeah I 100% get ya, so I may be closer to say 350wheel but the cars just not “loading” as well on the dyno. So in your case your building more boost earlier with a bigger turbo I believe. I do know it was also tuned “conservative”. I should just enjoy driving the car which I do but I’m just a tinker person :)

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

Tinkering can be a double-edged sword. Lol!

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

For a turbo your size I'd say the Tuner 1's would better suite your setup. Or just ITR/CTR's cams.

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

Spool seems slow given turbo your using I hit 17 psi between 4.5 to 5.k on same motor larger turbo itr cams.

Have u done a proper boost leak test? Your cams seem a bit large given turbo used but I don't think it would cause this particular issue

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

i debated those first As I wasn’t sure if I ultimately was gonna go with a gt3071 or this 2871

i actually have not but funny you say that because I that will be performed this Saturday. I’ll update the post with my findings

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

Something doesent sit right with your spool time should be spooling twice as fast imo.

Boost leak test get a pvc end cap and drill a hole to mount the air compressor fitting then attach to turbo inlet. Regulate compressor air pressure to 5 or so psi higher then max boost. Get soapy spray bottle and test all fittings. First time I did this I had alot of small leaks at piping fittings and even intake manifold especially the thermal gasket

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

Sort of what I assumed on spool time and was wondering if I either A had a leak still somewhere or B the cams and maybe they need to be played with on the dyno. I am actually running a thermal intake manifold gasket. Not sure if it’s a Skunk2 one or the hondata one, I believe the Skunk2 one as it came with the intake manifold. Excited to test on Saturday.

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

cam settings might change things abit (i would say set at 0,0) however I haven't had much spool differences when playing with cam timing. this is on ITR cams which do have some overlap but not quite as much ans the Tuner 2's...

you could always sell your cams even if you take a loss just bite the bullet - GSR cams are cheap and would probably overall perform better with the given setup

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

So I performed a boost leak test and the tester wouldn't even build any pressure. I found a leak by the IACV so I fixed that up and then the gauge started to read. I also went from a red tial wastegate spring to a yellow so I should have maybe 10lbs of boost on the gate now. Changed it to see if it aids in a different spool time, also noticed when I degreed the cams I did the intake centerline to 94 degrees. Skunk 2's site for the exhaust says 105 degrees as the rest of every retailer selling them has 112 degrees. I degreed the exhaust to 112 degrees and got my +3.5 degree on the cam gear. Dyno graph still has a great smooth linear powerband but ill report back if/how much fixing that iacv leak helps. I think I may just be chasing nothing unless these cams are making it spool slower but yet still smooth.

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

Not sure what you mean by tester won't build pressure. There may be something at play here. Iirc I used my boost gauge to monitor pressure.

Did you use soapy water? That should show u whats going on spray it anywhere you can think of

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

the leak tester I put where my filter sits. It had a pressure gauge on it. I need another set of hands as the fill valve I have to hold the attachment on. It held pressure but slowly bleeds off now. Gonna reinvestigate tonight. I’m assuming if I get the gauge to read 10psi it’ll hold it there or how slowly should I expect it to bleed off? If that makes sense

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

It will bleed off from opened valves out the exhaust.... You need a air compressor set to target pressure.

so it gives conious soure of air - no fill valve just set your compressor to regulate pressure

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

ill set the air compressor to 20psi, have the wife hold it on the fill valve for this tester and I’ll check the boost gauge along with listening and soapy water. Appreciate the help

Re: mynameisjustin and here is my CRX B18C1 GT2871R Build Thread
 

So set the compressor, wife held it filling and boost gauge slowly crept up to 20psi and stayed as long as she stayed putting air in. Removed it and it slowly bled out. Going to try it again tonight and start spraying everything with soapy water because it appears and sounds like no audible leak except the air going through the pipes.

in the event I don’t find any I’m going to assume the tuner 2 cam just is to big for the GT2871r. Granted the powerband via the dyno is 100% linear like an NA car so that’s great. Just at say 16psi with a smaller cam I would probably maybe maker a bit more peak horsepower assuming it would spool faster. If I did that than street traction would be more of a battle I assume.