Had my car (90 hatch) tuned at SpeedFactory on Neptune.. Ran into all kinds off issues of my own fault during tuning but at the end of the day it is tuned at 370 hp.
The problem is it wants to overboost and hit boost cut especially in higher gears, and did it on the dyno but apparently wasn't in the tune.
setup:
Sleeved B16 built
PeakBoost ramhorn
Tial 38mm W/G open dumptube only about a foot long
57 trim t3t4
P28 Neptune chip w/ boost by gear peak at 17 PSI
Mac boost solenoid



The car had a Z6 single cam turbo in it when i got with all the same components and ran great but blew headgasket. I just changed engine, mani and turbo (50 trim to 57). Same intercooler, W/G, most of the piping, Mac solenoid, BOV, ecu/chip, as before. Was tuned to 21 PSi on the single and it ran fine. I assumed it would be a simple re tune to about the same power level..

I was told its tuned properly but has some type of mechanical boost control issue. I verified all the vac lines are correctly hooked up, and correct size, tried different Tial W/G, no change. Basically you get to full boost 17lbs and it backfires instantly and loses all power, pretty much dont even want to bother boosting on it. What am i overlooking? Would the Mac solenoid cause overboost if it went bad?

 

What spring are you running in your gate?

 

I believe its a 10 PSi spring. I never messed with the spring since it was working fine when I bought the car, I figured it still should, but this problem is actually pretty frustrating.. i can take it apart and verify it if i need to?

 

did you change the percentage for the boost solenoid?

 

During tuning im not sure.. It was at about 20lbs of boost and he had to keep turning down the boost to keep it from hitting the boost cut. He said he had to turn down the duty cycle because it was overboosting. It sounded more like an erratic boost in that the more it was turned down the better it got.. I wanted to have it at about 20-21 psi but he said at 17 it had better control off the boost..? I will ask them more about it but it actually seems to have gotten worse now that I have about 500 miles on it.. also the vacuum line for the wastegate goes to my intake mani as well, I read its not supposed to see vacuum and should be on boost piping somewhere but it worked this way before as does my friends crx with similar setup. In process of changing that right now..

 

i have my wastegate (bottom hose) routed to my vacuum block, that should ease your nerves. you may need to adjust the solenoid settings some, because it sounds like it may be high still. i use hondata so i dont know much about neptune. before you go and make some adjustment just wait for someone else to chime in on this issue.

 

unplug the boost controller and see if it overboosts. If it does then its the boost controller adding additional boost. And you can simply reduce the duty.

 

it would be ok to run it at low boost off the gate spring even if its tuned for higher boost?

 

38 mm gate on a ram horn is to small. Need a 44 or larger IMO

 

Dependent as to what size turbo and amount of boost pressure used. A larger gate is only needed if trying too use very low pressure on a big turbo

 

i have the same problem few week ago keep boost creep and boost cut just suddenly, is was my 38mm tial wastegate. one of the set screw back off inside of the WG letting bottom part air into top part of the gate so the gate won't open to cotrol boost. if you disable boost controller, it still hitting boost cut your gate is not working or too small. i have t3/t4 60 trim boosting 15 psi (boost cut at 18 psi) work fine for my setup.

 

thats interesting I have mine apart right now. Cant tell what the springs are there is no paint on them, the small one may have been yellow I can see a tiny spec on it but thats it.. Everything inside the WG looks fine to me the piston moves freely... starting to think it needs a more thorough tuning.. Ill try it with the boost controller unhooked and see what it does..

 

You can try running the small yellow and see if it makes around 3psi lol. http://www.tialmedia.com/documents/w3_tial_38_sp.pdf

 

ah i see 1 to 2 psi creep with my peakboost ramhorn depending on ambient air temp and load. however, i also had issues on the dyno with the mac solenoid sometimes id increase the duty cycle and it wouldnt do much, then on the subsequent pull it would boost up a lot more at the same duty.

sounds like the tuner did it right by reducing duty cycle to prevent overboosting. just wondering though, a sleeved b16 can handle more than 370whp, as can the turbo. what was your limiting factor that would make it so the cut couldnt be raised 1 or 2 psi to prevent it from being hit.

 

well it came down to time at the end, i left one of the rocker arm pins out and vtec wouldnt work and they did me a huge favor and fixed it on the dyno, as well as new dizzy and vtec wired wrong and a cam gear slipped during a pull..it was a long day.. it was nearing 5pm so I was told I needed to figure out why its creeping uncontrollably and it was otherwise "tuned"..
So now I just drove it with the boost control unhooked and it stays rock solid at 10 lbs boost so I think its either the mac solenoid or more tuning I guess....
___"however, i also had issues on the dyno with the mac solenoid sometimes id increase the duty cycle and it wouldnt do much, then on the subsequent pull it would boost up a lot more at the same duty.___" this is exactly what happened, he was saying he could change settings but the boost just did what it wanted, what did you do to fix this? Should I get a different solenoid before I take it back in?

 

I agree to an extent. Generally manifolds on Hondas don't have the wg placement priority. Usually a small gate creeps from my experience with short rams and ram horns. But that doesn't mean they all will if like you said the exhaust wheel is more of a restriction and pushes exhaust pressure to the wg

 

x2 on the gate's priority. I've also heard from reliable sources the key to making a smaller gate work is a good, stiff spring (say 16lb. or more). Of course that defeats any hopes of traction on street tires.

 

WG placement and valve size really plays a huge role in controlling the proper boost as per spring rate.

way back 09, i was tuning a built motor, afi ramhorn, gt3582r, 38mm wg and drove me nuts LOL

despite of changing the wg's springs using different spring rates, boost keeps creeping +7 to +9psi max.

hacked the mani's wg tube then replaced the 38mm w/ a PTE 44mm and never looked back. boost was steady all the way with merely +1psi creep tops.

here's a good old thread you might find useful.

https://honda-tech.com/forums/showth...ciation&page=3

just reread your specs: Tial 38mm W/G open dumptube only about a foot long

i suggest you add more length to your dumptube so your turbo won't suck in the dumped hot air. past the oil pan is more than adequate or out of bumper's if sideways LOL

 

ok thanks well maybe ill look into a 44mm gate, some searching I find alot of creep issues with 38 on a Peakboost ram so maybe that is the answer