boost question

[sr240sxs14]

I have a redtop in my s14. I am currently running a hks evc boost controler and it is set at 60 kpa right now. i am running a t2871r with a hks actuator. when driving on the high way when i get on high end rpms like 6,000, 6500 its sputters, hestitates if that makes sense and stops running boost. I thought it was a boost leak since 60kpa is like 8.7 psi of boost. any thoughts to whether this is a correct approach or is it something different. thanks

[Hashiriya415]

Try changing boost to like 5psi or 10psi or 15psi, see if there is any difference.
Assuming you got more fuel flowing for the more bigger turbo.

[Silentoreo34]

What are you using to tune with? Are you running bigger injectors(If so what size)? need a little more knowledge of what your running to figure out this problem.

[naw_speed]

had the same problem wit my buddy's s14. his was between 4k-45k rpm. just an easy check but pull the plugs and check the gap. even iridium plugs can be to much gap for the applications you are using... it fixed the issue with my buddy's s14 and we have no more problems.

if not.. good luck!

[sr240sxs14]

I been running stock injectors with stock tune and so far the fuel to air ratio and been almost exact 14.7. thats also why i been running only 8 psi until i get a standalone and injectors. I replaced my t25 because it started to smoke a little so i bought a t28 knowing in the near future ill be buying a stand alone and injectors. i didnt check the gap but I will so far I lowered the boost and its been better so I am guessing I was running to much boost, but im going to check spark plugs as well just in case.

[koukimonster139]

your blowin out your spark breh

[sr240sxs14]

blowing out spark?? like to much air to fuel ??

[Kingtal0n]

the oem injectors cannot support that sort of flow. you are probably ruining your engine, and hitting maf cut. the A/F ratio needs to be about 11.5:1 not 14.7 during boost. I pray you have OEM camshafts.

[sr240sxs14]

Even with 8 psi figured if I run low boost it should be ok. it runs 14.6 at idle and goes to 12 in full boost runs lean when coasting its almost exactly the same as the t25. But when it surged it was at high boost like 12 psi and 10 psi. Then I turned it back down and its been ok

[di-devol]

If your 12 in boost, that's fine. Sounds like you're blowing spark out like sr240sxs14 said.

What's your plug gap?

[sr240sxs14]

Not sure on the gap but I am going to check it tomorrow thanks for the inputs its helped a lot

[Kingtal0n]

If your 12 in boost, that's fine. Sounds like you're blowing spark out like sr240sxs14 said.

What's your plug gap?

He has a REDTOP with OEM Injectors and a gt2871 turbocharger:
I have a redtop...i am running a 2871r...

at just 7psi that compressor is capable of flowing more than 30lb/min.
those injectors will not support that kind of airflow!

He probably maxing his maf, and having lean situations that we are not aware of. It is not safe to run any large turbocharger at any boost pressure with OEM injectors!

[sr240sxs14]

I have a z32 maf and ill be buying injectors in the next couple weeks what size inectors do you guys recommend? And I was planning on purchasing. A cc or does some one recommend a different standalone that is around 1k.

[EsChassisLove]

740cc injectors.

Check the plugs yet?

When I put my 370cc stock injectors back into my engine, built with a 2871, at 5psi I was hitting 100% duty cycle in those injectors according to me PowerFc. 8 is waaaaay too much.

If you want a good standalone get AEM. I'm about to make the switch.

[sr240sxs14]

No I haven't im going to check them tonight and ill let you know so arm with 740cc injectors. What brand do you recomend I wana get a decent set. For aem stand stand alones don't you have to rewire the engine harness? I bought a new wiring harness from wiring specialist from frsport. So I could plug in the z32 maf with out hacking the wiring. Lucky I been keeping the car in the shop last couple years so its not driving very often so there is maybe 500I miles on it since I put this turbo on.

[EsChassisLove]

AEM EMS S2. Plugs right into the original harness.

As far as injectors, Nismo, HKS, SARD are your best and most reliable/affordable ones. You can snatch a pair of used, clean/flow tested Nismos for under 400.

[sr240sxs14]

AEM EMS S2. Plugs right into the original harness.

As far as injectors, Nismo, HKS, SARD are your best and most reliable/affordable ones. You can snatch a pair of used, clean/flow tested Nismos for under 400.


Awesome info ill will do that thanks. Looks like ill be parking it for a little while more thanks for all the info for everyone

[jr_ss]

Sard are your best option. Best injectors to run on a factory rail. Larger windings offer better fuel control.