sr20det lag, full boost @ 4k RPM

[bl3ujay07]

UPDATED LAST POST. PLEASE HELP!!!

I need some help/ advice from fellow zilvians again.

So, long story short, thought i had spun rod bearing, then thought i messed up cam shaft and rocker arms. Took it to shop (Phill @ speed of sound in sacramento, ca) and he basically tore the whole engine apart. Everything interanlly is in really good condition, the problem was a piece of silicon was bocking the oil passage to the rocker arms and cam shafts. That one piece of silicon cost me $550, but atleast i know its all good now.

So b4 he reassembled the head, i bought some used greddy ras (which i think might/can maybe be a factor in this case) and had him installed it. He said the break in time should be about 50 miles, still in break in time, but i notice the car to be lagging ALOT. I notice that when i hit the gas pedal all the way, it will lag until it get somewhere near 4K rpm and then full boost no problem (stock t25)--not getting it to redline. Before, there was no lag but now, its like a N/A until 4K rpm.

My questions:

1st Q: Is it just because the car is in the break in period that it is acting up like this?

2nd Q: Can the ras cause this too? They were a used set of greddy ras. I am thinking they MIGHT just need to re-adjust to my engine and needs a break in time too, but can this be if its lagging at low end and not all the way?

3rd Q: Is there anything else i should check for? I mean i KNOW the turbo is still good b/c no shaft play and no smoking (pretty new).

Answers: ______Your answers HERE______

(internal) MODS:
s13 sr20det w/:
greddy ras
hk step 1 264 cam shafts
greddy valve springs

*also, radiator fans can slice and dice. Shit spliced my finger open no stiches tho.

Thanks my fellow zilvians.

[smelly240]

check ur timing...

[bl3ujay07]

^^^ He did my timing right when i was about to pick up the car (as in i saw him do the timing) but i'll double check. Any other suggestions. Help GREATLY appreciated.

[flip3d]

boost and/or exhaust leak?

[bl3ujay07]

I might have an exhause leak but i am not posssitive. Will get it checked out and get back. Could exhaust leak really cause car to lag untill 4K rpm tho?

[mikez97]

boost leak will

[djgrasman]

hey whats goin on.....i seem to find myself having a similar problem....its weird sumtimes when i hit the gas it doesnt pick up at all.....i hear the turbo spool but no power, also my AEM wideband reads -.- nothing....now when that happens i will lift off the gas a little and it will pick up speed and read an average reading of 14 throught 15 A/F.....wtf is wrong hear? boost/exhaust leak at a specific pressure?

please gimmie sum ideas of what this could be......

[bl3ujay07]

I have a feeling it MIGHT be a little boost leak. I drive and slowly accelerate and i KNOW air is leaking. You can hear it whisper until it hits around 4k rpm and then, boost no problem.

So i opened the hood today/tonight/now *8:37 pm pacific* and do a quick twist/pull on the throttle switch, and i hear a whistle from the where the intake and hot pipe area is. One thing is my bov is not recirculated and i have the stock rubber intake so i have to seal it up (my brother just put a large cap from a bottle and clampped it). I am going to take off the intak, maf, filter, and hot pipe and install them again to see if it changes.

Do you think this can be what is causing this lag? Can this ghettoness cause the lag? What is everyone (whos bovis not circulated) uses to plug up that whole?

[bl3ujay07]

I guess it wasnt intake nor hotpipe. Will take out front bumper and fmic to check all pipings. Any help would be nice.

[Chrischeezer]

your wastegate actuator is opening up too early

[Sleepy240]

whats your vac reading at idle? how about A/F ratios?

Also why not just circulate your BOV and see if that helps, it takes all of like 2 minutes to do, ghettoness can definetly cause problems

[bl3ujay07]

your wastegate actuator is opening up too early

It could be. I have a hks adjustable actuator and right when i installed it (before the car went into the shop), we ran it, and it was fine. When the car had problems, i adjusted it to the same length as stock. Timing is fine bc i took it in the shop today. I will try switching back to stock actuator when the car cools down.


whats your vac reading at idle? how about A/F ratios?

Also why not just circulate your BOV and see if that helps, it takes all of like 2 minutes to do, ghettoness can definetly cause problems

My vac reading at idle is between 10-12 psi. Is that ok? Also, don’t have a/f gauge yet. I don’t have it circulated because I/my brother had it welded onto the piping that connects hot pipe and intercooler outside the engine bay. I will try it later though.

Thanks for the suggestion and I’ll update this thread soon with outcome.

[bl3ujay07]

Alright, so it looks like there is no boost leak, but it sounds like it is ticking a bit under the valve cover, most likely lifters. When i took my car to the shop, i dont think he bled the lifters because it is still ticking. Either that or something with rocker arm stoppers.

Can anyone tell me if ticking lifters can affect my performance and cause the lag? maybe ras causing it? PLEASE, I really need help!!! Out of options on what to do.

[artdrifter]

hey whats goin on.....i seem to find myself having a similar problem....its weird sumtimes when i hit the gas it doesnt pick up at all.....i hear the turbo spool but no power, also my AEM wideband reads -.- nothing....now when that happens i will lift off the gas a little and it will pick up speed and read an average reading of 14 throught 15 A/F.....wtf is wrong hear? boost/exhaust leak at a specific pressure?

please gimmie sum ideas of what this could be......

hey i had this problem as well and it turned out to be my main belt. i replaced and it went away. sometimes it's the small things.

[bl3ujay07]

^^^anyone else? My belt is fairly new, as in less then 100miles. Please help me with this!!! Only thing i can think of are lifters and ras.

[bl3ujay07]

Alright, so today i switched the hks actuator back to stock one, and it is still lagging!!! I have a faze gauge and it reads about right, 7psi. Thing is, it still laggs like a N/A untill it hits 4k rpm!!!

I come to realize, that the car dont sound like it use to anymore when i installed hks step 1 264. It use to sound like a dragster or something, now its silent as a mouse!!! Could they have been installed wrong or what??? Its lagging so much more than when it was stock!!

PLEASE HELP!!! ANY SHOP IN NORCAL CAN HELP ME OUT???

[bl3ujay07]

can it be bc of knowck sensor too or no???

[jakerps13]

Put the stock cams back in.

[bl3ujay07]

^^^um...no. Had hks on there and they outperform stock. I know how they are suppose to run.

ANYONE ELSE???

[lazysk8er2]

i feel like there is still a tiny leak somewhere if you could get your hands on a smoke machine and put it through your piping that is the best way to find a leak. i had the same thing in my intercooler and it was the smallest hole ever and it made a difference.

[bl3ujay07]

did your car feel like mines (lag until 4k rpm)? I probably will go look at a fogger machine (halloween thing that makes smoke/fog).

Also, it might not be bc i dont hear my cams anymore. Even from start up.

[bl3ujay07]

So far, no good still. Tried everything. i highly doubt it being the turbo because no shaft play and no blown seals (at least i dont there is any). Now, i am norrowing it down to turbo, lifters, ras, and maybe a leak from exhaust mani.

Took car to shop and he said all vac lines hooked up and dont seem to leaking. Any help? I see similair posts, but they never update post if it is fixed. Please help, my sr running like a bicycle!!!

[pwr-adr]

Check your ic piping for leaks as well as the ic itself.
If that doesn't solve your problem disconnect your vacuum to the wastegate and see if your car gets any faster. If it picks up in power then it is a leak from your exhaust mani to the head or from the exhaust mani to your turbo. If that doesn't solve it then it is most likely something with the head. gl

[singlecamslam]

well your vac reading should be around 20 hg on stock cams. with HKS i'm not sure but i think it should be like 15? Is the car slow? or does it just not hit boost till 4k? It is a t25 after all.

[djgrasman]

hey i had this problem as well and it turned out to be my main belt. i replaced and it went away. sometimes it's the small things.

hmmm....please explain to me how it could be a belt?

just to restate what i had b4

idle A/F is on average 15 to 17 on AEM Wideband
idle is also a little rough "900rpm to 1100rpm" i would imagine bc of it being lean
while driving normal it is 14.7 to 15.8
and while full throttle it is 15 to 16.7
that is seriously lean!
and its not knocking nor pinging......please explain this retardedness.....

[TheWolf]

10-12 is low for vac.. you've got a leak or you've got a cam off a tooth.. idling rough at 900RPM with step 1 hks's... nope.. RAS can't cause the failure you're describing.. don't worry about them..

[garbury]

dude, bad timing can mess up vacuum a bunch too. I'm going with your timing is off. Check cam/chain alignment, and restab the cas according to the fsm. The timing should be right then, and you should be running fine. Use a timing light for minute adjustments.

[steve shadows]

^^^ He did my timing right when i was about to pick up the car (as in i saw him do the timing) but i'll double check. Any other suggestions. Help GREATLY appreciated.

Are you sure?

About 99% of "Specialty shops" especially when it comes to Nissans are full of shit.

I know one locally in the of industry area that is more full of shit than shit itself and is featured in magazines all the time as the TOP nissan shop

so much BS out there

I have noticed most assembly shops don't know jack shit about proper tuning and diagnosis, and most dyno shops are not the best at assembly.

For example at my location Mike does assembly and I just do tuning ..

hmmm....please explain to me how it could be a belt?

just to restate what i had b4

idle A/F is on average 15 to 17 on AEM Wideband
idle is also a little rough "900rpm to 1100rpm" i would imagine bc of it being lean
while driving normal it is 14.7 to 15.8
and while full throttle it is 15 to 16.7
that is seriously lean!
and its not knocking nor pinging......please explain this retardedness.....


You need to stop driving this thing.

I would highly suggest bringing this thing down to the shop and having me take a look at it before you break everything again

[ross.cottrill]

yeah it definately sounds like a timing issue to me.count the links to be sure!

[bl3ujay07]

well your vac reading should be around 20 hg on stock cams. with HKS i'm not sure but i think it should be like 15? Is the car slow? or does it just not hit boost till 4k? It is a t25 after all.

I’ll check my vac again, but yeah they are hks step 1. I have driven the car before this happen, and yes it is a lot slower even though it is still a t25. I believe full boost should be around 2700 or 3000 rpm. Mine just seems like it can do anything with the air the turbo is pushing in until 4k rpm. Once it hits, it seems all normal.
Plus, when shifting into gears or driving and putting into neutral, the car doesn’t die, but rpm drops all the way to zero and then it jumps up to where it should be. i.e. driving 5th gear on 45mph, clutch and put into neutral. Car rpm will drop ALL THE WAY to zero and then goes back up to where it should be. Sometimes, it even shuts off the engine in neutral, and then when you put it back into gear, engine turns back on. Hope this will help problem

hmmm....please explain to me how it could be a belt?

just to restate what i had b4

idle A/F is on average 15 to 17 on AEM Wideband
idle is also a little rough "900rpm to 1100rpm" i would imagine bc of it being lean
while driving normal it is 14.7 to 15.8
and while full throttle it is 15 to 16.7
that is seriously lean!
and its not knocking nor pinging......please explain this retardedness.....

Can you try n not get my info messed up with yours. I know we both have pretty similair problems but try and not to get it mixed up.
10-12 is low for vac.. you've got a leak or you've got a cam off a tooth.. idling rough at 900RPM with step 1 hks's... nope.. RAS can't cause the failure you're describing.. don't worry about them..

Cam tooth could be off, but I don’t know for sure. Like I said, I had shop do whole head all over. You are confusing djgrasman info and my info. Mines don’t idle rough at all. I think it SHOULD idle rougher or sound more noisy with cams bc after the first install of cams, it sounded kind of like a dragster at idle.



well your vac reading should be around 20 hg on stock cams. with HKS i'm not sure but i think it should be like 15? Is the car slow? or does it just not hit boost till 4k? It is a t25 after all.

I’ll check my vac again, but yeah they are hks step 1. I have driven the car before this happen, and yes it is a lot slower even though it is still a t25. I believe full boost should be around 2700 or 3000 rpm. Mine just seems like it can do anything with the air the turbo is pushing in until 4k rpm. Once it hits, it seems all normal.
Plus, when shifting into gears or driving and putting into neutral, the car doesn’t die, but rpm drops all the way to zero and then it jumps up to where it should be. i.e. driving 5th gear on 45mph, clutch and put into neutral. Car rpm will drop ALL THE WAY to zero and then goes back up to where it should be. Sometimes, it even shuts off the engine in neutral, and then when you put it back into gear, engine turns back on. Hope this will help problem

hmmm....please explain to me how it could be a belt?

just to restate what i had b4

idle A/F is on average 15 to 17 on AEM Wideband
idle is also a little rough "900rpm to 1100rpm" i would imagine bc of it being lean
while driving normal it is 14.7 to 15.8
and while full throttle it is 15 to 16.7
that is seriously lean!
and its not knocking nor pinging......please explain this retardedness.....

Thread jack. You are confusing others with your info and my info. NO, NO on your part.
10-12 is low for vac.. you've got a leak or you've got a cam off a tooth.. idling rough at 900RPM with step 1 hks's... nope.. RAS can't cause the failure you're describing.. don't worry about them..

Cam tooth could be off, but I don’t know for sure. Like I said, I had shop do whole head all over. You are confusing djgrasman info and my info. Mines don’t idle rough at all. I think it SHOULD idle rougher or sound less quiet with cams bc after the first install of cams, it sounded kind of like a dragster at idle.

[bl3ujay07]

dude, bad timing can mess up vacuum a bunch too. I'm going with your timing is off. Check cam/chain alignment, and restab the cas according to the fsm. The timing should be right then, and you should be running fine. Use a timing light for minute adjustments.

I took car to shop AGAIN for him to look at and he adjusted it just a tab. He said timing IS right, but I’ll try n double check myself.
About 99% of "Specialty shops" especially when it comes to Nissans are full of shit.

I know one locally in the of industry area that is more full of shit than shit itself and is featured in magazines all the time as the TOP nissan shop

so much BS out there

I have noticed most assembly shops don't know jack shit about proper tuning and diagnosis, and most dyno shops are not the best at assembly.

For example at my location Mike does assembly and I just do tuning ..

He doesn’t do dyno. He is credible, been fixing the engine for me and my brother for 3 years now and has been a Nissan Toyota mechanics for 15 years. Yeah yeah…”if he knows so much and is credible, why cant he fix it?” I honestly don’t know. He does his own builds and fixes engines from. Go ahead and bash me if you guys think not. I trust him as my mechanic.

yeah it definately sounds like a timing issue to me.count the links to be sure!

Can you inform me on this please?

[slider2828]

Man lets just stop doing multi quotes in one thread, its annoying and hard to follow....

1. Are you using a wideband to monitor your AFR?

2. Do you have a log so we can all see your AFR's

3. Did you tune your car after the cams?

4. What computer are you using?

5. What MAFS, Injectors, and Pump are you using....

[bl3ujay07]

^^^ lol. yes sir.

1. No sir, no wideband at the moment.
2. No wideband so no log.
3. Car was not tuned after cams.
4. Just a J4 ecu. repinned by my mechanic. No other electronic to tune and no boost gauge.
5. Using stock sr maf and injectors, and a walbro fp

[lazysk8er2]

what sort of gauges do you have that can provide info on the car...wideband is def needed and boost...try and find out how much vac you got at idle

[bl3ujay07]

I have a faze boost gauge (which seems pretty accurate when i switched wastgate actuator). idle is at like 10ish to 11. I'll try and get a wideband soon. Should just look for rich area.

[bl3ujay07]

Alright, after doing massive research, i checked my knock and sensor. It was loose, very loose. It came off right when i grabbed the wire. Found out there was not a cliip to hold the plug to the sensor so i made one out of paper clips. Had the starter off, so i installed it back on and started the car. Vac went to 14 instead of betwwen 10-12. Reved it a bit, and it seemed to respond better.

Then i took it out for a test drive. Still lagging a lot and i know its running rich bc it smells a lot like there is too much gasoline. So i have the negative terminal on battery disconneted for the night. Will try again tomorrow and see what happens.

Also, when checking a j4 ecu, is it the same as any other ecu, i.e. turning the diagnostic screw (???) one time counter clock wise and turn car on without starting??? Can someone help confirm this?

[singlecamslam]

yeah theres a screw at the ecu, turn it clockwise, than back again. As for your RPM dropping all the way down, that could be because of your BOV or your IACV, mine does it too. By the way i know that shop speed of sound, and i dont really trust Phil. Just my opinion though.

[bl3ujay07]

^^^ bad experience? So far, i've had good experiences with him. We've been going to him for a while so he has been giving us some hook up price. Also, sometimes he come to my house to take a look at my car too so, so far so good.

Only "bad" time is when i took my car in and he said its how a sr is suppose to run, but its not because its lagging. He doesnt know or doesnt think there is anything wrong with the car.

[djcobra]

Guy, get a tune!

you've put in decent parts in the valvetrain and still runing stock ecu, and stock turbo... Your whole damn map is way off. I suggest you don't drive the poor SR and start investing in some other parts to make full use of the cams etc... ie, Power FC, thats a start, then get a tune/dyno time.

Have you double checked your vaccum lines? are they routed correctly? Your BOV could be opening too early, there are so many factors.

And don't give me any bullshit that you don't need a tune when you install cams/valve springs/turbo/injectors bleh bleh... anyways, thats a whole different matter.

Here's a reference guide (which i found on here; search)

Quick reference of Turbo and Cams to choose.
T25...Stock, 256/256
T28...Stock, 256/256, 256/264
GT28RS....256/256, 256/264, 264/264
GT2871R .64.....256/264, 264/264
GT2871R .86.....264/264, 264/272, 272/272
GT3071R .63.....264/264, 264/272
GT30R.....264/272
GT35R.....272/272

"Im sure this will bring in some kind of debate. These are the setups i would consider though.
Lowest Cam profiles being for low end response for drifting and highest profiles being for max power for drag racing."

exactly what he said ^^^^^

good luck..

Steve.

[bl3ujay07]

^^^ i know and i want to get it tuned, but not enough money right now. hoping to get a power fc or emanagement soon so i can get it tuned.

[djgrasman]

FINALLY FIXED MY PROBLEM

sorry about posting about my similar problem on your post
but....
i finally found out that it all came down to a leaky injector!!!
damn it really gave me a headache!!!!
then i had replaced it and it all kinda.....went away...
now i have to go back and re-adjust all my sensors to run normally with all four cylinders instead of just three.

hope this helps anyone out there if they have a similar/same problem

[bl3ujay07]

did you replace all your injectors? Also, anyone in norcal willing to help? I am thinking its something to do with injectors also because it sems like my car is running really rich. either that, my knock sensor or mybe harness.

Someone near stockton, ca can help me try and figure mines out. Maybe let me switch things with them to see if it improves and see what the problem is. Just a suggestion if anyone is wiling to help. Also willing to pay a bit too.

[djgrasman]

i had replaced just one
injector number 4
or in other words the last cylinder
the reason why i only replaced one is bc i didnt have the money nor the amount of injectors to replace all of them
but listen if your car is running really rich and is being really crappy i would suggest replacing/checking and swapping injectos to see if it changes how your car runs
the reason your car could be running rich is do to the fact that injectors can get stuck open or end up going and anytime the car is on they just dump massive amounts of fuel "bad injector"
(or multiple injectors)
what is funny is that through the time i had an idle problem no one i had talked to or read up on had said n e thing about injectors to me.
this was a kind of found it out by trial and error
hope this help you out =)

[ninelives17]

hi i know i'm new here but i promise i have searched for an answer to this post, my car is doing this exact same thing, dead till 4000 rpms. does anyone know what finally fixed this guys problem?

[bl3ujay07]

^^^Mine was timing issue. Off by one tooth. make sure you take off valve cover to double check and not just with a timing gun. Hope this helps

[ninelives17]

finally fixed mine. maf was bad, not throwing any codes though. bought a/f gauge and noticed it was running lean. if anyone else has this problem you might want to check it out.

[blkkouki]

Glad to hear you got your porblem fixed. Phil swapped and did the work on my car while I was deployed to Afghanistan.. He does awesome work and he knows his shyt. I even drove my car back to Louisiana from Sacramento. We still stay in contact and he gives me suggestions and calls just to make sure the car is good. So far the car has perfromed flawlessly. Not to mention he gave me an awesome price

[Om1kron]

it's either a boost leak, it's leaking out of your bov, or you have a hole in your intercooler core.

I have the same issue. and I have a stock SR20DET Redtop, idles smooth at 1k, if I baby the car under 4 k no problems... if I get on it I get lag or hiccups on power until 4k. If I rev it drop it at 4k and make sure it stays above 4k it runs like a champ and I can smell oil.

Like a burning smell...

I'm obviously getting blowby as well.

What is your catch can set up like, are you running one? I am not. I need to have some pipes fabbed for that and am waiting on an s13/14 hybrid cover. Also I need to get new injector spacers and o-rings just to make sure it's not a fuel leak on the injector end.

I mean obviously don't know why I am asking you if you have a dude at a shop doing all of your work so us giving you advice is pointless until your mechanic figures it out.

Otherwise every tuning nut on the site will just circle jerk everyone elses theories as we have seen in the first 2 pages.

[slider2828]

If you are getting blowby at 4k, have you done a compression test? There is no way you can be pressuring the crank case that much to get blowby.... There just isn't enough presure to do that except bad rings.... definitely get it checked....

[Charsiu]

I have the similar problem, it feels like big turbo doesn't want to spool until 4000rpm
And it hit boost at 4k rpm and it boost hard, should I check my timing too?

after all my idle is a bit rough and unstable.

I just finish my swap few days ago.

[slider2828]

Check your timing....

[spooled240]

cam timing will greatly affect turbo spool. When I dropped my ka-t in my exhaust cam was a tooth advances and I spooled 5 psi in nuetral lmao

[240sx-pat]

Guys I got a quick question my SR seems to be lacking power. I'm think it's because I've got a leak somewhere and the main place right now is from the downpipe to the testpipe I can feel air coming from it when it put my hand near it.


Could this be the cause of my slow ass SR? I mean my boost gage is showing that it's at 7lbs however I'm not feeling shit.

[cotbu]

Guys I got a quick question my SR seems to be lacking power. I'm think it's because I've got a leak somewhere and the main place right now is from the downpipe to the testpipe I can feel air coming from it when it put my hand near it.


Could this be the cause of my slow ass SR? I mean my boost gage is showing that it's at 7lbs however I'm not feeling shit.

Fix it, but No! Your sr is slow for other reasons! The test pipe and down pipe are after the turbo, so why would you think a leak there has anything to do with why your sr is "slow"! Just FYI 7psi ain't shit and people claiming 205hp while pushing it from the t25 are stupid. push 11psi and see if, you still feel the same way!

[patsS14]

check your cam angle sensor

[idahotuner]

yeah sounds like your a tooth of on one of your cams, i have 264 cams on my car and it idles smooth at 900 rpm with 96# injectors,

pull your valve cover off,
and check cam timing to crank,
and then reset cas, - make sure your not 180 degrees off
make boost tester,
use an air compressor, and pressurize your whole intercooler system through the turbo and listen for leaks, they will be obvious, i have a buddy watch my boost gauge and i pressurize mine up to 30 psi.

[e5s4y]

hey whats goin on.....i seem to find myself having a similar problem....its weird sumtimes when i hit the gas it doesnt pick up at all.....i hear the turbo spool but no power, also my AEM wideband reads -.- nothing....now when that happens i will lift off the gas a little and it will pick up speed and read an average reading of 14 throught 15 A/F.....wtf is wrong hear? boost/exhaust leak at a specific pressure?

please gimmie sum ideas of what this could be......

this is how mine feels sometimes too. boost gauge reads full boost, but then at 4k-ish, its like a kick in the ass. wideband shows everything good tho. the lifting the pedal a little does increase the acceleration too. still good enough to go sliding around tho, haha
s15 spec-r- t28

[idahotuner]

IDAHOTUNERS SR FIRST START UP - YouTube (http://www.youtube.com/watch?v=mQA-2j3pmg8)

this is how it will sound with your cams off a tooth while idling, vacuum will be less then normal, it close enough to idle, and rev up just slower, i never even attempted to drive it when it sounded like this, i new something was wrong and double checked everything,
here is once i fixed it
Idahotuner SR start up RUNNING GREAT - YouTube (http://www.youtube.com/watch?v=Z-xKF4xS_iM) notice the sound difference, doesn't sound like a big cammed car any more

[idahotuner]

so cam timing

[ghoti]

Just posting for future reference but when you guys say Cam Timing it's when you replace the cams?
To my understanding when being a tooth off on the CAS your car won't start.

[idahotuner]

your car will start a tooth off on the cas just take some work lol, but when we say came timing we are talking about intake cam to exhaust cam to crank timing

[tom_sr20]

if timing is good. how are your ignition coils? mine had this same stumbling problem for years that ive owed my sr. fixed when i changed out all four ignition coils. might want to check yours for cracks. mine didnt have any cracks but since i was willing to take the chance of fixin the problem i bought four new oem coils. it does have 100k plus miles on them too so i think it was about time. fixed my problem made it feel stronger as well. hope this helps

[Jrc36]

What's going on I have the same problem on my S14 Notch Top , after 4k rpms it bugs out when I try go give it more gass , I was told that it's the Maf , can that be true if i have the wrong Maf ?

[koukimonst3r]

What's going on I have the same problem on my S14 Notch Top , after 4k rpms it bugs out when I try go give it more gass , I was told that it's the Maf , can that be true if i have the wrong Maf ?


Do you know which one you have?


52F00 is S14 Zenki SR20DE
52F01 is S14 Kouki SR20DE
69F00 is S14 Zenki SR20DET
69F01 is S14 Kouki SR20DET / S15 SR20DET

[Jrc36]

Do you know which one you have?


52F00 is S14 Zenki SR20DE
52F01 is S14 Kouki SR20DE
69F00 is S14 Zenki SR20DET
69F01 is S14 Kouki SR20DET / S15 SR20DET

I have a 69F01 AFH50 - 18A

[Abeo]

Bump from the dead. I had this problem for the longest time, and this was one of the threads that kept coming up when I searched.

My car was slow to spoil, had weird timing retarding in boost, and had sluggish throttle response even at idle. Turns out it was the PCV valve making a huge boost leak that was being dumped into the intake pipe after the maf across the valve cover. Since the air was metered, it didn't show the typical symptoms. The PCV rattled and I couldn't blow through it ... Blocking it off while testing something else identified it.

Just wanted to add my solution after chasing this problem for a long while.

Edit: Turned out my car had a bad CAS also. Had timing scatter that was really bad after 4500 rpm, identified by a timing light while revving it up (it would jump from ~15 degrees to ~40 for an instant). The car was on the dyno and had a up and down torque curve showing the engine knocking, going on the knock map, then off, then knocking again...

[Tulok]

I had similar symptoms chased them for months. Turns out that the block and head had been shaved during rebuilds.

Solution was get adjustable cam gears and degree them so the intake began to open at about 8* btdc. Moved spool down at least 1500rpm. Would spin in 3rd where before it could barely boost in 1st. Open waste gate t25 on race gas