Problems K20a turbo

type-r · Post by **type-r** » Sat Mar 14, 2009 10:23 am

Hi,
I have a k20a (JDM k20) which i fitted a turbo, which i am boosting only 5 psi. Please note that i am using normal pump gas(but it is not that good as USA regular pump gas).
Mods that i made are:

Peakboost sidewinder turbo kit
wastegate 44m (5psi)
GT35R AR 70
K-Pro
Hondata 4-bar Map Sensor
RC 750cc injectors
Walbro Fuel pump 255 lph
3" exhaust

The problem is that sometimes it works well and boost comes in and i rev it up till something like 8,000rpm , but sometimes it stops on 6,000 rpm (like a rev limiter). I have lean protection on, but i dont think its lean because there is a lot of petrol spots to the back of the car(since the car is white it is more noticeable). What do you think is happening? i am confused since sometimes it works well and sometime it does not. If someone can help pls!

cranny · Post by **cranny** » Sat Mar 14, 2009 9:22 pm

you need to post a datalog too buddy. get the car in 3r gear at 2k rpm. floor it , and dont let off till redline.

type-r · Post by **type-r** » Sun Mar 15, 2009 3:32 am

The problem is that it does not go to redline. It stops till 5,000rpm or 6,00rpm. That's the only problem that i have. Boost comes at 3,500rpm. And till 5,000rpm it feels strong and then it cuts. I will try to make a datalog today. But i am thinking that it needs more fuel. Because when i went around with the laptop with me seeing where it stops, it stops on the 11th and 12th column at 5,000 or 5,500 rpm.
Thanks for the help

bdw another question. Cranny are you a tuner or something like that because always i see your posts when people have problem.

cranny · Post by **cranny** » Sun Mar 15, 2009 10:51 am

if you want help , post up a datalog , looks to me your most likely hitting lean protection. maybe overboost idk without a datalog.

define tuner? can i tune a car? yes. do i do it for a living? no.

you always se my posts cause im a true car enthusiast to the core and i like to help people who need it. simple.

fonz600 · Post by **fonz600** » Sun Mar 15, 2009 12:12 pm

Your crossover is set to 5600. Does it stop b4 then?

I'm only theorising here, and cranny may pipe in whenever he feels like it as turbo's ain't something I'm experienced with, but although you are running 5PSI it is probably possible that you could still hit boost cut. A log would help though.

5PSI with 6PSI Boost cut.
Your car is spooling at 3500 you say and crossover isn't till 5600.
Your running a quite conserved cam angle of 30 degrees which with the 5600 crossover has a possibility of building boost beyond 5PSI.
Or something along those lines. Hard to explain what I mean.

If it was me I'd try a couple things like locking the cam to 50 or slightly lowering the crossover to see what happens.

cranny · Post by **cranny** » Sun Mar 15, 2009 4:54 pm

its too much for his setup fonz. his cam doesnt ever have to go above 30 the whole map. this is of course my opinion. the 5600 crossover is probably pretty close to being good. unlike NA fonz , turbo cars seem to stretch the efficiency of the low cam out alot further than NA. he needs to post a datalog , lol.

type-r · Post by **type-r** » Mon Mar 16, 2009 2:42 am

i will go for a ride today and i will post a datalog. Thanks for the interest shown. Bdw why do you think it is boost cut? i have a 5psi spring in the wastegate, it can never boost more than 5 psi i think.

type-r · Post by **type-r** » Mon Mar 16, 2009 7:19 am

i went for a ride and i had 3 datalogs. I think Fonz is right, because engine cuts when boost is at 6psi. I dont know why it is happening because i have a tial wastegate 44mm and on the box it says something like spring 5psi. Please see the datalogs and tell me what do you think? i don't think its lean btw. give me suggestions please. Thanks to cranny and fonz

fonz600 · Post by **fonz600** » Mon Mar 16, 2009 2:18 pm

Your definitely experiencing boost cut. Your hitting 6PSI then getting the fuel cut.

Looking at other calibrations all of them have Hot Boost Cut set to 10PSI and all but 1 have Cold Boost Cut set to 10PSI.

I'd recommend speaking to cranny though mate as all my experience is on Supercharged and N/A.

type-r · Post by **type-r** » Mon Mar 16, 2009 2:41 pm

Fuel Cut??? Do the boost cut protection make a fuel cut also or not?? Thanks for the help fonz. The problem is that i have a 44mm wastegate and on the box there was that it is a 0.3bar spring. I thought that i might need no boost controller since boost more than .3 bar will end outside. But it wasn't the case. Any help appreciated

cranny · Post by **cranny** » Mon Mar 16, 2009 2:59 pm

here , load this onto your Kpro and try doing another 3rd gear pull buddy. the reason your car is boosting more than the spring is your manifold. peakboost manifolds creep a little , but i dont think youl boost as high as 10psi , well see , lol.

type-r · Post by **type-r** » Mon Mar 16, 2009 11:15 pm

cranny my problem is i cant go past 7 psi, or it will go all into pieces. I have a high compression since i am using a stock k20a (11.7:1 compression). I am using normal pump gas since here in malta there is no high octane available from the petrol station. I dont think normal pump gas would do for my compression and that boost. I will be making a boost controller and set it to 5psi and i will see from there because i am not relying on the wastegate. It has a .3 bar spring, so i think that it must throw out all the bost more than 5psi? Do you think that with a boost controller, i can solve my problem? What do you think of the fuel tables? will it run lean?
Thanks cranny i appreciate your help

fonz600 · Post by **fonz600** » Tue Mar 17, 2009 8:35 am

type-r wrote:cranny my problem is i cant go past 7 psi, or it will go all into pieces. I have a high compression since i am using a stock k20a (11.7:1 compression). I am using normal pump gas since here in malta there is no high octane available from the petrol station. I dont think normal pump gas would do for my compression and that boost. I will be making a boost controller and set it to 5psi and i will see from there because i am not relying on the wastegate. It has a .3 bar spring, so i think that it must throw out all the bost more than 5psi? Do you think that with a boost controller, i can solve my problem? What do you think of the fuel tables? will it run lean?
Thanks cranny i appreciate your help

You sure it's 11.7:1? What engine is your car for?
JDM K20A that is in JDM EP3 and DC5 is 11.5:1

type-r · Post by **type-r** » Tue Mar 17, 2009 9:06 am

I thought it was 11.7:1. But either way the boost that can handle stock pistons with European regular gas is 7psi. I didn't want to boost 7psi. Can anyone tell me if i have a wastegate with a .3bar (4.5 psi) spring, can i make a boost controller to set to like 5psi? Because the spring is not opening the wastegate at 5psi.

any help appreciated

cranny · Post by **cranny** » Tue Mar 17, 2009 1:36 pm

i already told you , peakboost manifolds creep a bit. worse in low boost. a boost controller cant run lower boost , only higher. the lowest boost you can run is whatever your wastegate will allow with a straight vacuum line to it. what octane fuel do you have available? if you can get 91 pump gas , you can run 10 psi.