JRSC Only hitting 7psi with 3.2 pulley Kpro Tuning

beppe786

Beppe
Messages
2,062
im using 650cc injectors on the standard fuel rail. i read somewhere on a jrsc might get fuel starvation..

is upgrading rail gonna be worth it noticeable gain? and which is the best one to go with?


plus only hitting 7.5psi with the 3.2in pulley should be more.. anyone know what can be the wrong

Got a new belt and Gruppe m intake, no belt slip and its getting enough air


thanks in advance
 

dave c

400hp K20
Messages
2,501
beppe786 said:
im using 650cc injectors on the standard fuel rail. i read somewhere on a jrsc might get fuel starvation..

is upgrading rail gonna be worth it noticeable gain? and which is the best one to go with?


plus only hitting 7.5psi with the 3.2in pulley should be more.. anyone know what can be the wrong

Got a new belt and Gruppe m intake, no belt slip and its getting enough air


thanks in advance
Don't know the answers to the SC boost questions but in regards to the fuel rail, standard is suffice.

If you're getting starvation you want to increase your flow to the injectors by adding either an inline fuel pump or replace with a larger fuel pump and then if there is still insifficent fuel you will need to upgrade your injector size.

I'm using ID1000's as reference
 

beppe786

Beppe
Messages
2,062
i might get the injectors flow tested/ cleaned

car runs fine cant seem to tell if i have fuel starvation no hesitation, just was thinking its linked to the low psi

thanks Dave.. you gonna be a japshow next week?
 

beppe786

Beppe
Messages
2,062
pudski said:
If you were getting fuel starvation you would be leaning out, but your datalogs are fine.
Great so no fuel issue then

anyone shed any light on the low psi?
 

dave c

400hp K20
Messages
2,501
nah off to silverstone to watch touring cars.

Boost leak, all hoses clamped down mega tight?
 

jdmsteve

Advanced Member
Messages
483
Are you using a brand new charger. Could just be slight wear in the screws or seals somewhere.

But as Dave says check all the above also
 

jdmsteve

Advanced Member
Messages
483
You know what, thinking about it the low pressure could be down to your exhaust setup. The more restrictive the exhaust the more pressure you'll see. So larger exhaust would result in a lower pressure but it won't go any slower.

If it pulls like a train I wouldn't worry too much about it.

I know when mine was mapped by romain he also said I was only making about 6.5psi instead of 7

Still goes like the clappers mind 👍
 

beppe786

Beppe
Messages
2,062
jdmsteve said:
You know what, thinking about it the low pressure could be down to your exhaust setup. The more restrictive the exhaust the more pressure you'll see. So larger exhaust would result in a lower pressure but it won't go any slower.

If it pulls like a train I wouldn't worry too much about it.

I know when mine was mapped by romain he also said I was only making about 6.5psi instead of 7

Still goes like the clappers mind
its quick.. find out next week how quick it does a 1/4 mile at japhow

what size pulley you using? how much did it make on eurospec dyno at the wheels?

ill check all lines tonight
 

leejw87

Spoon Whore
Messages
1,523
I get a fuel cut in mine when my fuel is under a quarter of a tank, i think a larger in tank fuel pump is required.

low boost reading can be caused by belt tension (can slip slightly without you even realising it) also cam angles & exhaust setup will dictate overall pressure.

When mine was first mapped it was only producing 5psi as my belt wasnt fully tensioned but didnt show any slip when mapping
 

raz786

Advanced Member
Messages
1,887
It is likely to be the belt slipping as lee mentioned, remember romain mentioning some sort of adhesive or spray to get the belt gripping properly, maybe worth looking into.
 

beppe786

Beppe
Messages
2,062
im sure its not belt slip as this is a brand new belt and ive gone down a size just so its extra tight.. i found a lose vacuum pipe large one that goes near the Jackson spout gonna tighten that up and see..

just could be that the exhaust flow is so good that's why not hitting high psi..

keep you posted thanks for the advice
 

jcdc5

Advanced Member
Messages
244
I'm on 9.5 psi ATM with larger crank pulley, I have changed to auto tensioner and it has been spot on!
 

beppe786

Beppe
Messages
2,062
like lee said it could be cam angles in the mapping.. if in high cam your map is set near 50 degrees then it wont build up psi than if your map is set to 35 cam angle then psi will build up will be more.

I think thats the logic behind it.. if im wrong please anyone with more knowledge of mapping correct me.
 

beppe786

Beppe
Messages
2,062
good info


Doug briefly talked about extreme cams. There are no really wild cams for the K-Series yet, but there are experimental ones that Hondata checked out. Add lots of timing at low end for impressive torque gains, raise idle speed, reduce overlap in part throttle.

Supercharged engines:
- Tuning is really similar to NA larger motor.
- Supercharged engines love overlap (high cam advance)
- High cam set to 50 degrees throughout most of rev range, then down to 40 from 7000 rpm on up
- Low cam VTC 45-50 degrees
- Cam angle actually affects boost in manifold
- Set maximum closed loop to 110kPa (over that the ECU will ask for open loop).
- The higher the RPM, the higher the boost. (Greddy turbo actually got less boost at higher RPM)
- In the fuel tables, boost curves should be very flat and smooth
- However, more boost does not necessarily mean more power
- Ideal A/F ratio at WOT under full throttle is lower than NA, 11.5-12.5
- Street version of the JRSC had 212-220 whp, went up to around 250 with Hondata.
- Interesting note: They fit a JRSC to a base! Cables on throttle body are reversed on base. They turned the whole thing around. Not sure if it is just a technology demonstration or will become a real product.
- Use variable VTEC window like on stock engine but with two exceptions: you can set the lower boundary lower, down to 3,000, but set both the lower and higher point to occur at full engine load pressure. That way there won‘t be a linear line. Under load it goes into VTEC, under part load it goes out of VTEC once revs fall below the upper boundary.

full web page here : http://www.pencomputing.com/rsx/HondataSeminar.html
 

beppe786

Beppe
Messages
2,062
all new silicone pipes and clamps plus tighten the intake bolts and now hitting 8 psi :xgrin:
 
Top