N/A highcams in turbo

[CcL]

My mechanic is advising me to use back my original turbo cam. currently i'm using a cam for N/A with higher duration and overlap. the stats are:

LIFT (in): int=0.471 exh=N/A
Duration (deg): int=270 exh=257
Opening (deg): int=N/A exh=N/A
Overlap (deg): 38

its paired with an adjustable cam gear at 2degrees advance.
what will have using a N/A cam in a turbo??

My original turbo cam stats are:

LIFT (in): int=0.391 exh=N/A
Duration (deg): int=225 exh=218
Opening (deg): int=4 BTDC exh=39 BBDC
Overlap (deg): 3

what are your advice to me?? I'm currently doing 0.9bar boost without pinging. high cams with the adj. cam gear at 2degrees advance. and my ignition timing is at 18deg advance. at 0.95bar to 1bar boost it will start pinging. if my ignition timing is advanced at 15deg i can boost 1.1bar no problem. but i'll be crawling out of junctions... :lol:

Is it OK to retain my N/A high cams and get a piggyback to reprogram how everything runs?

Please advice... really luin sui lahhhhhh :ph34r:
thank you yah all sifus ;)

 

[acbc]

I think u r the only Volvo sifu around... *respect* :P

 

[CcL]

aiya dun need volvo sifu one lahhhhh
imagine u take a 4g93p high cam and place in a 4g93t
what happens??
same concept i think!

 

[GSR5559]

if im not mistaken there is one dude in here, driving 1.8 NA lastime den convert into GSR, he uses back the high cam dat has been regrind by matspeed..and he got J5 to tune evrythin..so i think NA cams can be fitted into Turbo if u have good settings and tuners..
jus my 2 rupee

 

[Joeker]

I don think the cams nor the timing advance in valve train and ingition are the cause of your problems.

In fact, there is no problem in the first place.

Its only a matter of the amount of mods you've done to your engine which has caused confusion to your engine's brain.

Its like I'm asking my mom why I can no longer fit into the jeans that I had when I was 13. THe answers is simple, I've out grown the size of that jeans.

Now lets see, if memory serves me well, you're runing a bigger Turbo,
bigger Intercooler, higher boost, uprated fuel pump and now longer lift cams.

The only thing mising here is management.

 

[splolo]

Originally posted by GSR5559@Sep 7 2004, 08:30 PM
if im not mistaken there is one dude in here, driving 1.8 NA lastime den convert into GSR, he uses back the high cam dat has been regrind by matspeed..and he got J5 to tune evrythin..so i think NA cams can be fitted into Turbo if u have good settings and tuners..
jus my 2 rupee

Eh u talkin abt me ar? :D

 

[GSR5559]

splolo : nopes..it is fairuz ,one of zth member..
he uses NA highcams from his previous engine into his turbo engine ..
and no probs indeed i guess

 

[xin]

can we use GSR cams on a 4G93p head then ?

got forumer said tat this torque is constant after doing such ?

i m in the decision of replacing GSR cams or 4G92nonmivec cams into my 4G93p head ...advise pls

 

[khoyos]

dunno about volvo. but in my case, i've tried to rojak a number of cams to my engine. mitsu 4G61T. these are my findings when i tried 4G63 NA dohc cams. 1. exhaust cam only: less boost drop when shifting gear, slightly better power. 2. intake and exhaust cam: cant feel any g-force at all, feel like no power at all. turbo struggle to wake up, lag teruk, and bla bla bla. but all cams i tried were OE cams. no aftermarket ones, cant afford. mitsu cam rojak might not yield same results for volvo...

 

[140dB]

na vs turbo cams

Hi there,

I have read the 4g9series manual from mitsu and have seen the spec for 93 and 93t cams. Also, someone posted the spec for 4g63 and 4g63t before with the same results:

they posess the same duration but "no" overlap. meaning, on paper it shows the exhaust cams closing and intake cams opening at same angle.

my own reasoning for this:

1>na cars use cam overlap to produce more power.

2> turbo already forces airfuel into the chamber. any overlap might cause high pressure airfuelmix from intake to force its way out straight the exhaust cams(fixed anti lag?hehe)

the end result may be high fuel consumption.

my2c
140dB

 

[Joeker]

Cam Overlap is to promote scavenging and reduce emissions.

AFAIK, all modern engines have overlapped cam durations.

 

[xin]

its a matter of the duration of the overlap period..

 

[akonana99090]

wif my logical thinking...
i think it is very interesting to have a try...
maybe will decrease ur turbo lag wif hi-cam...
cause it caused more air to enter when u still boost off...
but maybe u need to increase the size a bit bigger of ur turbo exhaust...
because when the vavle overlap may caused the turbo blow in for nth...
it will come out from the exhaust valve to create back pressure....
correct me if i'm wrong...

 

[140dB]

having said all that in my last post, i have been running an aftermarket cam in my bot setup and made good power. 150engine hp for 12V, 1.3 litres. also, a lot of honda turbo users are running thier na vtec cams for up to 500hp...i guess wif a twin cam setup, there is still room for some adjustment...

 

[skyline_maniac]

hmmm interesting topic.....so the same concept goes to hybrid of mivec turbo as well rite? since mivec cams is 300 degrees.....

so meaning regardless of tuning....the end result will still be having high FC?

 

[140dB]

high overlap on a turbo will also reduce chances of detonation

high fc is not an engine blowing problem. its the a/f fuel ratio reading may be 'tainted' while tuning....