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Head gasket & boost & camshafts (RB25DET ECR33)

Vovan

By Vovan,
in Engines & Forced Induction

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Vovan Enthusiast

Vovan

Posted
Posted

Hi everyone from Russia :D couldn't find any info on the following topics here (Russia), so decided to ask you ;)

i ordered HKS Head gasket 1.6mm - are there any difficulties to install it? or i can just replace it and increase boost and fuel?

what are the best A/F ratio for 8.6 Compresion level? and what is the maximum boost that it can handel?

Will RB26DETT camshafts fit into RB25DET?

I'm also looking for close ratio gearbox - but cannot find anything.. only for RB26DETT and at about $5k cost :(

are there any substitudes for this?

thanks!

meggala Grand Master

meggala

Posted
Posted

close ratio gear boxes start @ 5k

with the head gasket 1.4 bar should be ok jsut watch out for detonation as for a/f ratio's aim dfor 11.8-12 to 1 to be safe you will make more power going leaner but this is safe

rb26 camshaft will fit but you will ahve to convert from hydrolic lifters to solid to run them adn you would loose your vvt.

my site has head torqing specs on the parts and info page

cheers

meggala

btw great english

Vovan Enthusiast

Vovan

Posted
  • Author
Posted

to say the truth, i didn't understand anything what is written about head torqing specs :( what's that?

what if i get HKS camshafts IN and EX lifting 8.8 and 9.0 - will i have to get rid of NVCS system?

i also order S-AFC II, do you have any maps for it already? or i should configure it specially for my engine trying to be in 11.8-12 to 1 a/f ratio?

btw, right now my boost is about 0.5 - 0.6 (max), if i make it higher there is some kind of blows out of muffler and engine stops to rev for short period of time (milliseconds), and that affects the acceleration.. i thought that there are some kind of fuel limiter and order fuel cut defenecer - will this help to solve the problem?

also, will the standart turbo give boost at about 1.0-1.2 bar?

benm Grand Master

benm

Posted
Posted
Originally posted by S14Drift!

Everyone say that the max boost for stock turbo is ~ 15 psi or ~1 Bar ..after that your pushing too much for the ceramic turbo wheel...and it will destroy itself!

Not sure where u read that? Most people from what I have read say that 12psi is the most a stock RB25DET Turbo should push. I wouldn't be all that game to try anything higher really.

dojobi Experienced

dojobi

Posted
Posted

benm, I'm running 14.7 psi and it probably spikes a little higher than that at the moment. No problems at all (so far... :P)

I do have a series 1, though, and the general consensus is that they can take a little more boost than your series 2 R33.

benm Grand Master

benm

Posted
Posted

I have a '95 S1 R33.

Im abit scared of the whole 'boost' thing.

To me the higher the number = the higher the danger which is probably why i drive around on 7psi all day everyday :P

On 12psi im leaning out so no point in winding it up any higher. How long have u been running 14.7psi for? Also how long do you run it on full boost for?

I wonder what gains i'd get and how long the turbo would last.. (provided th rest of my car is working fine.

dojobi Experienced

dojobi

Posted
Posted

Well it's been that way for over 6 months now and I do give it a little bit every day. I've also done a fair few 1/4 runs at my private dragstrip. It felt stronger than 12 psi, so I left it there).

Also, I'm not really a big believer in high/low boost switchable setups, cos I like the idea of having the car run exactly as it was on the dyno. So that's why I only run 1 Bar. That said, I've seen a unichip setup where the guy had different maps for high and low boost and also for shit petrol. It was really good. I almost bought one when I saw it.

My car was nowhere near leaning out when I upped the boost. In fact, before I got my SAFC I had A/F ratios in the 9s! Then again, you have probably got one of these magical 95 ECUs.

benm Grand Master

benm

Posted
Posted

I believe I do have 1 of the magical ECU's coz I currently dont have any aftermarket management of anything.

The only time I use 12psi is for Dyno runs, Trackdays and eventually 1/4's.

Guest INASNT

Guest INASNT

Posted
Posted

please dont make this another thread about what the max psi u can run the stock turbo at!! We have had a million of em already, if u r game run it higher and higher and then when it blows u will know the limits!!

Vovan

As the the hks 1.6mm head gasket, thats a good buy, but u should get some cams and head work done if u r gonna replace the head as u will have all of it out anyway.

JimX Grand Master

JimX

Posted
Posted
Originally posted by Vovan

i also order S-AFC II, do you have any maps for it already? or i should configure it specially for my engine trying to be in 11.8-12 to 1 a/f ratio?

The S-AFC doesn't come with any settings pre-set. You may be able to apply someone else's map if they have a similar engine setup to you, or do it on the street yourself, but the best way will be to do it on a dyno with the proper AFR monitoring.

Vovan Enthusiast

Vovan

Posted
  • Author
Posted

the problem is that we don't have any dynos here :D(( first i ordered camshafts but then decided to cancel that order cause no one will be able to configure them properly here :D shit country :)

Do you guys have any tips how to configure S-AFC without any hardware... it won't show A/F ratio, will it? :( how can i know if the mixture is rich or not?

now i'm thinking i should by PowerFC instead of S-AFC and AVC-R and all the limiter's removers... :)

BTW, is it possible to remove the rev limit and move it, let say, to 8k instead of 7k? will it help? i didn't find any info on that here in the forum.

Guest INASNT

Guest INASNT

Posted
Posted
Originally posted by Vovan

the problem is that we don't have any dynos here :D(( first i ordered camshafts but then decided to cancel that order cause no one will be able to configure them properly here :D shit country :)

Do you guys have any tips how to configure S-AFC without any hardware... it won't show A/F ratio, will it? :( how can i know if the mixture is rich or not?  

now i'm thinking i should by PowerFC instead of S-AFC and AVC-R and all the limiter's removers... :)

BTW, is it possible to remove the rev limit and move it, let say, to 8k instead of 7k? will it help? i didn't find any info on that here in the forum.

there has 2 be a dyno somewhere there!!

u wont know what a/f ratios u r running unless u get an oxygen sensor of some kind and place it at the end of your exhaust.

u can move the redline to 8k with a pfc

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