as the title says -

 

i know 14psi is the maximum that you should run an engine which doesnt have forged pistons.

 

I would like to hear from anyone who is consistently running more that 14psi on a relatively standard engine.

 

I was thinking about running 16psi - but i just dont know whether to risk it.

 

Regards,

 

Alex

Originally posted by lymon

The stock engine and pistons are very strong.

It can take up to 575-600rwhp as long as everything is running right.

The biggest reason the pistons fail earlier is because of detonation or severe overheating.

Forged pistons can withstand detonation a lot better.

 

Personally I'd upgrade the injectors before even thinking about upgrading the turbos.

The stock 370cc injectors are already at their max with stock turbos running 16-17 psi.

The injectors just can't flow enough fuel and max out at around 370rwhp.

 

-Eric

 

Hi Lymon,

 

thats seems a lot of horsepower to me and a lot more than i have been lead to expect, however i know your opinion is respected on the forum so i would be grateful if you could clarify in your opinion what my engine could run safely.

 

i am currently running t25/28 hybrid roller breaing turbos, HKS intercoolers, HKS superdragger exhaust, SE exhaust downpipes, Fidanza aluminium flywheel, SE vernier pulleys set at 5' intake advance and 15' exhaust advance and greddy profec e-01 and emanage system.

 

does you original post suggest that if i upgrade to 555 injectors I will be able to run a level of boost? If so where would you estimate the safe limit to be?

 

Thanks for your help.

 

Kindest Regards,

 

Alex

Alex, in my opinion it is essential to upgrade the intake and exhaust, the injectors (to 555cc or 740cc), intercoolers and engine cooling system (larger oil cooler and radiator), before upgrading the turbos.

 

the compressed air that comes out of a larger then stock turbo pushing 14 PSI is quite a lot denser (cooler), which means it makes more power at the same amount of boost.

This means also that if you are running the stock injectors with larger turbos, they'll max out earlier.

 

I frequently run a boost that peaks to 21 psi on a stock engine/headgasket myself...I've been told from several sources that the stock headgasket can take up to 24-25psi

 

-Eric

HI Eric,

 

thanks for the response - i think that has cleared my mind a bit - definitely time for some 555 injectors.

 

I am running with a custom alu radiator but i am unconvinced about its performance.

 

i think i'll fit 555 injectors and run it at 18psi for a while and she how she goes from there.

 

Kindest Regards,

 

alex

Im getting worried. I've had my car chipped, tt manual and on the aftermarket boost gauge that is fitted it's reading 1.3 bar, or as the guy who chipped it said about 17psi. I believe that my car had had a lot of stuff done to it when it was in Japan, boost upgrade and traction control, but for some reason it had all been taken off when it was imported. Am I running the risk of blowing my engine. It is bl**dy fast and will spin the rear wheels pretty much no matter what as soon as it hit's the 1.3 mark. ???

well cc300zx 1.3 bar is more like 19 psi so be very careful because your running far too much for stock internals/injectors i would get it taken down if i was you, do you really want a rebuild...like me:cry:

 

Kirbz

CJ you just missed out on group buy on Nismo 555's :( can get you more though, let me know when your ready :)

hi chris,

 

i was just going to get SE to fit some - but how much for nismo's ??

 

Regards,

 

Alex

Ok, now I am worried. Also my car is making a strange noise. Since having it chipped I have noticed that sometimes when I change from third to fourth as I lift the clutch pedal it makes a strange grinding noise for a split second. Also today as I was parking and manouvering the car in first gear it made a grinding or scraping noise again??? As a driver I don't drive everywhere fast, in fact I only ever use the speed for overtaking. My normal journeys are to and from work at two thousand revs doing sixty miles an hour. The only time I would use the power is in short bursts for overtaking, if I only use it like this would it be ok??? In your opinion??

dont know what the grinding is maybe clutch or gearbox but all i would say is when you do press the pedal on the right listed for detting, as it will destroy your engine!!

 

Kirbz

Cheers, I think i'll have a word with the company who chipped it as they assured me although it was above average it would be fine. I'll get them to look at my clutch at the same time.

CJ you got PM

Darn!:( I was hoping you were going to post the price of the 555's Chris...been wondering if my budget could stretch to 'em this side of Xmas...;):D

 

Leigh.

Originally posted by Chris@GetGReddy

CJ you got PM

 

not yet i havent :(

 

try alex@wheeler.biz

By the way, been trying to get on your website this afternoon Chris but it won't connect...probably just me and my naff computer but I thought I'd mention it just in case!:)

If you both went for them could do a mini group buy at £625 a set :)

Originally posted by friday

By the way, been trying to get on your website this afternoon Chris but it won't connect...probably just me and my naff computer but I thought I'd mention it just in case!:)

 

Oh yeh its down :confused: thanks for letting me know. If you ever see it down please post a message in my section as i dont check the site every day :)

hi chris - how quick can you get them??

 

Regards,

 

alex

CJ they will take around 10 days maximum maybe 7 :)

Originally posted by kirbz

when you do press the pedal on the right listed for detting, as it will destroy your engine!!

Unfortunately you can't hear detonation (knock) until it reaches such a high amount that the engine is virtually dieing in front of you. The advantage of Pocket logger or TMO is that it uses the GTO knock sensor to read this, and even at small levels you can see the results, and back the boost off. I believe the Zeds have a knock sensor built in aswell?

 

Might be worth asking the PocketLogger guys if they do a version that will run on your cars. I'm sure if the market appeared they would do the programming.

 

I also have a product from PocketLogger called a knockbox which I'm fitting in a couple of weeks. This also reads the sensor output along with the exhaust O2 reading and displays it on the dash. Again, I don't know if they do a version which will work on the Zeds.

 

Steve

On a Zed it's not possible to monitor the detonation sensor directly.

A disadvantage of the Zed's detonation detection system is that it will only listen to the detonation sensor up to 3500 RPM, probably the signal will become to noisy on any higher RPM's.

 

There are aftermarket knock detectors available..I think HKS or Techtom has one, but I'm not sure if these are any good.

 

If you have a conzult/consult you can see when the ECU detects knock, because it will initially retard the timing by a degree, until it has reached a certain limit and then it will switch the wastegate solenoids and will go into safety mode (safety boost)

 

A better way is to monitor A/F ratios with a wideband O2 sensor or by monitoring the exhaust gas temperatures (by using EGT's).

By monitoring these you can PREVENT detonation..

 

-Eric

chris - is that 625 inc vat ?

 

Regards,

 

alex