Hey guys, I have some question about NA tuning our cars. If I get the cam shafts, pistons, and with high lift valve springs. Am I going to be safe with high RPM? How high can it go? Don't I need to do something with the ECU? If so, then isnt it just painful cause ECU is just too much pain... to deal with.

Also, I'm so confused about running in "high compression ratio". What it really does and how would it affect our engine?

Thanks guys.

 

What year is your Z?

 

If you want to go for higher RPM, firstly.... how high do you want to go up to... if you are looking at no higher than 7200rpm, then you need to replace those rod bolts (proven by Nismo) to keep the reliability of hitting that rpm, it also means that the bottom end will need to be off and you might as well change the rods to a lighter and stronger item (don't know if it is available yet for N/A application besides Tomei rods from Japan)... and that should take you up to 7500 without a problem... if you want more, you might need to replace the crank though to reach up to 8000rpm. 2ndly, you will need to have the cams that can still give out a lot of HP at that higher rpm...

Piston wise, if you want to go for higher compression ratio, then you will need to get the pistons replaced or even the heads (nismo heads)... but I heard that higher compression ratio engine is harder to tune and have more reliability issue than the turbo setup since you are running at the constant high compression...

I might be wrong, but that's just my knowledge so far on the rev limiter of the engine from what I read on the boards...

cheers,

richie

 

^_^ thanks for the info. My car is a 2003.
Another question. What gives NA tune more hp? Does raising up RPM produce some horsepower? Raising the compression ratio raise some horsepower too?
I think Honda's S2000 and Mazda's RX-8 are really impressive... >_< 9000 RPM redline. Now thats nice ^___^

 

Raising up your rpm will not give you any HP... this also depends on where your power starts to drop at which rpm... you will not GAIN more HP by raising the RPM unless your maximum HP is at your fuel cut and you know that the engine can generate more HP by raising the limit up...

Raising up the compression ratio will definitely get the HP, but you need a very good experienced tuner to tune the car because once again, it is the reliability that you want to get from the engine... and of course.. the power.

cheers,

richie

 

What excat is raising compression ratio? Does it mean to bore the engine bigger? What do I need to change internal to run safe with a high compression ratio?

 

Do a search online and you might be able to find some interesting reads... and also get to know more about it!

http://www.projectbronco.com/Technic...ession%20Ratio

cheers,

richie

 

You won't need a "new crank" if you want to rev high.

To begin with i don't think the VQ35 has a reliable rod ratio to be revving so high(8000 RPM like discussed). You will need to balance/blueprint the bottom end rotating components, reinforced bulletproof valvetrain and forged rod/piston setup(This is just probably a short list of what you'll need) Remember this is IF the motor makes power up their. Does anyone also know the limits on the OEM sleeves? High compression/forged setup/higher revving motor can definately put some load on the OEM sleeves that are not designed to rev so high. To rev high IF the motor makes power(higher comp, high lift cam, headwork, tune) some serious $$ would definately be needed. Weak spots on the motor would defiantely need to be spotted to build a high revving setup. A malfunctioned OEM designed oil pump or timing belt due to high RPMs can cause disaster in less than a second. All motor game is a bit different. I don't think anybody but JGTC race engine builders would know the weak spots of the VQ motor, so a 100% accurate response probably cannot be given out on this thread unless we have some experiences all motor VQ engine builders on here. Yet that's my opinion

 

i guess going FI is the cheapest/easiest way to get more hp~ huh~
sigh~ i just love the tone of high RPM

 

Well there are many people starting to take the NA route and exploring, so I doubt it will be too long before a basis for NA tuning can be laid out.

For the poster asking about compression ratio- by raising it you are changing out the pistons to piston with a "higher dome" essentially so that more air can be compressed in the cylinder during combustion. Unlike FI where the turbo compresses the air, you are using pistons to change the cylinder volume.

Fuel and timing play a huge part in NA tuning, choosing the right parts to go together also plays a huge role in the NA game. Take a look at some built Honda motors, if you throw a bunch of parts together without calculating you can end up with an expensive motor that is hard to tune and doesn't make the HP you are going for.

Many people (IMO), think of high compression and think of numbers like 12:1 or 13:1, when in reality just a slight bump to maybe 11:1 might make it just aggressive enough to get decent numbers and tune to run safely. I know when I was into Honda's everyone jumping on the NA bandwagon assumed higher was better but a tunable and safe bump in compression produced the most impressive, "consistent" results. Just a thought. Sorry to refer to Honda so much, but thats the only imports motors I've messed with that build for high c/r and all motor results.

 

thank you so much for the information. I used to have a honda civic too~ It was fun^^