Once again sorry for being a newbie and asking a question that has probably been asked a million times but it is difficult to narrow down what I am looking for using the search function.

I am taking my EVO to the track for the first time Friday night and I want to get a boost controller second day aired to me tomorrow before going.

I have heard a lot of guys say that the car is FINE at 19PSI on the stock internals and it poses no threat to the motor. Is this really true? Let me be clear in saying that I am far more concerned about reliability than HP but I wouldn't mind turning the boost up if hte motor can handle it. I would only be running it at 19PSI at the strip...not on the strip.

What do you guys think? Am I going to blow my motor at 19PSI? Also I live on the east coast and we have 93 Octane...and we even have a place that sells 103 Octane but it is $$.

 

I thought the Evo had 19.5psi from the factory?

 

yea that is why I made this thread. I have heard some say 19, some say 17 and some say 14...i'm very confused.

 

Well im not to fimilar with the Evo yet, Ive just started to look at them.

Im not sure what size fuel pump it came with , Im amagining a larger then with my GSX. My GSX stock handles 15psi for the last 2 years. Im soon to move on to a 190 Walbro pump, But Im sure the Evo came with a larger pump.

Im not saying turn it up, Im just saying Im sure it can handle a bit of extra air.

With the right fuel that motor can easily handle 24 psi just like anyother 4g63 has. But once again I have to say im not fimilar with the new changes.

Id do some more research and look to see what size fuel pumps stock on the car, then go from there.

Hope I offered alittle insight.

Also I would really say get the 102 , If its unleaded its worth every cent at the track!

 

It has a 19.5 PSI spike, at the low end where fuel is plenty and knock is low or not there, then it immediatly falls back down to 16PSI unless you haven't tightened the BOV clamps, then it has a good chance of leaking, I tightened mine last week, finaly hit 19PSI.


19PSI to the red is FINE, but tuning the car along with it would yeild MUCH better results, hell WORKS ecu actually makes a 50WHP increase at 7500RPMS.




Granted that this stock dyno plot is kinda low, may be accredited to the DYNO reading a little off, BUT the power increase is VERY real, and this car is stock except for a reflash, and look at the stock power (BLUE LINE)at 7500n (195WHP) vs the new one at 246WHP, that is a 50WHP increase RIGHT where you need it, up top is right where this engine belongs. All this as the boost falls off to 16PSI, all in tuning, now this curve would go up with boost to a point of detonation.

I plan on getting this mod, some grounding wires, a BR intake, and then remove the stock soleniod restrictor which will give me about 18PSI to the red, if there is no knock, I should make abother 10-20WHP on top.


These cars love boost, but if it isn't tuned right, even 7PSI will blow a motor up.


Turning up the stock boost? Iduno, I'll tell you this weekend after I get back from E-Town.

 

try a search, but the stock motor can handle 28 lbs and your turbo has a max of 25

 

hell 30psi is fine with fuel and tuning, but the head bolts are only god till about 25PSI, then your head may lift, but ARP blts are like $100 so an easy fix.

 

Thanks guys for all the replies. This board is great!

 

For the record, 30 PSI on a properly fueled and tuned 4G63 will give you well over 600 HP at the wheels...

 

Can I have an AMEN!

I LOVE these motors!

 

awesome...

 

Doesn't make sense to me. From what I am reading a stock car runs 16 PSI (~31 PSI absolute a sea level) and is rated 271 crank HP from the factory. 30 PSI boost would be ~45 PSI absolute pressure at sea level. Now this is what I know, doing a very rough calculation:

271 crank HP * 45 PSI / 31 PSI = 393 crank HP.

Now I've owned turbo cars for a number of years now an know exhausts, intercoolers, and so on play a large part in the actual HP numbers. I also know that phyics dictates that higher boost means hotter air, not good for HP. None of these positive and negative effects are taken into account above. I just don't understand how 30 PSI of boost translates to over 600 wheel HP when the crank HP would appear to be in the neighborhood of 400 HP. Keep in mind too that drivetrain loss on AWD cars is pretty high too.

So I don't mean to sound like a jerk on my first post, but I just don't see how such a number comes about. But I am very willing to learn if someone has a good exlpaination!

Peter

 

A 4g63 is very competent of making suck power peteS4.

Well the whole higher boost = high intake temps isn’t really true.
Between larger turbos, intercooler cores water injection, NO2 and proper tuning you can yield power till your empty wallets on Ebay.

David Buschur of Buschur Racing is only pushing 28psi with I believe a 45 shot of NO2. He's well into the 7.30s in his 4g63 powered tube chassis talon.

With the larger the turbo the cooler the temps, a stock 16g is good to 23psi or so, but with every psi above 18-20 its efficiency drops dramatically. 23 PSI from a L2R or similar large thumper turbo is a cool breeze when compared to a td05 series turbo (16g or similar).

Power doesnt lie 100% with in PSI, its the fuel and psi that mate together to make numbers.

Hope I helped.

 

Pete,
The post says on a properly fueled and tuned motor, which on 30 psi means 720 cc injectors and a ton of supporting mods. So as far as explanations go, the motor will make 600+hp with 30 psi but it takes a lot of other mods and NOVA EVO was just making a broad statement.

 

Kevin,

If you bump up the boost I'ld throw some race fuel in just for a little extra safety. If I were you I'd spring for some 110 over 103. By the time you mix 103 with 93 the gains aren't nearly as significant as they are with 110.

Forget the (R+M)/2 ratings... which is the "93" in 93 octane pump gas. It's meaningless - well almost - when talking about true knock resistance.

Sunoco 104(R+M)/2 is only a 99 motor rating.

The 110 (R+M)/2 is a 105 motor rating... the 112 (R+M)/2 which the Sup drinks is a 110 motor octane.

Anyway... either run out most of your pump gas and then use some 104... or if you have quite a bit of fuel in your tank add some of the more potent (and expensive) higher octane. It's probably overkill... but better safe than sorry.

Also keep in mind that the stock ecu will start to pull timing if it hears knock. The good fuel will let it run more timing and give you more power... at least thats how the Supras ECU works. I'm sure the EVO is very similar.

Have fun and be gentle with that clutch!

Gimme a call when youre ready for big injectors, twin pumps and a staedy diet of 112 octane fuel.