How much boost to run

[nrcooled]

Curious how much boost I can run on a stock sr w/ smic.  I was told no more than 10psi but then some people say I can run more w/o running lean.

Any suggestions or info would be greatly appreciated so I don't blow up my baby <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>

[Ser_rah]

Just a newbie taking an honest shot here, but I hear 14psi is pushing it if all the wind,and spark are timed properly. &nbsp;12 is the most that normal people run. &nbsp;Those who respect their engine's ability to blow up will run. &nbsp;
&nbsp;I don't have a det though so maybe someone with one would know better.

[phatdex]

Not really worth boosting a stock engine. &nbsp;Get a 3.5" exhaust, front mount intercooler and then boost it to about 12psi max.
An exhaust will raise boost automatically and FMIC will lower it. &nbsp;But just those two mods will make a much better improvement than boosting it.

[Arcane]

an sr with stock internals can handle the 14psi....i wouldn't go higher than 10...

[RedSuns]

how about a stock S14 SR20DET....i have a FMIC for it and an open exaust...what can I be safe at.....i want to run 10psi normally....

[oberkill]

Ok we have been through this before I believe but its been awhile. Some of the posts above are conservative to say the least. Here are my opinions:

On a stock SR with sidemount assuming stock fuel pump so not go higher than 10 PSI.

With a aftermarket fuel pump you can run 12 no problem.

If it were a nice cool day and you had some race gas 14 would not be a problem, though you will not get the best efficiacy. The engine will handle that no problem.

The SR with stock everything will handle quite a bit of boost, the real limitations are fuel and intercooler. The 370's are pretty much maxed at 17 psi off a T25 (this is assuming a aftermarket fuel pump, the stock fuel pump is really only good to about 10 psi) Greaser was running a stock redtop with upgraded fuel at 15 psi on a GT3037 which flows alot more than the T25. Its all about tuning.

Alan

[oberkill]

<!--QuoteBegin--phatdex+April 25 2002,9<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (phatdex @ April 25 2002,9<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'>0)</td></tr><tr><td id="QUOTE">Not really worth boosting a stock engine. Get a 3.5" exhaust, front mount intercooler and then boost it to about 12psi max.
An exhaust will raise boost automatically and FMIC will lower it. But just those two mods will make a much better improvement than boosting it.</td></tr></table><span id='postcolor'>
I dont want to call someone out but what the hell are you talking about? With those two mods (assuming a new fuel pump) 12 psi is nothing. Those mods are really for a big boost/turbo application. I would not reccomend a 3.5 inch exhaust on a stock turbo setup unless you plan on upgrading later and adding that would lower the boost not raise it. A single core front mount is a good upgrade and I highly reccomend it but a big intercooler like the Greddy R-SPL is a waste on a stock SR. Greddy actually says its made for over 12 psi applications on aftermarket turbo's. If you do those mods turn the boost up to 12 minimum not Max. I just want to see correct info put out I am not trying to flame you.

Alan

[boosteds14]

3.5" exhaust? i can see if it was diesel turbo but it is not.
2.75"-3" is a great &nbsp;size for that turbo and airflow that comes through

[Arcane]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (oberkill @ April 26 2002,09:20)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (phatdex @ April 25 2002,9<!--emo&<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'>)</td></tr><tr><td id="QUOTE">Not really worth boosting a stock engine. Get a 3.5" exhaust, front mount intercooler and then boost it to about 12psi max.
An exhaust will raise boost automatically and FMIC will lower it. But just those two mods will make a much better improvement than boosting it.</td></tr></table><span id='postcolor'>
I dont want to call someone out but what the hell are you talking about? With those two mods (assuming a new fuel pump) 12 psi is nothing. Those mods are really for a big boost/turbo application. I would not reccomend a 3.5 inch exhaust on a stock turbo setup unless you plan on upgrading later and adding that would lower the boost not raise it. A single core front mount is a good upgrade and I highly reccomend it but a big intercooler like the Greddy R-SPL is a waste on a stock SR. Greddy actually says its made for over 12 psi applications on aftermarket turbo's. If you do those mods turn the boost up to 12 minimum not Max. I just want to see correct info put out I am not trying to flame you.

Alan</td></tr></table><span id='postcolor'>
don't worry alan...i'm sure the correct info is always appreciated...although you may need to stop by and correct people more often...hehe...

[silviasichigo]

Ok let's try to claer this up. I have a 93 redtop with 45000Km on it. I have a 3.5 inch exhaust or 88pi whatever you want to say. it is perfectly normal to run high diameter exhaust on a stock SR. There is nothing wrong with boosting a stock internal sr with stock sr fuel pump. On the other side what are you boosting so high for. I dry hopp so that it is why I boost a SR with 3.5 exhaust, Greddy profec A, Apexi filter,stock SMIC, and stock fuel system. You can boost this engine safely at .92Kg/cm2 (13.1psi)on high Octane fuel and make 12 hard passes with no trouble if in between runs you take care of the car.Cool it off open the hood. I have done this for the past year twice a month. at .92Kg/cm2 (13.1psi) My S-14 is only slightly moded I am boosting &nbsp;1.02Kg/cm2 (14.5psi) The Sr is stronger than you think and will last if you use the right parts. I have had a lot of experiance with the SR I only use stepping motor Boost controllers for the fact they get you to your boost with more stability than solonoid boost controller. My friend (Junia Knows who I am talking about Mario) had a 91 S-13 with an SR he had a solonoid boost controller. Hed boosted his engine to 1.04Kg/cm2 (16psi)and made 7 passes with two passengers and did not blow until his last pass and that was with no cool down 3.5" exhaust, Stock fuel, Stock internals,and only a solinoid boost controller. He chose his own path but he boosted 16psi for 7 good hard passes. This engine can do more than you expect. The way I see it everyone here is right You have to be conservative since you don't have SR's falling out of the sky like me and Junia and some of the other members that happen to be in Japan. I am speaking from experiance nothing less. It is ok to boost a stock SR ( Internals) To 13.8 psi if you take it slow learn your engine. Start off low Go from stock and boost up until you feel comfortable with it. You will have a gain in power. I have only lost two races sice I started and that was to 2 highly Moded RX-7's I am talking easy 10-11 sec cars. I will be racing in the up coming HKS drag meet and I think I will do pretty damn good. (Junia I finally got my power FC in the car)

Put it this way becareful you boost to what is comfortable watch you guages &nbsp;get a fuel pressure guage that is the best way to test your boost. You can closely monitor it (if it has a warning light like mine) you can just look up at the warning signal and let off. Get a boost controller that has a warning boost cut feature (I preferr the Greddy Profec A) it has all the features you need. The actuator valve on the red top is not very stable and you will get a lot of boost spikes that is why I preferr a stepping motor to a solonoid. The stability issue.

[oberkill]

Doh I posted a long response to this but the board lost it. &nbsp;Basically your info does not help with US cars.

Alan

[junia]

Well, if you are planning to get another fuel pump, you can fix the stock fuel pump to run on high at all times. This trick works if you have the wiring from a stock s13 from japan though.

[nrcooled]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Doh I posted a long response to this but the board lost it. &nbsp;Basically your info does not help with US cars.

Alan
</td></tr></table><span id='postcolor'>

Are you refering to the fact that they run higher oct or is some of the info incorrect.

It sounded, well for lack of a better word, like sound info. &nbsp;I plan on running mine at 10psi for regular street use and at 12-13 when running oct boost <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/cool.gif" border="0" valign="absmiddle" alt=':cool:'>

[oberkill]

A silvia fuel pump is differant than a US fuel pump. &nbsp;I really dont feel like writing the whole post again. &nbsp;If you are running a stock fuel pump do not go over 10psi. &nbsp;if it is aftermarket than 12-13 is fine. &nbsp;The SMIC gets heat soaked very easy.

Alan

[spicy_chicken]

I'm not sure about how the psi works, but on my red top sileighty I ran 0.9 kg/cm2 boost with no problems....I had the factory side mount intercooler and a r-32 gt-r fuel pump. the injectore were still 330cc....now on my s-14 black top i'm running 1.0kg/cm2 boost. but i also put a stainless steel ex.manifold, turbo outlet pipe and a down pipe. with a r32 gt-r fuel pump and normal turbine.plus a front mount 2core intercooler. if you want to raise your boost buy a metal head gasket at least 1.2mm

domo