How much bhp out of a modded nissan silvia s15?

[ZulaBoi]

First of all i'm not much of a car guy so forgive me if i'm being too vague and also new here so sorry if this is on the wrong thread.

As the question says I was wondering how much bhp you could safely and legally get out of a S15 in the UK, with a budget of a couple of grand. Would really help me out in an argument with my friend.

 

[TCJBOLDIE]

Well if it was my car the first thing I would do is have a power run on a dyno to see how it is performing and to have a base to compare exactly what the mods I have suggested will have on the power output after the following mods will have.
The next things to do/change would be have the injectors tested and flowed plus a new fuel filter and then have it fitted with a full 3 inch exhaust system from the turbo outlet along with straight thru silencers plus a front mount intercooler and a boost bleed valve and get it on a dyno/rolling road to check if everything will be safe and and if you wish have the tuner wind up the boost to say 15-20 psi OR what he/she considered to be a safe level for what you wish to do with the car.

 

[ZulaBoi]

Well if it was my car the first thing I would do is have a power run on a dyno to see how it is performing and to have a base to compare exactly what the mods I have suggested will have on the power output after the following mods will have.
The next things to do/change would be have the injectors tested and flowed plus a new fuel filter and then have it fitted with a full 3 inch exhaust system from the turbo outlet along with straight thru silencers plus a front mount intercooler and a boost bleed valve and get it on a dyno/rolling road to check if everything will be safe and and if you wish have the tuner wind up the boost to say 15-20 psi OR what he/she considered to be a safe level for what you wish to do with the car.

Thanks, so how much power would that yield?

 

[TCJBOLDIE]

When I had the 3 inch system fitted to the old car in my pic I had it dynoed before and after the same day and it gained app 15% more power and came on boost sooner due to removing any back pressure in the exhaust system after the turbo which allows the turbo to work more efficiently so I am speaking from experience

IMO you should get the same or more power increase from the SR20.

If you look at pics of drag cars/motors you will generally see only a short length of large diameter pipe exiting the turbine housing.

The turbine outlet is smaller than the pipe internal size .

Here's a pic 4 U

https://www.google.com.au/search?q=4+cylinder+turbo+drag+motors&tbm=isch&imgil=9z7Xn0Yk4J2HGM%3A%3BGrEz_BXK5yrarM%3Bhttps%253A%252F%252Fwww.youtube.com%252Fwatch%253Fv%25253De-N4KLq0vQk&source=iu&pf=m&fir=9z7Xn0Yk4J2HGM%3A%2CGrEz_BXK5yrarM%2C_&usg=__o2_0VwywC8Zh_mXo7Os0JHuYFkU=&biw=1680&bih=926&ved=0ahUKEwjCxdqHxp3UAhVBupQKHXREA5cQyjcINA&ei=TIEwWcLvMsH00gT0iI24CQ#imgrc=9z7Xn0Yk4J2HGM:

 

[TCJBOLDIE]

FYI Here is another pic of a twin turbo motor with twin external wastegates. They have the smaller exhaust pipes that are called "screamer pipes" which are totally illegal on a road car where they must be joined into the exhaust system to reduce the sound to acceptable /legal levels.

https://www.google.com.au/search?q=4+cylinder+turbo+drag+motors&tbm=isch&imgil=9z7Xn0Yk4J2HGM%3A%3BGrEz_BXK5yrarM%3Bhttps%253A%252F%252Fwww.youtube.com%252Fwatch%253Fv%25253De-N4KLq0vQk&source=iu&pf=m&fir=9z7Xn0Yk4J2HGM%3A%2CGrEz_BXK5yrarM%2C_&usg=__o2_0VwywC8Zh_mXo7Os0JHuYFkU=&biw=1680&bih=926&ved=0ahUKEwjCxdqHxp3UAhVBupQKHXREA5cQyjcINA&ei=TIEwWcLvMsH00gT0iI24CQ#imgrc=hj_RVF570WTZdM:

 

[obi_waynne]

There is no legal power limit here in the UK but you do have to watch your emissions levels.

Turbo upgrades are the key to larger power gains.

 

[TCJBOLDIE]

[QUOTE="obi_waynne, post: 302958, member: 2"

Turbo upgrades are the key to larger power gains.[/QUOTE]

I agree BUT one needs the basic upgrades I suggested before or at the same time you upgrade the turbo.
You may also need to upgrade the fuel pump and injectors as well at this time to remove the possibility of not having enough fuel flow for the increased power from the new turbo and ending up with a blown motor due to the lean Air Fuel ratio causing detonation and ending up with holed pistons and or broken ring lands .

I always take my car to my trusted dyno tuner to ensure that any mod or change/upgrade is safe.