To all who own a turboed datto:

What diameter exhaust do you run and what size motor do you have?
Did you notice an increase in power when changing exhaust size?

What is the standard size the silvia comes out with? I am thinking of going a 2.5" for an SR20DET. Anyone recommend this or should I go for a 3" (but that seems pretty big, considering most of the GTR systems are around 3" and they are 2.6 litre with twin turbo's!)

Let me know!

goin from tech reading and mates with turbo cars experience.. generally speaking it depends how good the factory exhaust is, and the intended power rating of the engine once finished, but usually you will gain gain a slight amount of power. this not is not only due to the less exhaust restriction, but the few PSI the turbo gives out because of less restriction

correct me if I am wrong but the bigger the exhaust means better flow for the turbo seeing you do not have too much back pressure. I am running a 3" with 2 mufflers on mine and it runs well and is not too loud in the cabin which is a must because I had noisy cabins noisy out site fine but not inside that way u can have a meaning ful conversatino and not have to yellabove the exhaust

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Cheerio

Mick Taylor
http://www.drive.to/MT510
SR20DET Datsun P510/1600
OZDAT MEMBERS PAGE
http://www.ozdat.com/forum/viewtopic.php?t=8470
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I've got a 4" in the GTR
well actually it's a metric size (its a Jap system)- just under 4"
It has a removable silincer that brings it down to around 2.75" at the tip,
and drops the noise levels from over 100db to smack on 90db....
I notice the power difference a _lot_ with it remove....
On the dyno it's worth about an extra 10kw with it removed...

So a big system and big mufflers will be easier to keep flowing well, and easier to keep the noise levels down (with out loosing too much power)
I say go the 3" for sure

A turbine works via a pressure drop across the turbine wheel. Thus there are two ways of extracting more force from a given wheel, increasing the pressure pre-side, or decreasing the pressure post-side.

Having a large diameter/low restriction exhaust improves turbocharger function via this second method - obviously.

Dave

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USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD

Can anyone tell me what is the standard size exhaust the silvia comes out with?

AND

Has anyone carried out an exhaust upgrade on one of their turboed cars without upgrading anything else? (obviously a dyno tune inbetween!) What sort of performance increase did you notice?

FJ20et, 4" sidepipe

2 1/2" or 3" is what you want for a turbo, when you get ity make sure you get mandel bent or you will loose alot of flow.

i have a 3' mandrel bent exhaust on my FJ20 Turb bluey.

as everybody says the more flow the better but i wouldn't think you would make more power with a say 8" exhaust than you would with a say 4" exhaust, i think going to big 3 1/2" 4" is just for wank factor especially on a 4 cly and even probably a 6.

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Nissan Bluebird - S15 SR20DET
Nissan R30 Skyline - RB26DEmassiveT Project car
Nissan R32 GTR - RB26DETT