Thread: What size exhaust are you guys using with NA VE's?

The header has way more impact on performance n/a when compared to exhaust size. To many fwd sr ppl run crush bend exhaust with a ssac header, while better then oem exhaust this combo is not optimal. A well designed scavaging header with 2.5in exhaust will outperform a ssac or oem header with 3in exhaust. So many factors make it hard to say what's best. I run a custom 4-1 header with 3in exhaust on my ve powered b13 and my car out performs my buddies b14 with ve with ssac header, 2.5 exh and aem s2 ems. You can debate this forever but 3in exh is the best option performance wise.

Engines have been engines since forever ago and have liked as little as restriction as possible. Ask my seventy-one year-young Father who ran engine dynos at General Motors during the 1960's and later went on to building his own race car 510s to have his brother drive them in SCCA.

It is not an old school way of thinking....

DE, VE, LS, Rotary, steam engine.

Lol, exactly... 3" will work better even on stock DE. Some haters want more dyno sheets?

Stop reading 10+ old years info.

Why didn't the engineers at Nissan go with a 2.5" or 3" diameter originally? The B13 stock exhaust piping is awful. At one point it goes down to something like 1 - 7/8". Why not put a 3" exhaust on with the stock muffler? Then they could have said "the new 1991 Nissan Sentra SE-R has 145HP" or whatever the increase is. I don't think the sound would be much different with the stock muffler, it would probably be a little more throaty. We know the car companies want their motors sounding as quiet as possible because the general population doesn't want noise and just wants to get from point A to B (especially with a Nissan Sentra which was obviously meant for fuel economy). The only thing I can think of is cost, I suppose pipes smaller in diameter could be cheaper than bigger ones, I guess

Or maybe they didn't care, or maybe no one wanted to spend time and money experimenting with different pipe diameters, or maybe it would effect CA emissions, I have no idea. shrug

I dont agree. Not on a stock DE with stock exhaust manifold.

The loss will be more than the gains.

surprised none of the tech gurus on exhaust diameter mentioned response ? its great to have ooddles of power but how fast can you get to it ? or how quickly can you reach power band. Hp and Tq numbers are great for bragging rights, but no dyno can measure true response difference in piping right ? There isn't a time scale is there ? Maybe someone can chime in on that. Some may say if the response is better shouldn't a dyno be able to display more power ? a dyno will display force to wheels / crank vs rpm, maybe the engine becomes less efficient with a larger piping and shows a loss of power. Should we discuss area under the curve ? Maybe talk about big air pump engine/motor theories ? Still doesn't give an idea on response, but in a real-on-the-street application, quicker a car can get to its powerband and god willing its broad enough it can and will beat a car with more absolute power 9 out of 10 times. EJ20T vs SR20VE scenario right ?
As for OEM application of larger piping, that's a whole article in itself, anyone own or work on a V8 Infiniti sedan ? 1.75" on SR, that's fine compared to what comes stock on a V8 infiniti powered cars. Where is the Infiniti V8 F1 r&d trickle down effect ?

Ive gone with a very well made 2.5" I know I could gain more with a 3" but I plan on driving the car a lot.

The car has already made 255hp/205ftlb with a maximworxs 4-2-1 manifold and 60mm 5zigen exhaust, so with my manifold and the 2.5" catback I imagine it will make a bit more than that once its all up and running.

We have had a couple of members over here put 3" exhausts on stock RR DE motors and have made very good figures, no losses anywhere.

as for Nissan not fitting big exhausts, its not cost effective.

Transient power can be measured on a dyno... you just start your pull from different rpms. You take a look at your shift points and see what rpm the engine will have to recover from after a shift. Measuring elapsed time at different rpms ....

Yes transient power can be measured on a very specialized dyno that can datalog in real time multiple runs under various loads, or have timed telemetry data to compare. Mostly part throttle tuning/optimizing under varying loads right ? Not the same as response.
RPM over Distance can show a response difference is what I am getting at, unsure if a DynoDynamics / DynoJet graph can be included to reflect power output in the tested range.

Because nissan doesn't want you pissing off the neighbors or scaring the crap out of your mom.

I'm sorry but you set yourself up by pulling that stunt, lol.