Ashkellybarr Posted October 7, 2019 Share Posted October 7, 2019 Think 2.5” would be to small for a 2.4L turbo with 10:1 comp and high rpm? Quote Link to comment Share on other sites More sharing options...
kpr Posted October 7, 2019 Share Posted October 7, 2019 Bigger is better. Less exhaust pressure. Better spool. Less manifold pressure, less heat build up and less likely to knock. Not saying 2.5 wont work. But i would be going 3" 3 Quote Link to comment Share on other sites More sharing options...
Truenotch Posted October 7, 2019 Author Share Posted October 7, 2019 53 minutes ago, kpr said: But i would be going 3" I'm glad nothing's changed since this thread started in 2013. 3" is king. 7 1 Quote Link to comment Share on other sites More sharing options...
Testament Posted October 10, 2019 Share Posted October 10, 2019 On 07/10/2019 at 13:17, Ashkellybarr said: Think 2.5” would be to small for a 2.4L turbo with 10:1 comp and high rpm? TBH with that setup id even be looking at 3.5" for at least the front section does depend how much hps and rpms you are talking though. and how much you value the free hps and quicker spool less backpressure nets you. 1 Quote Link to comment Share on other sites More sharing options...
Ashkellybarr Posted October 11, 2019 Share Posted October 11, 2019 Sweet I’ve got 3” straight of the turbo for the down pipe, reduces into 2.5 just past the bottom of the fire wall. Hard case fuel and brake lines are on the inside of that chassis rail. might need to relocate them while its all a part.. Quote Link to comment Share on other sites More sharing options...
locost_bryan Posted October 14, 2019 Share Posted October 14, 2019 Quietly sporty system to suit '70s Pommie four banger with 100-120bhp - 2" pipes big enough, with a couple of Coby-style mufflers, or a two-box at the front and a resonator at the back? Quote Link to comment Share on other sites More sharing options...
mjrstar Posted October 24, 2019 Share Posted October 24, 2019 The table on the previous page has peaked my interest, my pos racecar runs a stock b18cr which when new was probably good to a touch under 200 flywheel hp. It currently has a thin walled 2 1/4 stainless exhaust system... I could go and make a new system but it would be heavier and I'm 50:50 as to whether there would be any benefit. (based on 185hp listed for me 2 1/4 system) Ideally a quick dyno session of a 3 inch side pipe vs the current full system would answer my question i guess. But i'm not really excited about spending monies on this thing. 1 Quote Link to comment Share on other sites More sharing options...
Spencer Posted October 24, 2019 Share Posted October 24, 2019 I think its basically a fact that all hondas go harder with a 3" zaust? Just have to put up with the noise. You can probably dig through the dead forums and find a million dynos on honda shit (with dead pic links ). You definitely can for K20/24 every combo of parts has been tested if you look. 1 Quote Link to comment Share on other sites More sharing options...
Testament Posted October 24, 2019 Share Posted October 24, 2019 25 minutes ago, Spencer said: big is good 2 Quote Link to comment Share on other sites More sharing options...
ajg193 Posted November 3, 2019 Share Posted November 3, 2019 Looks like the baffle is broken in my starlet's muffler. I pulled the back half of the exhaust off of the car because it sounded like there was a stone rattling around in the rear muffler. It seems to be something similar in length to the muffler itself, so I guess it is the baffle. What should I do? (It's a stainless exhaust system if that influences any opinions.. I also want the car to be quiet) Quote Link to comment Share on other sites More sharing options...
kyteler Posted November 3, 2019 Share Posted November 3, 2019 Stainless? That's not stock. Put a mild steel muffler in. It'll be fine. What pipe dimensions, etc? Three quarter inch for the massive powerhouse K-series? 2 Quote Link to comment Share on other sites More sharing options...
ajg193 Posted November 3, 2019 Share Posted November 3, 2019 1.5", stainless section has a date code of AUG03 on it 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted November 3, 2019 Share Posted November 3, 2019 Been wondering how much weight difference there is for different pipe dias. So from 2.5" OD (63mm) to a 3" (76) with the thicker walls theres about 2kg difference In order for 2kg to pay itself off in terms of power/weight you only need to gain the tiniest fraction of power, like, 1hp and it's worth it 2 Quote Link to comment Share on other sites More sharing options...
Bling Posted November 3, 2019 Share Posted November 3, 2019 19 hours ago, ajg193 said: What should I do? (It's a stainless exhaust system if that influences any opinions.. I also want the car to be quiet) Grab new muffler from Autobend, zap it on and good to go. Quote Link to comment Share on other sites More sharing options...
kpr Posted November 4, 2019 Share Posted November 4, 2019 11 hours ago, Roman said: Been wondering how much weight difference there is for different pipe dias. So from 2.5" OD (63mm) to a 3" (76) with the thicker walls theres about 2kg difference In order for 2kg to pay itself off in terms of power/weight you only need to gain the tiniest fraction of power, like, 1hp and it's worth it OD: 76mm Wall 2mm 2.5m = 3.14kg pir2 halve your weight double your power and prepare to weld it back together when it falls apart : Aluminium 3 1 Quote Link to comment Share on other sites More sharing options...
Bling Posted December 18, 2019 Share Posted December 18, 2019 3AU 1500cc. I had a front pipe bent up a while back in 1.5" to carry on from the existing 1.5" pipe. Charts say 80HP would be max for that size (I won't make that I don't imagine). Am I better off starting the lot again and upsizing the pipe, or will 1.5" be sweet? Looking to buy a combo bend setup, reso and muffler, some straight pipe, prices of which won't vary much between diameters I don't imagine. Easier to stick with 1.5", but if that will be shooting myself in the foot a bit, i'll upsize it. TIA Quote Link to comment Share on other sites More sharing options...
Spencer Posted December 18, 2019 Share Posted December 18, 2019 If you aren't building a mike-e spec 3A then just run whatever is easy/stock unless you want loud noises. 1 Quote Link to comment Share on other sites More sharing options...
Bling Posted December 18, 2019 Share Posted December 18, 2019 Certainly won't be doing that haha. Sweet thanks for that, will add on to what I have then, don't want loud noises. Just not keen on keeping the current system and finding out after five minutes of running it's full of holes. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted December 18, 2019 Share Posted December 18, 2019 Run a 3" on a 3A for all the lols 3 Quote Link to comment Share on other sites More sharing options...
kpr Posted December 18, 2019 Share Posted December 18, 2019 3au ; The one exception to the 3" rule 2 3 Quote Link to comment Share on other sites More sharing options...
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