hey guys running a holset super 40 turbo on my car and have a 3 in DP to a 3 in exhaust, and, see its choking the motor up a bit, and looking to redo the exhaust with a 4in DP and 4 in exhaust, just need your opinion on this, should i run a 4 in DP and 4in exhaust all the way back? or should i do a 4in DP then going to a 5in exhaust all the way back?....benefits and opinions on both? (also correct me if im wrong but the 3in all the way back isnt enough flow for this large turbo)?
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Google rs2002 running that setup with 3.5 inch dp just fine -
I'm running 3" out of my Comp CT43-6768 BR and 3.5" DP with 3.5" to the rear where it transitions into dual 3.5" and then right down to dual 3". Works good enough for 755hp at the wheels with more on the table.
Hap, wit dakine exhaustion tales not from Evahboost, MaguireComment
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a 3" exhaust shouldnt be choking up the engines we run...no matter what power we're running really. 3" is used on alot more powerful, heavy breathing boosted bengines just fine!1996 Audi S2 - 295bhp and 326lb/ft - Complete Rebuild Project
1994 Audi 80 - 2.0 8v (slow but reliable!)Comment
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A 3@ will choke these engines if you have boxes if you have none then it would be fine but a bit unrealistic?Comment
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I have posted this more than once before but here you go.
This chart is one I made years ago and was taken from S.E.A testing on an engine dyno, not theory.
Pipe bore size. BHP obtainable without
inch / mm pipe causing restriction.
2 / 50.8 --- 185
2.25 /57.15 --- 235
2.5 / 63.5 --- 285
2.75 / 69.85 --- 350
3 / 76.2 --- 415
3.25 / 82.55 --- 490
3.5 / 88.9 --- 565
3.75 / 95.25 --- 650
The above figures are based on petrol engines running a full length exhaust system 4 metres / 13 feet in length with free flowing silencers . Much more HP is obviously attainable from each size of pipe but beyond these figures the exhaust is increasingly restrictive .Comment
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I wouldn't agree with the above too genericComment
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Ha, the fact that don't agree with it proves nothing other than you ignorance.
It really doesn't matter that you don't agree with it as as I said it isn't theory its
actual testing.
It doesn't matter if you use a turbocharged engine or NA for this purpose as was
stated when the testing was done.
The stated figures are when the pipe dia is at the point of causing a restriction in flow that would START to reduce power output, this doesn't mean you cant push 50% more through any given dia of pipe just that beyond the sizes quoted you are losing potential output.
The post was for ref purposes and yours was for your own ******** disagree with everything
mentality, when you don't have anything useful to add why do you always feel the need to try and
put other peoples info down, ego problem ?Comment
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easy guy's it xmas,let not fight over differen't opinions.
merry xmas and a happy new year.
[SIGPIC][SIGPIC]/SIGPIC]92 3B pearl white=gone back home to Germany,probably in bits and pieces
RS2 VOLCANO BLACK] soon to be broken to bits
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Bad day? Lol over a post that said its too generic in real world tuning the real restriction that is considered is back pressure
Those figures whilst born from your testing never would apply to real world applications for instance 3" to 415 bhpComment
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Buy the way, can you not read ?
Were does it say 3 inch to 415 HP, what it says is that beyond this point the 3 inch STARTS to restrict power, it also says more but if you don't read it properly that's not my fault.
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At what temperature and by how much is engine/setup dependant.
Volcano ABY coupe
AntComment
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Both are irrelevant, your set up, how rich you are running, timing etc are what gives you your potential HP, what this means is if your given set up, mixture, timing, etc etc gives you 350hp and you are using a 2.5 inch pipe then just changing the pipe to a 3 inch will give you more power, simples.
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