scotteslic Posted April 11 Posted April 11 What is the advantages and disadvantages of each Thanks in advanced, Newbie Scott Quote
peter1127 Posted April 11 Posted April 11 I would say blow trough is the better solution, draw trough has some advantages but for the street it has too many disadvantages, driveability being the main one. draw trough con hot turbo under the tank: vapor lock exhaust close to your leg Longer exhaust pipes so more lag One large carb Hard to add an intercooler Turbo seals needs to be able to deal with the fuel Turbo needs to be able to deal with vacuum Fuel can be unevently divided between cylinders: 1&4 tend to be leaner, or difference between 1-2 & 3-4. Sometimes a divider is added to counter that (Iguess you could add 4 injectors in the plenum and have the carb replaced by a large throttle body) If the engine backfires you back is literary on fire because mixture is in the whole intake area (compressor housing, and plenum) Very violent on/off performance especially on large turbo big power bikes Difficult to add a muffler draw trough pro easier to set up the one carb, because there is no pressurisation of the carb and its very easily accessible No FPU needed No pressurized carb needed Gravity drain of the oil is easy Front wheel clearance is not a problem Very violent on/off performance especially on large turbo big power bikes looks really oldskool and cool and imo the only good reason to do it Blow trough con Setting up the carbs can be difficult (could be mitigated by adding injection but that also has its challenges) Carb sealing can be a challenge, fuel pressure is critically important to stay in that sweetspot between leaking and fuel starvation and so is float and needle/seat condition. (Again could be mitigated by adding injection but that also has its challenges) Front wheel clearance especially on larger turbo's. I bought header and turbo at proboost and that fits nicely. Still need to experience emergency braking front wheel clearance........ oil return need most of the time a pump. Can be electrical or mechanically. You could try gravity drain but if turbo sits low it can smoke like a mf Blow trough pro Off boost behaviour is much nicer, depending on CR it can be close to stock so suitable for the road Intercooler is possible No special seals for fuel and/or vacuum are needed Easy to add a full exhaust No issue with AFR being different per cylinder (unless fuel injection, then that could happen with poor plenum design) Even without intercooler intake air is cooler so more detonation resistant = more boost = more power 7 Quote
Gixer1460 Posted April 11 Posted April 11 Draw through comments all fairly valid IF using a carb solution! Most, if not almost all go away, if you use an injected solution. Plus Draw Through is Oldskool Cool! 3 Quote
imago Posted April 11 Posted April 11 5 hours ago, peter1127 said: Very violent on/off performance especially on large turbo big power bikes looks really oldskool and cool and imo the only good reason to do it Agree with all of the post, especially those two points as they are exactly the reason I went for a draw through. 6 hours ago, scotteslic said: What is the advantages and disadvantages of each Thanks in advanced, Newbie Scott The first/main question is, what do you want to use it for most often? Quote
scotteslic Posted April 11 Author Posted April 11 7 minutes ago, imago said: Agree with all of the post, especially those two points as they are exactly the reason I went for a draw through. The first/main question is, what do you want to use it for most often? Street bike not too radical Quote
Arttu Posted April 12 Posted April 12 EFI with injectors placed on the intake ports should solve most of the fueling issues with draw through setup. But you will still need a carbon sealed turbo... Regarding original question, I think blow-through is technically better in almost every way. So only reason to select draw-through is that you specifically want it, for example because of style and look. 4 Quote
scotteslic Posted April 12 Author Posted April 12 Would you put a O² sensor in each exhaust tube with allow through Quote
Duckndive Posted April 12 Posted April 12 9 hours ago, Arttu said: EFI with injectors placed on the intake ports should solve most of the fueling issues with draw through setup. But you will still need a carbon sealed turbo... Regarding original question, I think blow-through is technically better in almost every way. So only reason to select draw-through is that you specifically want it, for example because of style and look. There's a couple of really sweet runners using a single throttle body and injector on Faceache the videos may be on youtube not sure if he's on OSS but Ade Rix did a real sweet one Quote
Gixer1460 Posted April 12 Posted April 12 2 hours ago, scotteslic said: Would you put a O² sensor in each exhaust tube with allow through Waste of time and due to proximity to cyl. head or upstream of turbo (depending on style chosen) would likely fail in short order! A single sensor after turbo is usual placement but be warned if running a shortie dump pipe the sensor can be confused with atmospheric oxygen due to sensor being close to exhaust exit! Try not to fit before turbo as pressure and elevated temps not good for them! Quote
Arttu Posted April 13 Posted April 13 11 hours ago, Duckndive said: There's a couple of really sweet runners using a single throttle body and injector on Faceache the videos may be on youtube not sure if he's on OSS but Ade Rix did a real sweet one Sure it's doable that way too. But if you inject fuel before the turbo your fuel distribution between the cylinders is at mercy of the intake manifold design. Quote
Arttu Posted April 13 Posted April 13 12 hours ago, scotteslic said: Would you put a O² sensor in each exhaust tube with allow through Usually not. It would be relatively complicated and expensive. Also there are some issues with placing the sensors before the turbo like @Gixer1460mentioned. Although it's doable if you really need to. Normal solution is to have a single O2 sensor after the turbo. And if you want to monitor individual cylinders exhaust temp sensors are quite good for that. 1 Quote
Duckndive Posted April 13 Posted April 13 5 hours ago, Arttu said: But if you inject fuel before the turbo your fuel distribution between the cylinders is at mercy of the intake manifold design. Some Do Some Don't The Wizzer Blows the Engine Suck's i never had any issues using this 2 Quote
scotteslic Posted April 13 Author Posted April 13 Instead of individualizing everything, use one O² sensor, 4 injectors tied together in the intake runners and one throttle body in a blow thru set up Sorry for all the questions Quote
Arttu Posted April 13 Posted April 13 (edited) 9 hours ago, Duckndive said: Some Do Some Don't The Wizzer Blows the Engine Suck's i never had any issues using this That's exactly what I meant. It can work right away if you have a good proven setup, if you are lucky or if you happen to know exactly what you are doing. But it can be be much more difficult as well... Edited April 13 by Arttu Quote
Reinhoud Posted April 30 Posted April 30 On 4/13/2024 at 12:03 AM, scotteslic said: Would you put a O² sensor in each exhaust tube with allow through I tried that, but because of the short manifold, the short runners influence each other, so you don't get a proper reading. At least, that happened with mine. Quote
peter1127 Posted April 30 Posted April 30 On 4/12/2024 at 6:17 PM, Gixer1460 said: Waste of time and due to proximity to cyl. head or upstream of turbo (depending on style chosen) would likely fail in short order! A single sensor after turbo is usual placement but be warned if running a shortie dump pipe the sensor can be confused with atmospheric oxygen due to sensor being close to exhaust exit! Try not to fit before turbo as pressure and elevated temps not good for them! Tried that before. Failed within 5 min. Quote
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