ok ive seen the lower boost ports in the intake that connect to the transfer tunnels, but what about the upper two that connect right to the transfer window? is there any evidense that this would work or make more power? or some kind of fancy gimmick, because if someone has proof or something that this works i might do it on my cylinder that should arrive soon, im gonna port it anyways myself, and im wonder if these boost ports are worth it.
4 boost ports in the intake?
- Thread starter yfz450bence
- Start date
I also plan on using a 1.5mm base plate spacer with just high temp sealant on both sides of the spacer, this will fully uncover the ports, my head is mille .040 right now so i think it should put it at 145 psi area, ill have to find out then. as long as compression is ok i dont need to mill the deck do i?
are u talking about a spacer plate like the vitos spacer plate for the +3mm cranks, on a stock stroke engine?
no not vitos, this is 1.5mm thick. this will be a stock bore and stroke motor, but with a thicker base gasket if you will, to raise the cylinder a bit for better timing area, free hp is to be had by raising the cylinder just enough to uncover the ports. i guess ill find out myself how much compression it has when its put together next week. when the piston is a bdc, the piston covers the transfers 1mm maybe more depending what base gasket you use. its like having a nice little port job by raising the jug.
but any input on those boost ports would be great, they look pretty easy to do, just dont know if its worth it
but any input on those boost ports would be great, they look pretty easy to do, just dont know if its worth it
honestly man, when it comes to porting i pay someone lol, i have the boost ports or "boyeson ports" that FLOTEK put in my motor to match the +3 stroker but hes the pro, and all i know is the blasty is sick fast, but as far as putting a spacer in, on a stock stroke, isnt that going to enlargen the combustion chamber on the head, thereby dropping ur compression?
a thicker base gasket will increase the squish clearance which already sucks and it will not change your blowdown almost at all which is a huge problem if you want mroe torque also it will not be a benefit for the piston down at BDC as all the transfers and exhaust are incorrect due ot a wall there which is already a big problem on a blaster jug in stock form and youll be making it worse.adding more boost ports beyond 2 extras leading ot the transfer jackets wont make much of any more power ,trust me i have ported these 6 ways to sunday and your wasting your time ,in fact you could turn the intake into swiss cheese and you wont gain much of anything you will actually lose intake velocity if you go too big resulting in poor lowend torque and erratic throttle response ,all in all most of the power is found in the transfers and exhaust design ,takes alot of ported jugs for testing and years to get broad power out of them.
ok thanks for the response, i know the squish isnt good, but the head is milled to compensate for it. i dont undertand the wall thing, this will just increase the timing a bit. i dont plan on opening up the intake like crazy, and ive ported these cylinders before with good success, the question was about boost ports mostly, and i already have the specs on how much i plan to open up the exhaust and transfers. in fact i dont mind sharing what i did on the first cylinder i ported, i raised the intake a bit, and raised the exhaust 5mm and widened it like 10mm lol basically you couldnt widen it anymore before you hit the transfers, let me tell you this thing was *ucking nuts. was re liable for a long time
and a dune runner with not much low end. unfortunetly my dad rode it and was in 6th gear at the dunes with no paddles and blew it up due to over reving it in that gear for so long, the pistion actually didnt look to bad. and i dont plan on porting it like that now lol
ill give you an honest report on how it ends up running next week on this thread. with the crappy squish area and base plate spacer lol. if it really sucks for some reason, ill throw on a standard gasket. no harm done
and a dune runner with not much low end. unfortunetly my dad rode it and was in 6th gear at the dunes with no paddles and blew it up due to over reving it in that gear for so long, the pistion actually didnt look to bad. and i dont plan on porting it like that now lol
ill give you an honest report on how it ends up running next week on this thread. with the crappy squish area and base plate spacer lol. if it really sucks for some reason, ill throw on a standard gasket. no harm done
i plan on doing it right and getting the head decked, i will get the squish down to .3mm to .4mm as a target, plus a top end gasket, which will put me at 1.2mm with a head gasket, better than stock which is around 1.6mm. should rip
you should maintane a 70% chordial width to the bore size or it will eat rings ,thats why it didnt last ,there are certain parameters that must be kept .your poor lowend probably came from having such high exhaust timing and the dramatic blowdown (duration relationship between transfers and exhaust) that makes for sucky off idle snap and makes for a torquey but narrow powerband.
Not to mention the chance of short-circuiting the ports if you widen the exhaust port extremely and don't pitch the transfers to compensate. This means that some of your incoming charge is sent directly out of the exhuast port, which equals a loss of power compared to what it could make.
i know, it was bad yes, that was a while back. this time reliability will be 1st priority
I was hoping for some clarification on the "transfers and exhaust are incorrect due to a wall there" portion of your post...
I would tend to agree with MacDizzy on the advantage of adding a 1mm base spacer plate as it allows the transfers and exhaust to be fully uncovered when the piston reaches BDC. MacDizzy's Blaster rebuild thread can be found here. Pages with info regarding the base spacer plate can be found here and here. Do most builders just ignore the 1mm overlap at BDC? That would go against everything I've learned about airflow in a two-stroke engine. I'm new to the Blaster, but I'm trying to learn as much as I can about their engines, so your input is appreciated.
yes it does, but what he is saying is what i did, i did 2 base gaskets, then had my dad take my cyinder in and shave some off of the top of my cylinder to make up for the base gaskets. thus having same compression but clearing all the ports.
i should have read the first post in the thread a bit closer concerning bdc i see what your saying .this is more of a concern with strokers and custom applications like i was saying ,it get stroker on the brain lolI should have been more clear .on a stockstroke and his build i cant speak for him on his application but you should note that the piston used on macdizzy was not a wiseco it was a prox and gasket thickness vary.. says he also lapped the cases ,gaskets can range wildly ,some pistons have a different pin location and dome angle ,i have also seen sometimes they change the piston design every so many years .some jugs have been lapped and had material removed ,its probably never a good idea to make a wide sweeping statement about that when their are so many variables if you want it exact .banshees have the same situation on two of their transfer ports and no one uses thicker base gaskets to try and correct it ,persoanly i would not add more complexity into the mix if you can help it .see all these variables can change the final result the only true accurate way to get that exact amount you want to change is to have the engine as a whole and check it out and see where it lies and of coarse there is more than one way to skin a cat
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