Dimensions Of Hks 2835 Pro S Dump Pipe

[Harey]

Hi all,

Can someone help out with the dimensions of a HKS 2835 Pro S dump pipe? The one we have is a split dump pipe, the main pipe being 2.5" and the wastegate pipe being 1", the wastegate pipe merges with the 2.5" pipe before the flange to the front pipe. 2.5" at the flange seems too small to me?? Help please!

[DaveO74]

I can give you the dimensions later tonight Harey.

Just gotta get bubby off to bed then it's back to the rebuild and luckily I have a new 2835 pro s kit sitting in a box. I'll measure it up and post pics for you, might not be till midnight though ok?

[DaveO74]

I can give you the dimensions later tonight Harey.

Just gotta get bubby off to bed then it's back to the rebuild and luckily I have a new 2835 pro s kit sitting in a box. I'll measure it up and post pics for you, might not be till midnight though ok?

Ok here are the pics of the dump how it comes from hks with the product code on the bag

A couple of the actual dump so you can compare

The bottom of the dump (Front pipe end) measures around 70mm so thats about 2.75inches???

The top of the dump (Rear of the turbo end) is a little less than 40mm wide x 80mm long for the wastegate part (2 pipes welded together in a funny shape)and the main pipe around 65mm so around 1.5inch x 3inch for the W/G and 2.5inch for the main pipe

Is this the same as yours Harey??

Mine is going onto a 3inch front pipe then into a 3.5inch catback (all hks) so I wouldnt think the less than 5mm diameter that close in would make THAT much of a restriction on such a proven turbo?????? Seems to still be good for an easy 280rwkw and I think JoeyJoeJoe got over 300 on E85 so Im not worried.

Hope this helps, I have the whole kit still in the box inside its individual plastic bags so let me know if you need any other info

D

[Harey]

Hope this helps, I have the whole kit still in the box inside its individual plastic bags so let me know if you need any other info

D

Thanks Dave you are a legend! Sorry for the slow reply just got back from Japan.

The dump I have looks almost identical, yours looks like it has a 3rd pipe welded in but mine just has the 2 large pipes welded together.

Also mine reduces down to a 2.5" size at the flange.

The part that has me scratching my head is why would they funnel it down to 2.5"?? whats the point of having a big opening and funnelling it down to 2.5" and then expecting people to run 3" front pipes etc?? Surely the narrowest part of the exhaust is the restriction especially when its right near the front of the exhaust. I am thinking about getting an exhaust place to chop off the lower 2.5" part and join it with some 3" pipe so its never smaller then 3". What do you think?? It does seem to work fine without it (other results on this forum), it just seems strange. Even people with stock turbos try and keep the exhaust 3" turbo back!

Are you sure yours is 2.75" inches at the flange? If so, I think mine will need some modifications.

[Harey]

Also interesting how almost all brand name front pipes have a 2.5" or 2.75" start to them and then turn to 3".

[DaveO74]

Pretty sure on the size but I'll re measure it to double check, give us a couple of hours man and I'll get onto it

[DaveO74]

You were right to ask me to check again, 2.5" pipe BUT the actual flange is 2.75" and the pipe is kind of flush on one side and about 3-5mm short on the other.

At closer inspection Im a bit miffed with the quality of the dump pipe as a whole considering its a >3.5k kit. I mean the welds in general are outstanding but there are a lot of jagged edges which could do with a tidy up me thinks. I might have to get out the die grinder.

As with the welding on of a 3" flange and pipe i really dont know???? would it get us THAT much more flow for the hassle. As i said earlier HKS have put a heap of R&D into this particular turbo kit and I do wonder what the idea is behind the slightly smaller dump but do they know something we dont or am I trying to read too much into it????

Im no expert with turbos so Im really just guessing, maybe the 2.5 is cheaper and easier to mass produce???

Where is disco when you need him to answer the tough ones....hahaha

The wastegate part of the dump more than big enough IMO, I think its the biggest split dump Ive ever seen in that respect but I hear you about the other pipe. Im a little confused myself.

I might have a chat with my tuner and see what he reckons although when I told him i bought the pro s he did say I will not be dissapointed as they are a very worthy huffer for the 25

[Harey]

Thanks Dave no hurry.

Also just wondering what your logic is behind the dump pipe having a diameter of 2.75" and then using a 3.5" catback, sure it won't hurt anything but I don't see the point.

[DaveO74]

No logic really, had the catback for a few years now (HKS silent Hi-Power) and was running a highflow for ages so decided to upgrade the turbo and grabbed a front pipe to suit

[Harey]

Agreed the wastegate port size is excellent! It just seems strange to reduce it so quickly.

You can't have too big of an exhaust behind a turbo its just whether the extra hassle is worth it.

I know what you mean, hks got the turbo so right surely they can handle the respective dump pipe. Maybe I am putting too much thought into it, just want to do it once.

[Harey]

Yeah mine is the same 2.75" flange but the internal diameter is smaller, bout 67mm.

[joeyjoejoejuniorshabadoo]

I think JoeyJoeJoe got over 300 on E85 so Im not worried.

325

[Harey]

haha

what front pipe do you run joey?

[DaveO74]

I'm looking at it this way, as it is with the proper supporting mods we will get an easy 270-280rwkw right?

Add to that E85 or on my case I'm going to use water/meth injection, and 300-310+ rwkw is very easy to get.

At this point we are really going to be pushing the standard bottom end and our cars are not what you could call newish anymore (my 33 is in excellent condition but still has 100k on the clock) so I'm trying to avoid a built engine for as long as can as I want to do everything else first e.g brakes, suspension blah blah and it all cost a lot of coin.

~300 killer wasps makes for a scary fast street car I reckon and really any more than that in a rwd is sort of asking for trouble driving around in traffic and such.

Know what I mean???

[joeyjoejoejuniorshabadoo]

haha

what front pipe do you run joey?

apexi 3"

I'm looking at it this way, as it is with the proper supporting mods we will get an easy 270-280rwkw right?

Add to that E85 or on my case I'm going to use water/meth injection, and 300-310+ rwkw is very easy to get.

At this point we are really going to be pushing the standard bottom end and our cars are not what you could call newish anymore (my 33 is in excellent condition but still has 100k on the clock) so I'm trying to avoid a built engine for as long as can as I want to do everything else first e.g brakes, suspension blah blah and it all cost a lot of coin.

~300 killer wasps makes for a scary fast street car I reckon and really any more than that in a rwd is sort of asking for trouble driving around in traffic and such.

Know what I mean???

yeah, i run around at 280 with no worries, but on ethanol it's useless for the street, cold tyres, 8/6 coils and 325rwkw is just wheel spin territory

[Harey]

Is it this apex front pipe:

http://m.ebay.com.au/Pages/ViewItemPic.aspx?emvAD=320x411&aid=380277809380&emvcc=0

It looks to have a smaller diameter at the flange to the dump pipe.

[joeyjoejoejuniorshabadoo]

failed link mang

[Harey]

failed link mang

Woops I was trying to do it on my phone, try this one:

http://cgi.ebay.com.au/APEXi-GT-Spec-Front-pipe-Skyline-R33-ECR33-RB25DET-/380277810553?pt=AU_Car_Parts_Accessories&hash=item588a52e579

See how the top part is a reduced diameter.

I have pretty much decided just to use the dump pipe as is and buy a Blitz Front pipe. The provided dump pipe seems to work fine for everyone else.

[DaveO74]

It'll Still be a bloody fast car Harey 3" or not.

How long till you put it on? I'm still working with the interior at the moment so mine won't be on for a month or two.

Keen to see your results mate

[Harey]

It'll Still be a bloody fast car Harey 3" or not.

How long till you put it on? I'm still working with the interior at the moment so mine won't be on for a month or two.

Keen to see your results mate

A restrictive exhaust on a turbo car creates more lag and reduces top end so its just lose lose.

For the sake of a few hundred dollars spent on modifying the exhaust could net considerable gains, I dont know I would just love to know. But why would hks create these dump pipes and why would all the front pipe manufacturers start them off smaller than 3" and then increase them to 3".