Fed. down pipe

[nsr250]

Billy,

Any idea when you'll have these sorted out and at what cost? I'd like to eventually get my hands on one.

Don

[Elanlover]

Thanks Billy, wasn't sure if the reference car had the PCE on it or not. I'm concerned that, after the modifications, the car seems to run rich. Alan spent a lot of time reviewing and testing the maps in the car's programming to ensure his chips were optimal. I'd like him to comment on what you've found after your mods and why you're seeing that (I'll notify him of this topic). If its true, and if there's a production run on your parts planned with enough pepole interested, he may be convinced to create some suitable programming for this mod.

All in all it seems that a combodownpipe/PCE replacement needs to be purchased and installed as well as ceramic coating the new piece, exhaust manifold and the exhaust side of the turbo housing. Were there other mods involved such as moving the rad or a/c components?

[surfboardfiller]

Small update:
The ID of Steve's exhaust system is 2.25", so this V2.0 is finished in 2.25" pipe, with 1.5" for the wastegate. By request in the future, we will be making them with 2.5" outlets and could probably even figure out a way to go 3" if someone had a need.

We will be adding the bracket for the support mount. And the wastegate discharge pipe is isolated with a flex bellows so it will not crack.

The exhaust bits for Steve's project are ready to go off to Swain for White Lightning coating. Inside and out on KnoxStiffy V2.0, outside on manifold and turbine housing, which are both ported.

At the track day at the end of a run, the oxygen sensor bung on the stock downpipe was 849*F the turbo center section 220*F. Compressor housing 125*F with 87*F and 99* track. We'll consider that a baseline to shoot for in terms of overall temperature reduction with our Stiffy.

Does the waste pipe need to be so long? If it were shorter then wouldn't it be lighter and more efficient?

Shouldn't the oxygen sensor be where all exhaust gass flows through the system, not just the charger gasses but the waste too?

I am liking this but like to understand the design more.
Cheers,

Phil

[steve matthews]

Phil, Billy may correct me but I believe that the further away the wastegate line
enters the main exhaust flow the better the result. The 18" figure sticks in my head.
We did not have the 18" so it is where it is. Weight I do not think matters on this
small a pipe. OT sensor position could be moved but would require a longer plug.
Exhaust gases being different from main exhaust to wastegate exhaust I can't
answer that but I would think not.
Steve

[knoxmotorsports]

Don, we are working on getting materials in order for a production run. We will probably do the first run or two in group-buy format, as it is easier to do a lot of them at once than one every few weeks when an order rolls in. Cost is still TBD but trying to keep it affordable.

Elanlover, even before our downpipe, the everest tune was excessively rich while in boost. I know it is safe, and I'm cool with that from a liability standpoint, but there is a lot of power and torque on the table from the afrs being in the 10:1 range. It is probably not cost effective to do a stiffy-spec tune, but if ESM wants to, by all means. In general, the fact that the same tune is now ~1pt leaner across the board while in boost leads me to believe that the whole system as a unit is working more efficiently (more air is now allowed out through the exhaust, enabling a more thorough burn event) and that the ESM tune may be fine, but given certain restrictions in the system, it is not able to realize its full potential.

You can do the downpipe by itself or the whole package. We had the turbo and manifold from Steve's wrecked M100, so it was a no brainer to port the manifold and turbine housing while they were off the car. We chose to swain tech the whole shebang because they were off the car and it wouldn't force the car to be stuck on jackstands or anything. Also, a few of the heat shields are eliminated with our downpipe, so we wanted to keep heat under control.

The turbo is packaged in the bay tightly, removal is difficult/tedious. We are working on streamlining install directions and tips to make the job simpler.

Wastegate tube length has to do mostly with allowing the gases to cool sufficiently such that they do not disrupt primary turbine flow when they are reintroduced. There is an "ideal" length given several engine variables, but in general, 12-18" is sufficient. I think we came up with The better the flow relationship between the turbine and the wastegate, the more effectively the turbine can do its job. This is why we see more power with less boost, the turbo is working more efficiently.

As for O2 sensor placement, we put it there because that is the stock location, as bolt-on parts purchasers do not generally like to cut and splice/extend wires, especially for critical engine sensors. It doesn't make a difference if it is sampling from the entire system or solely from the turbine discharge, as the content of O2 present does not change as it flows through the turbo and manifold. It changes in the combustion chamber, from a more or less complete burn, more or less timing, etc.

I really think a tubular manifold would be trick. If the stock downpipe is any indication, the gains ought to be impressive as well. Packaging is the issue. The stock manifold is pancaked so thin that the gases have to make 2 complete 90* turns before exiting through a teeeeeeeeny little hole and into the turbine.

[ashm]

I took some measurements with a tubular manifold in mind, and gave up after seeing how tightly the stock unit is packed in there! I'm sure it can be done, but there's really not much room to play with.
Adam

[racerstev]

I think you will find that the manifold is not a problem with a turbo this small. There can be huge gains after
the turbo like you are finding but very little before. I plan on logging backpressure before the turbo on
mine this year, I'm betting on a 2 to1 ratio boost vs backpressure. So 10 pounds of boost and 20 pounds
of backpressure.

Steve

[surfboardfiller]

...

As for O2 sensor placement, we put it there because that is the stock location, as bolt-on parts purchasers do not generally like to cut and splice/extend wires, especially for critical engine sensors. It doesn't make a difference if it is sampling from the entire system or solely from the turbine discharge, as the content of O2 present does not change as it flows through the turbo and manifold. It changes in the combustion chamber, from a more or less complete burn, more or less timing, etc.
.....

I was thinking the O2 sensor would only be sampling exhaust gas when the waste gate was closed. But I realise now the exhaust gas still flows through the turbine when the waste gate is open, its just at a reduced rate.

Thanks for your replies.

Phil

[knoxmotorsports]

I think you will find that the manifold is not a problem with a turbo this small. There can be huge gains after
the turbo like you are finding but very little before. I plan on logging backpressure before the turbo on
mine this year, I'm betting on a 2 to1 ratio boost vs backpressure. So 10 pounds of boost and 20 pounds
of backpressure.

Steve

great point, Steve!
EBR plays a huge role in the peppiness of the turbo setup, and also of how much power can be made and how long the power can be sustained.
Ideally, we'd have the EBR at 1:1 or even less (yeah, right). That makes for a very efficient setup.

Billy

[surfboardfiller]

I love the idea of a custom down pipe and was pointed to this thread when I mentioned my need else where on the forum.
I have opened a dialogue with Piper exhausts who are intertested in looking at making a down pipe for us in the UK. I hope that doesn't tread on anyones toes?
Let me know what you think.

Cheers,

Phil

[GeoffSmith]

Phil, there may be different issues to the KnoxMotorSport's masterpiece on RHD cars without the front crash structure, so a UK equivalent would probably have to end up slightly different.

If Phil can get Piper interested, would you be willing to help in getting it off the ground Billy?

[surfboardfiller]

I don't want to hijack this thread so I'll reply on my group buy thread.

[knoxmotorsports]

Phil, there may be different issues to the KnoxMotorSport's masterpiece on RHD cars without the front crash structure, so a UK equivalent would probably have to end up slightly different.

If Phil can get Piper interested, would you be willing to help in getting it off the ground Billy?

I do not think there is much front crash structure actually in the engine bay. Sure, there is that little bracket that makes the bumper contact the engine in a big hit, but it is still functional on Steve's car and not in the way in terms of our fitup.

I would be willing to help in any way possible, and i have posted in the GB thread already as well. I do not want to repeat myself, but I don't think piper will end up making the pipe at all (they would have done it years ago if it was beneficial for them). I may be wrong, but I am not sure why we need yet another stiffy on the market, when ours is already made and working very well. We do these projects to satisfy you guys, so it boggles me a bit when someone wants to go and have a large manufacturer make one rather than my small business. They are going to want to do a minimum order of ~50 units, which will not happen on here. They sure won't be stocking many for these now 16-21 year old beauties. That means we (collectively) have to foot the bill for their development. Our development is done already. Why squander?

[superbad]

I'm in for one of these whenever you guys are ready to build more.

[steve matthews]

Steve

[ccb056]

Sorry to resurrect a 1 yr old thread but I did some searching and couldn't find anything.

Are these downpipes available for purchase?

[trig]

Sorry to resurrect a 1 yr old thread but I did some searching and couldn't find anything.

Are these downpipes available for purchase?

Try here viewtopic.php?f=85&t=20961

I would love one but the price is to much for me