Author Topic: Big bore stinger project (Read 13160 times)

rsss396 · « **Reply #15 on:** October 27, 2013, 05:48:49 PM »

I have been saying that all along, if your 370 runs good with a 1-1/8 o.d. then your setup is not making big power, but there is no guarantee going to a bigger stinger will mean you will make more power if it is a mild setup or the wrong setup to begin with.

Jerry Hall · « **Reply #16 on:** October 27, 2013, 06:39:41 PM »

May I add a few words to your statement?

Quote from: rsss396;15884

I have been saying that all along, if your 370 runs good with a 1-1/8 o.d and is not showing signs of piston crown overheating then your setup is not making big power, but there is no guarantee going to a bigger stinger will mean you will make more power if it is a mild setup or the wrong setup to begin with.

A pipe that is slightly over-restricted will usually make good peak power and have good over-rev. Many of the drag engines that I have dynoed have pipes that are over-restricted. I not sure if over-restricting is the result of a lack of understanding on the part of the pipe builder/designer, using improper testing procedures/equipment on the dyno or just laziness and failing to spend the necessary time getting ALL of the pipe dimensions to work with the correct back pressure.

rsss396 · « **Reply #17 on:** October 27, 2013, 08:56:50 PM »

I am not sure if its my setups but every time I try to run a restricted stinger I made less power on the dyno, I had that problem on my oem cr500(553cc) cylinder and my Liger cylinder(613cc) both made more HP with a 1-3/8 O.D. over a 1-1/4 o.d.
The Liger detonated like crazy no matter how much fuel or compression I took out of it.

Bowtie316 · « **Reply #18 on:** October 28, 2013, 10:56:22 AM »

Had a chance to further test mine out yesterday, and honestly if it lost anything anywhere with the stinger mod, I couldn't tell. I didn't even change jetting and it still felt perfect. I got to race a stock cylinder 250r and a piped yfz and I pulled both of them pretty handily. Bottom end is definitely improved, this was a surprise. Top end pulls like mad. I want to try out a little higher gearing now.

Can't wait to get it in the sand.

Wes350x · « **Reply #19 on:** October 28, 2013, 10:59:51 AM »

Nice to hear. Glad you sound happy with the motor!

Bowtie316 · « **Reply #20 on:** October 28, 2013, 11:14:34 AM »

Quote from: Wes350x;15948

Nice to hear. Glad you sound happy with the motor!

Yeah Wes, Thanks. Everything worked out, I was pretty nervous about it for a while but it's all good. It certainly does run strong. I was kind of reluctant to race the yfz considering all the money I spent and I didn't really set it up like it should have been with the pipe and carb size, but it ran really good. Even if I lifted the front on takeoff, I could regroup and pull him in pretty easily. Now this 450 was just bought by my buddy and might not be 100%, but nonetheless it pulls much better than before. It's going to be perfect in the sand.

Jerry Hall · « **Reply #21 on:** October 28, 2013, 01:54:47 PM »

Quote from: rsss396;15906

I am not sure if its my setups but every time I try to run a restricted stinger I made less power on the dyno, I had that problem on my oem cr500(553cc) cylinder and my Liger cylinder(613cc) both made more HP with a 1-3/8 O.D. over a 1-1/4 o.d.
The Liger detonated like crazy no matter how much fuel or compression I took out of it.

It depends on how well your stinger/silencer combination flows. I start seeing "the too much restriction syndrome" on some engines making 60 hp on 1 1/4 OD 18 ga. stingers. I seldom use 1 1/4 OD 18 ga. stingers on any big bore single cylinders that make over 80 HP to the rear wheels on my chassis dyno.

I encountering "the too much restriction syndrome" on some big bore single cylinder engines that are only making around 75 RWHP when using 1 3/8 OD 18 ga. stingers.

If I remember correctly your Liger was making around 100HP. You may be on the threshold on needing to go larger than 1.277" ID stinger. Give the engine what it wants, not what some pipe formula for a small bore roadracing said was optimum. Remember there is more mass in the exhaust that has to flow past a given plain in the exhaust system when using alcohol than when using gasoline making the same HP.

rsss396 · « **Reply #22 on:** October 28, 2013, 03:42:58 PM »

Thanks Jerry, I have thought of trying some 1.5" stingers with restrictors added to it in the future. I last dyno'd at 110hp so it's maybe time to move up to the next size.

udontknowme · « **Reply #23 on:** November 24, 2013, 02:02:15 AM »

just noticed this the other day. not sure if its owrth a crap or not http://cpiracing.com/shop/index.php?route=product/product&path=63&product_id=503

Pumashine · « **Reply #24 on:** November 24, 2013, 08:02:16 AM »

Quote from: udontknowme;18224

just noticed this the other day. not sure if its owrth a crap or not http://cpiracing.com/shop/index.php?route=product/product&path=63&product_id=503

Wow, that mid section is huge. Wonder why it has 2 nineties at the stinger? I know one guy using this one and he had to have it modified to fit at a local shop. Price is good but you will probably have to fit.

etccb · « **Reply #25 on:** November 24, 2013, 11:44:49 AM »

"just noticed this the other day. not sure if its owrth a crap or not http://cpiracing.com/shop/index.php?...product_id=503"

That stinger flow is insane. I am shocked at what I am looking at. Different.....

Hawaiiysr · « **Reply #26 on:** November 24, 2013, 12:14:19 PM »

Flow? Did a plumber do the pipe fitting? Cause it sure looks like he installed a p-trap

Pumashine · « **Reply #27 on:** November 24, 2013, 12:15:59 PM »

Quote from: etccb;18238

That stinger flow is insane. I am shocked at what I am looking at. Different.....

Yeah. maybe goes above the seat or something. Looks like the turn down on the muffler is on the wrong side

C-Leigh Racing · « **Reply #28 on:** November 24, 2013, 12:35:35 PM »

What Jerry said in one of his replys sounds good to me, with a larger stinger you can use larger jets.
So in turn, more fuel mix will be flowing through the engine, which will make it last longer. I'm all about having big HP, but want the engine to last longer than normal, blow those ol nay sayers out of the water saying a 2 stroke wont last any time.
Neil

Bowtie316 · « **Reply #29 on:** August 05, 2014, 10:22:04 AM »

I just thought I would update this thread to say that by buddy [MENTION=904]RED RIDER[/MENTION] put this pipe on his trx9 port ESR 310, it seemed to lower coolant temperatures and it seems to run the same or a little bit better. No drawbacks whatsoever, he ended up converting his own trx5 pipe to big bore as well.