srp

Yea, you can post it if you want. Post the 554 vs 492 run also, this will show how broad the power curve gets when the engine is laboring and is not allowed to peak at its natural resonance on the Shearer vs Sniper sheet, if you could overlay the run where the Sniper peaks at is natural resonance making peak power at 10200 would be good too. For the Sniper to be better on a 350, the engine should be tuned to make .23 horse-power per CC or be ran on methanol. Snipers may run very good on the little engines but they may not be the best for peak power on the dyno. On methanol RDZ says the Sniper will out perform all other in-frame pipes even on the little engines, we have not done that test yet on the little engines. Even on small engines where they do not make the most power, they may add performance by accelerating quicker.

When someone tells you they are bogging and wheeling up with 11 and 12 paddles at Little Sahara, then lose one race and then puts a 120 rider on it for the rest of the day, tells me all I need to know!

The design specs are for 197 exhaust duration and cylinder pressure of 100 atmospheres (a balance of timing and trapped compression). The dyno sheet shows the Sniper to have a broad power curve compared to the Shearer, that means its not peaking at its natural resonance. Being rich, too much timing, compression too high, not enough load and dynoing with a eddy brake can cause this, also gearing and mph on the dyno should simulate the mph as at the track and if two pipes peak at different rpm's, one should have gear added or subtracted to run close to the same mph, so they will have the same engine load. Mailman had some oof drag pipes and did not have time to tune them in, his bike was tuned in close for the Shearer pipe, so he ran them. Those pipes are in the dyno video with the silencers, they are on Brad Painter's bike now and he has won the first four races with them. After running Brad's engine, we realized that the 10 mill cubs are more efficient and are putting off more heat energy than we thought. Now we do not put any venturi or stuffer in the stingers of high output 465's on alcohol. Your Shearers have a 22.7 stuffer welded in the stinger and the Snipers has a 24.5 stuffer, this is one reason why the Sniper's run cooler than the Shearer's and needs less fuel to build heat. The exhaust duration of your engines should not be any problem, they have been tested on engines from 189 to 204 exhaust duration with very good results. The pipes would be a very good match for the 397, try them on that if you don't already have something that will break the record, it will have less intake volume and should be easier to tune with Lectrons.

Sniper pipes are designed to extract the elusive last 5 percent from engines capable of producing 41000 to 52000 joules per second. 397 to 465 cc engines fall in that range. On well built engines, power output of .245 to .25 horse-power per cc can be expected on gasoline, 8 percent more for methanol. Any 397's making less than 97 horse-power, or 421's making less than 104 horse-power, and 465's less than 114 on gas will benefit with Sniper pipes. Many of the top builders can produce these numbers easily with Sniper pipes. Most people know that Sniper use's resonance to boost power, but also and just as important the correct expansion rate is used. Heat energy output is calculated and the correct kh factor along with inter-median factors will allow the exhaust gases to cool without losing too much velocity. We build low kh factor pipes designed for the highest output engines. High kh factor pipes are more common because the have a wider window of engines they will run decent on. Low kh factor pipes will need good porting to run to their potential. High kh pipes will have the header and first two diffusers choked down and will have aggressive third and fourth diffusers, like a 18 to 20 degree last diffuser, the low kh pipes will expand the gasses earlier in the header and first diffusers, with only a 14 to 16 degree last diffuser for smooth expansion.

Matt and I waited until the sun went down on Saturday to try and get our match race in. He wanted to race as bad as I did, we both have something to prove. He did say Cam out ran the 4 mill cub I was going to race but had trouble keeping his bike from flipping over. Maybe there needs to be a rematch there next year? Sorry the race did not happen, we were 100 percent ready on the day of the race but the rain never stoped. I suggested we meet at a drag strip like Planetsand or somewhere. So the race may still happen.

Passion can deck it, he decks every Cub he builds to get the excessive durations down.

Its good to know there are builders out there that will build to the owners needs and not just do the one size fits all.

The idle kit will allow adjustment of the idle air / fuel ratio and just off idle, it will not effect high Rpm's where the power-jet comes in. The Lectron carb metering rod will only stop in four slots when adjusting. The idle screw will allow adjustment anywhere between the four slots, giving fine tuning ability for idle quality. This will allow the metering rod to be adjusted for mid-range performance to be crisp and clean, without having to supply the correct air / fuel ratio at idle. Sometimes when the metering rod is tuned to come on the pipe clean, the slide screws will not raise the slide far enough for a quality idle. This is another time when the idle circuit really helps because it will meter fresh air coming in through the choke horn that it normally would not have to blend out the idle We have been modifying all of our Lectron carb's with this kit for over 20 years. Adding this kit to carb's that are already tuned in will allow for even finer tuning of the idle and mid-range.

Sniper Racing Products has designed a simple idle circuit kit that will allow adjustment of the idle air / fuel ratio on Lectron carburetors without having to move the metering rod or idle slide screw. The kit simplifies tuning Lectron carburetors by 100%. Normally, the correct tapered metering rod has to be adjusted to within 1/4 turn for optimum performance. With the newly designed Sniper Racing kit, it will only have to be within two turns. Then, it can be adjusted in with the idle screw. The kit will include screws, springs, drill bits, a tap and instructions for easy installation. Kit installs by simply drilling two different size holes in the carburetor body (using supplied drill bits) and then using the supplied tap to cut threads in the carburetor body. Many people know Lectron carbs are very temperamental to tune in. Therefore, Sniper Racing Products has now simplified the tuning process. 1 carb setup- ($32) 2 carb setup- ($42) *Free-Shipping Included* ******Sniper Racing can install kits for a small fee. $25 per carb****** If you are interested in one of these new kits please PM me! Links to Pics are below. pic 1 pic 2 pic 3 pic 4 pic 5 pic 6

If the pulses on the dyno was changed 1 pulse it would read the same peaking Rpm as the Dynojets. Then the overlay would look totally different.

Bodiddly did the complete BBSFOOF and SBSFOOF Shearer test. He dynoed twice and went to Atoka. (421 cub on methanol) first test was geared for racing at 15/41,the BBSFOOF 91.0, SBSFOOF 98.0.The big split there is from the piece of tubing welded up inside the SBSFOOF's chocking it down to 22.7mm building heat faster while the big bores are 26.4mm. Second test was re geared to17 or 18/41, both pipes hit close to 113. At the track in Atoka both pipes ran about the same et. On a 397 the SBSFOOF Shearer should be faster than the BBSFOOF Shearer. It will like the choked down stinger.

We will be testing on a 350 next week, it has been ported by Sandtrax in Tulsa. It has small carbs, factory air box and currently runs T4's and is well known in our area for being a good tuned and fast bike.

Sniper Racing Products is happy to announce our first promotional set of the new mathematically designed In-frame Assassins which are currently for sale on Ebay Auction. This is a true auction with NO RESERVE!!! The auction will last for 3 days only, ending on Sat. In the past, pipe builders have promised performance gains and did not deliver. Therefore, Sniper Racing is offering a complete performance guarantee with these promotional pipes on engines from 392-485 cc displacement.. If these pipes do not out perform your current product, just send the pipes back within 30 days from delivery for a full money refund. This auction is for one complete bare metal exhaust system setup including polished silencers. Please see Ebay auction for more details.... Ebay link below... Sniper Racing would like to thank all of those who have supported our efforts in bringing new technology to the sport of Banshee racing!! -Sniper Racing Products http://cgi.ebay.com/ebaymotors/Banshee-Sniper-Frame-Assassin-Drag-Pipes-_W0QQcmdZViewItemQQhashZitem1e60c09329QQitemZ130472252201QQptZMotorsQ5fATVQ5fPartsQ5fAccessories

Excellent, Thanks for the data sheet.

Andy, What are the exact port durations on the 421? Banshee or Blaster style pistons?

ETA is about thirty days for the In-frames. There are pieces to the silencers that are not here yet to have a clear picture of cost. I'm not sure if Jim will post any more dyno sheets being so close to them being ready. What we want to see is real world feed back from the track. I do think we are going to dyno a hard running Fast Racing stock cylinder 4 mill. If we do I'm pretty sure it will get posted.

If they are inframes I have seen the CPIs shine with alcohol. May be so close you will need to dyno or run it on the clock.

The scientific standard is calculated in bars (9 bmep low) (11bmep high). Your formula divided by 14.7 will convert to bars. The 492 is somewhere around 8.85 bmep. If a 492 is tuned to 11 bmep@10700 it would make 131 horse-power. This shows more tuning can be done to extract more power. The engine in my drag bike is a 10.88 bmep Passion 421 Cub on gas making 105 horse-power@10150. This shows my engine is very close to maximum output. By your comments you seem to be knowledgeable and on your game. The first number I look at when rating an engine is bmep and then horse-power second.

BMEP is brake mean effective pressure. It is a way to calculate potential engine horse-power before the engine is actually built and will tell you if an existing motor is putting out maximum horse-power. A well built 2 stroke on gas will be around 11 bmep and on alcohol can be close to 13 bmep. The equation for for two stroke bmep is 75.4*torque(lb-ft)/displacement(Ci)/14.7

Projected heat and flange inside diameter will dictate the angles and body diameter of a correctly designed pipe. A high Bmep 421 and a low Bmep 510 will take a similar pipe. On engines such as a high Bmep 510 Cheetah will need a bigger stinger to bleed of heat . Sniper will offer this type of mod for big bore and hill shooting, both needing to bleed of heat to combat power fade. We dynoed with the small bore small flange out of frames Mailman was talking about on 6/3/2010. The inframe Assassins dynoed 5hp stronger with 2 more foot pounds of torque on a 421 cub.

We are looking at removable silencers for the OOF. I have removable stingers on most of the OOF drag pipes. Being able to change the stinger diameter and length at the track will help combat power fade in high gear.

The stingers welded to the the expansion chamber will have a 18 degree mandrel bend so they will hug the frame and clear the air box and filters. Then the tail pipes will slide straight on to them.

Lonnie and Ed both liked the output of the in-frame Assassins. Ed did all of the tuning on the engine when the pipes were switched out to keep the air/fuel ratios the same. Ed and Lonnie both give me some good info on silencer design too.

Maybe Andy can get everybody together after that new track opens up. We enjoyed coming to old Nowata track and don't think we missed even one race. We have not been out in almost a year. There is just no where to go around here. Is meeting up at Whitefield OK for some hand flag races too far for everybody? Going to a all day test and tune somewhere would be better. If everybody got together and wanted to race at Extreme world, Maybe David would open the track for that but last time he had a race there were only three racers that showed up. So everybody can see why it is closed.

We just had a window of one hour on Saturday. If we would have had more dyno time we would have changed pipes and tuned. We mainly wanted a base line on alcohol. We will go to the track for testing. Our drag strip in Tulsa is closed all of this year. To test three sets of pipes and tune all of them on gas and alcohol is going to take more runs than we will be able to make on one Friday session at Atoka. What about Mooreland? When will they test & tune again? If there is a more known dyno shop than Santrax's close to us somebody will need to tell us where it is. Two really big builders know them and has use them many times being Mccoy and Andy. They could probably tell you more about them than I could. We would like to go to another dyno for a second opinion to validate our pipes. We have dynoed many times on Fastracks Dynostar with all of the prototypes with virtually the same results but he is just now getting his name out there and is not well known yet. By looking at the temperature and humidity, the run conditions were better on the day of the gas test. One thing the correction factor don't do is compensate for the water grains in the air and it was bad on Saturday. 99 on Saturday with a density altitude of 3,546 and 61 and 2,755 density altitude on the Thursday that we did the gas runs. The true correction factor on Saturday was actually 109.1 and not 106. We did not really give the alcohol test a fair chance not raising the compression and adding some timing but we will do it again.