Viper TIMING spike, Need INFO!

[auji700triple]

HEllo All,

I am Very cerious about what happens to make the thing Run Hot at 8,400RPMS.. What happens? Is it Detionation? or just Jumping it Lean, i aM not Sure why this happens to vipers on 8,400 rpms, i just know it will burn your *** down but i dont know what causes the burn down? can someone Please shed light on this Thread cuz right now im lost on how the timing spike effects it. This Is for the VIPER timing Spike by the way, thanks alot guys!

 

[vipertripplexxx]

Vipers have about 8 degrees more timming than an SRX @ 8000 RPM. Thats a boatload of timming! They are able to do this because of lower compression, and less efficent filling of the cylinders due to the single pipe. At 8400 Rpm it's around 5 degrees more than an SRX, the advantage to viper box is that it alows the engine to run up past 8700, unlike the SRX box. Thus you must run richer jetting to keep the cylinders cool and prevent detonation. This is why piped vipers get such crappy mileage.

 

[vipertripplexxx]

If you have pipes like benders, that run at a lower RPM, then it may be advantagous to try running an SRX CDI. I believe that only an 02 box will work. Betheviper has posted some info on the temp sensor mod, or I can help if you need details. He originally posted that an 01 SRX box will work, but in the 01 schematics are different than the box he sold me, so I'm assuming that it's a late model 01, or 02 box.

 

[mrviper700]

viper timing/ srx timing

Some of the information below is correct, but the 01 srx box is what you use for a 02/03 viper swap, and the 02 srx box has dcs and wont work, that is unless you have a 04 viper.

The viper has MORE compression then a srx, only the pto cylinder has less, this was only done so you could jet the mains straight across the board, they(yamaha) thought that was a big deal for the consumer.

The reason piped vipers get such crappy mileage is due to the pipe design of the aftermarket. It is the pipe design which dictates how much fuel is needed as the pulse returned to the cylinder is of a differnt frequency then that of a srx, its a completely differnt length headpipe and overall length. A typical srx uses a 40-42.5 pilot, you need a minimum of a 47.5 pilot in any aftermarket viper pipe and the needles usually need to be raised, this is where all your gas mileage goes, you are 80-90 percent of the time trail riding on the low and mid range circuit, its not the mains which drink all the fuel. If you stick a cloth tape measure on a srx pipe from the piston side of the exh port till the silencer youll get one measurment, and when you do any typical viper pipe youll get a much shorter measurement, thats because a viper pipe needs to be a shorter length to rev at a higher rpm, a long pipe builds torq, and is a lower rpm pipe, the short ones builds higher rpm h/p, it can also build torq to a extent but it depends on the rear cone and stinger diameter, pipe design is another conversation all together. The viper exh port alone is only half as long as a stock srx is. The timing in a viper was needed to get the engine/single pipe combo to perform, when you add triple pipes you free up alot of power and advanced timing is not needed as much , however, more timing gets you better accelaration, and builds torq at a faster rate then retarded timing does, BUT, retarded timing pulls better topend then advanced does. Advanced timing puts more heat in the piston crown and beginning of the pipe, retarded timing puts more heat out in the pipe. This is also PART of the reason you need more fuel in the low/mid range circuit, to help cool the piston crown.

 

[vipertripplexxx]

The viper has MORE compression then a srx, only the pto cylinder has less

Nope, if you think just because the chambers are smaller and the displacement is equal, the compression is higher, you would be wrong. The higher exhaust port on the viper cylinders lowers the compression, thus readings of 135 cranking comp, compared to the srx which is about 140. not much but still slightly lower.

The reason piped vipers get such crappy mileage is due to the pipe design of the aftermarket. It is the pipe design which dictates how much fuel is needed as the pulse returned to the cylinder is of a differnt frequency then that of a srx

Bottom line... timing and pipe design both affect needed fuel flow. In the case of the viper, timing is the biggest issue. If you could reduce the midrange timing, you could run alot leaner needle jetting, and mileage would be alot better, even with aftermarket pipes. Go ahead and run srx pipes, and jetting with a viper CDI and see what you get.... a pile of aluminun

I figured the job would be easier with srx topend to start with plus better cooling and striaight timing on all 3 cylinders.

I was bitting my lip on this one, but since your nit-picking my posts I thought I would chime in. The viper box does have the same timing on all cylinders.

 

[mrviper700]

Put down the crack pipe again

LOL, you have got more untruthfull statements then G.W. BUSH!!!!!! nit picking your post??, nope, I was correcting your mistakes!!!! LMAO, before you go shooting off at the finger you really should do some research. I am not going to argue with you my points they are true and valid, or I simply would not post them, so here you go, this is not me but yamaha fact, not vipertriplexxx fantasy facts.

Please refer to page 2-52 of the 2002 yamaha tech update book, notice the compression ratio in which yamaha states for the viper and the srx, Now I know YOU THINK you know everything, but you may want to inform yamaha that they dont know what they are doing....

As far as putting srx pipes on a viper, never did it, never needed to, so I have no idea where you say I would have a pile of aluminum from doing it with this and that viper cdi box. I am the one telling people to change to a 01 srx cdi box, and there again your wrong on that information as well!



Have a nice day............>>>>>>>>>

.

 

[mrviper700]

cranking compression

I forgot to add when ya are doing a cranking compression check, you could raise the exh port 3 mm and it wouldnt matter, the exh valve is closed, so exactly how are ya going to get a lower reading there?? running compression, yes, it would be lower, maybe you forgot that.

ya got your numbers backwards there.............

In closing, I dont bash anyone on here, never did. I will however correct your mistake if you post one, for the benefit of the other guy who takes the information and put it to use. I dont go looking for your post, they are not important to me. I dont have the ego problem, you seem too.
So you can quote and post what ever, I dont really care. I come on here to help people . Kinda enjoy getting to know people with yamahas and helping to get them to run well.

 

[Junior]

AJ: I'll call you over the weekend.

the other 2 of you, no trouble on here, from what I've read noone has lied yet, compression RATIO is higher on the viper, but in my experience compression # is lower, valve is closed you'll argue, well there's still a volume to fill above it. he's running an 05 mountain viper, so he'll need an 02 SRX box if he wants to keep his DCS (which I would certainly imagine he would)

in short, both of you need to layoff each other, and if you wanna be taken seriosly mrviper, you're gonna have to stop editing your posts an hour after they're made.

 

[mrviper700]

I think the edit button is there to edit a post, I dont recall seeing a time lapse on it???, if I want to fix mis spelled words or fix my punctuation, I think I can do that, do you have a problem with that??? , then please ask Tom to tell me I cant fix things wrong on a post.

Junior, I dont think I am worried if you think I am taken seriously, we both know who has a little bit more experience.

 

[vipertripplexxx]

compression ratio

700, I know that yamaha says 6.7 ratio for the viper, and 6.5 for the SRX, but I think they might be using the powervalve bottom as a reference? I have done no calculations, I just don't know why they crank different on a gauge? Also if you take out the powervalves and do a comp check you WILL get the same compression reading, your not getting ANY ring seal on those powervalves! They simply restrict flow of gasses at higher RPM's.
As for the 01 box, thankyou for letting us know the facts, I have a PDF version of the manual, and it says it's for a 00-01, but it's 8DN-28197-10, thats only for a 2000, i know that now.

I dont have the ego problem, you seem too.

Please don't make this personal.
Ask BTV he will tell you running the viper box, you will need more jetting, or it's toast. So yes, any pipe that fills the cylinder better at 8000 Rpm will be better off with a SRX box, unless your using racing fuel. I just don't see the pipes as the problem, timing is the issue.

vipertriplexxx fantasy facts.

Just posting what I believe to be good info, what you added about piston heats and stuff, great stuff thanks.

 

[skidooboy]

everyone here has good info to add to help the asked question, please dont make personal attacks on one another or we may be forced to close or edit threads. or worst case give temp vacations to those that cant get along.

verify your info and post to help the person requesting help, and play nice is all i ask. ski