Yes, true...but if I am not mistaken their system uses the hyperflow cats. On the other hand you also have a point, not having the bypass/valve path may not be allowable per smog rules. Anyone have any words?
Hey in the UK we dont have as much emmisins nonsense. So i will buy what ever is needed to give me a genuine 363 RW BHP like 355nuts car After the dyno posting of course
Ok then, i have been away for a while and am now catching up today. Ssoooo whats happening dude...pictures and Dyno sheets are......were........please, pretty please
I want u Harmony guys to know that I am actively looking for a 355, but I am holding off my purchase until I get your figures. My check book is doing cartwheels and I have to hide the pens.
Have not seen any significant precipitation for some time now . Average temps lately are about 70F, right Dave? You can't go wrong with a 355 Vince!!!
Ah, goth am looking for the right one, but I am pretty demanding. LF '95 GTB red/tan or red/black, 30K miles max (slightly flexible), valves done (must), headers repaired (at least once ). I will install Hyperflows, exhaust for starters, but whatever extras are on, I would probably take them. Then, of course, there's the harmony stuff... *drool, slurp* 363 RWHp! Hey this thing could actually be almost as fast as my 996TT!
FYI - If you keep insisting on valve guides made out of steel, as the post 1996 cars, you will never get to 363, or more,rwh. My valves are original, and after 13,000 miles, are just fine. In case any of them go, their replacements will be either the same or super light alloy as in F1 engines. Extreme performance goes hand in hand with wear. The 355's with steel guides are no match for the earlier cars.
I seriously doubt that the valve guide material will have a significant impact on HP. The biggest change from 95 to later years was from Motronic 2.7 to 5.2 and the different intake plumbing associated with this. There is a lot of speculation about the cause of valve guide problems, and one of the theories is that the headers burn through right at the first weld and thus don't expend the hot gasses as efficiently as they otherwise would, thus allowing the valve guide to get too hot - thus it dies. This is supported by the observation by some folk that valve guide problems are correlated to exhaust problems, with some time delay. It has also been noted that the M2.7 cars run richer than the 5.2s, and thus EGT is lower, and thus a lower likelihood of exhaust burn through. I don't recall hearing about the prevalance of valve guide issues on M2.7s compared to M5.2s however. Brian Crall and a few others will surely know this. One thing is certain - valve guide "problems" were not experienced on every car of a certain model year or configuration. And when the factory finally changed to steel, there was no loss in power. One request about the dyno charts.... can we please have before and after charts? Otherwise 363 RWHP is pretty meaningless blah blah blah. Dave
Not to be contentious, but drive a '95 and then drive a 97 or later, and then tell me there is negligible power difference. There are many who also think a spyder is as fast as a B which is anything but the case. Yes, the 2.7 vs the 5.2 is a contributing factor, but the valve guides also contribute to the differential. At the end of the day, it is a lot of little things that add up. Also, it seems to me that most of the valve guide complaints on this site have to do with the 2.7 not the 5.2, or did I misunderstand you? The final dyno run is scheduled for Wednesday - we did one more little tweek - after which the before and after charts, as well as many pictures of the interior and exterior will be posted.
Here is some valve guide material information: Tin Bronze ( North American UNS C90500, German CuSn10Zn, British G1) for piston airplane engines. Aluminum bronze (North American UNS C95400, German CuAI10Fe, British AB1) for high temperature applications. Aluminum Silicon Manganese Bronze for High Speed Engines.· Other alloys such as manganese bronze and leaded phosphor bronze have been used sporadically. Other alloys such as manganese bronze and leaded phosphor bronze have been used sporadically. Graded Cast Iron of 25 & 30 Grade. This Cast Iron is specially made for High Racing Engine.
I find this argument unconvincing. First, I am looking for a 1995 car with the steel guides, not a lower Hp 98+ with steel. I am very glad ur experience with bronze has been a good one. I do not want to chance it. I strongly believe that once u start pushing this engine up in output, whatever is weakest is going to fail - on early 355's that's guides and x manifolds. So, I want them done on the car I purchase. If not, then this will factor in my price becasue I have to do it. Personal preference. I also fully expect the same performance gains as u. The '95's are 2.7 cars and the intakes are dual, so there is all that potential compared to the 5.2 and single intake later models. The 95's escape the OBDCII restrictions. Changing guide material isn't going to effect a thing.
I am glad that we both have staked a position we are unwilling to change. However, I am willing to bet, whatever you choose, that you will not get the same horsepower gains as me.
The difference in output is between 2.7 and 5.2. There is no difference between a 5.2 with steel guides vs a 5.2 with bronze guides. Remember that only 95s have the 2.7. All other years have 5.2 in the US market. I believe that Europe and other regions retained the 2.7 for an extra year or 2, but am not sure. This would explain reports of different output for 97s. Regardless, I stand by my argument that valve guide material makes an immeasurable difference in output. At 20,000 rpm it might matter, but not at 8000. Now, has anyone dyno'ed a car before and after changing the valve guides alone, where there was no problem with the guides in the first place? Regardless of all this... waiting for before and after dyno charts, including before ANY mods were done to the car, and all on the same dyno of course.
I have a hard time believing that valve guide material will make any guageable horsepower difference. Tolerances between the guide and the valve may affect it slightly but not to the level of 328 RWHP to 363RWP. That is utterly ridiculous on any level!!! Another thing, we have yet to see any proof of your 363 RWHP...
And even if we see the dyno charts, we need some way of "calibrating" the dyno against a standard 355, hence the request for a pre-mod chart, or at the least, a chart of another stock 355 on the same dyno. It is unrealistic to compare different dynos, so we can at least hope to be able to compare different cars on the same dyno, where one of the cars is at least a (semi-)known quantity. Who knows, this dyno might show a healthy, stock 355 at 290 RWHP, in which case the 363 looks even better!
