DSP to SM build

[Camaro5690]

the trick to welding gas tanks is filling it to the top with water first to displace all fumes.

[DSPXR4ti]

I just back from the Oakland SCCA event. I don't know what's going with the SCCA events lately but they are just all fast events now, very sad. I like technical type courses, oh well what are you going to do.

XR worked great, Oakland is asphalt surface so my XR doesn't work there as well as concrete, 2 clicks of rebound and 2 clicks of compression and BAM! my first win this year, yes you heard it right my first win for the year. It's ok because all the work is slowly paying off, with the miss fire at first and little thing after that going wrong this was a big pay off.

XR 37.304, EVO 37.314, EVO 37.784, EVO37.912 slowly moving forward. Next course at Crow landing is said to be a 90 sec course.

Now it's the little thing from here on end.

Changing out the right rear shock; Raised the XR today and the R/R drop faster then the left rear, check the settings, the same on both shocks, has something gone wrong with it. Send it in to get rebuilt.

Change the battery out the super light one, have the spare battery to help with start ups.

Lower the rear of the XR an 1/2 in, was very fast in the slaloms so don't want to change to much.

Clean air filter.

Does any know someone with a 32 mm front sway bar or has one that I may use, that I could try, will pay you for your troubles, Mike Maier said it would help with the over steer in my car but I told him that I had the biggest sway bar made, I don't know at this time of the year messing around with a sway bar change would be a good idea.

Lots of little things to do to be prepared for the National's, can't wait.

Ben

[catapultkid]

Congrats Ben! How did the new fuel tank fair? Notice anything?

[DSPXR4ti]

Congrats Ben! How did the new fuel tank fair? Notice anything?

It's ok, moves around a little bit but not much didn't have time to corner balance my car before this weekends event but the low speed right hand turn at Oakland, where the right rear wheel would usual have wheel spin on the Oakland surface but holding 35 lbs of gas right over the right tire help I believe but with the bigger gas tank is how I balance the XR by adding 5 gal more of gas, ask Chris Grayson about that some day or the next time we talk I'll tell you the story.
It only shaved 10 lbs off the rear of the XR, I know 10 lbs is 10 lbs but until I get the Rapido aluminum head W/stock valves it's not going make or break me/the XR.

Ben

[RatFink]

Hi Ben, I was just poking around here and saw this. On the topic of sway bars, I was under the impression the Bondurant cars had some ridiculously large diameter bars under them. Of course, hens teeth, but supposedly there was a guy not too far from me with one.

[DSPXR4ti]

Hi Ben, I was just poking around here and saw this. On the topic of sway bars, I was under the impression the Bondurant cars had some ridiculously large diameter bars under them. Of course, hens teeth, but supposedly there was a guy not too far from me with one.

Can you talk to him and ask, it would be interesting to try.

Ben

[DSPXR4ti]

So The thing I've talked about was how my engine is working right now, over the years I've heard about big valve engines are the way to go but like everything you do to a motor, there's a gray area in just adding a big valve head. I'm running a small valve, slightly ported, 1.1 cam head right now with good luck, now we had an event this weekend that had a 330 foot straight and what lead on to that straight was a 180 foot OD sweeping turn, now base on data I was already doing 30 mph a reached 65 mph, now of course your only really going about 230 to 250 feet before you have to hit the brakes but the greatest thing I did was adjust the cam and was able to get to 68 mph and back that up with a 67.8 and felt like it pulled all the way down to straight.

My question to you all would a 1.59 exhaust valve head be faster then a big valve head, would the 1.59 head have better torque wise out of the turn and in turn go faster down the straight. My feeling is the big valve will lose low end torque but have great gains on the top end, does anyone have tried this with some real data.

Ben

[catapultkid]

Personal option. Small valve head will have a optimum torque value which may be lower, in the rpm range, than a big valve head. This comes from the basics in runner size and length on any motor. However under your circumstance at 68 mph you're in boost and that means you need flow to create more HPs. So higher flow, with bigger valves and a proper cam should result in better straight line speed.

Now the question I would ask next is where does the bigger valve head flow better, is it due to extreme valve size or the porting where the cast iron head seems to neck down behind the valve?

[DSPXR4ti]

Now the question I would ask next is where does the bigger valve head flow better, is it due to extreme valve size or the porting where the cast iron head seems to neck down behind the valve?

Well that's what Bo did for me the 2nd time around, I love this head but just thinking out loud on the 1.59 head and big valve head, when doing searches and from talking to my engine guy, that the big valve head would work the best, his solutions was to turn up the boost, what do you think about that?

Ben

[DSPXR4ti]

OK so some new shiny bits someone ask for sometime ago, So a new lighter rear rotors by 4 lbs With 1 lbs lighter flanges a total of 5 lbs of unsprung weight, I wish I knew how to calculate rotating mass. Ebay stuff.



Top rotor is a 11.75 x .81 and is just 7 lbs

The bottom rotor is a 11.75 x .35 and is 3 lbs 11 oz

Ben

[DSPXR4ti]

So had an event this weekend and with the new rotors on the rear, what a diffenence! I believe the reason my rear brakes worked inconsistently was because they didn't get any heat, they really work now very happy.

If you remember about the right rear shock not working right, well this weekend really told me how if you just over look the little things it will be hard to set your car up right. I wasn't looking for the shock problem but when Mike said "your car is really lose" you check things, anyways What a diffenence today when the shock is working like it should.

Things to check:

Check the Gas tank if it's lose and not leaking in anyway.

Install rebuilt L/R shock, just to make sure both shocks working the same.

Get the XR weigh again & corner weight, Double checking min. weight again and if nothing else know how much it weighs when I get the gas right down to a Gal or less.

Check front toe, may have gone to far out.

Car/XR is really fast right now, one little problem I'm have is a shimmy at high boost, Ray, Chris, Paul do you guys have/did any of these problems and what did you find.

Ben

[Ray]

Define "shimmy" Ben?

[DSPXR4ti]

Define "shimmy" Ben?

It feels like the drive shaft is just off balance, it feels like the center carrier bearing has like a wobble then a shimmy and only under full boost, I replace the 2 piece drive shaft with a 1 piece and it helped, next maybe the clutch and the trans mount. Ray do you have a ploy trans mount, it could be something else and I may tie down the trans with more of a soild type mount to double check but this weekend is a big 90 sec course and may have to shift into 3rd gear and the clutch could be going AND! that could be it. I was just asking if anyone else has had this kind of "shimmy/vibration/wobble" to see if there's something else I could be checking.

Ben

[catapultkid]

I haven't experienced anything like you are mentioning. Are you sure its not just a little detonation? How are your motor mounts looking?

[DSPXR4ti]

I haven't experienced anything like you are mentioning. Are you sure its not just a little detonation? How are your motor mounts looking?

Things to check for sure, I was just talking to a friend here John Keefe about the same thing, I may change the right side just to be on the safe side but the left side is good, that I know.

I love the fact that the list is getting smaller every day and finding stuff like the right rear shock, possible clutch weeks before the National's is great, still have 3 events before the National's to work on driving and little details on the car, 3 weeks is to long time right now, me and the XR are having long talks together.

I'll Let you all know of the total weight at the end of the week, with a list of the major parts that weigh the most, If your interested.

Ben