Racecar Rebuild: its been awhile!

[6G72gearhead]

I have a GoPro Hero 3 and a Nikon pocket camera, the GoPro video is getting edited with the footage from the D7000 and the pocket cam, but I should have that up later in the week.

There where some other really badass cars out, I have video of quite a few of them so that will be in my compilation. I really hope I got my full spin in one of my first runs during the slalom, I think I brushed it off pretty well.


xd_01, its an autocross, you should do one. They aren't as fast as track days, but with how tight all the features of the course are it will train your instinctual reactions to be very quick with correcting oversteer and understeer. I'm hoping to get out to a few track days this summer, but autocross is way cheaper and more accessible practice in the meantime.

The BFG Rivals run slaloms soooooo well, I never dreamed of a street tire that would handle how these do. I guess it doesn't hurt that they are 255 width.

I placed 2nd in SMF (Steet Modified Front Wheel Drive), I lost to a Mini Cooper S, of the turbo variety, who had an upgraded turbo pushing it to 260 whp, so 70 more then what I dyno'd at, and was on Hoosier A6 r-comps. He only beat me by .7 seconds, and Saturday I had him by 1.5 seconds, so the car has a lot of potential, I just need to learn to guide it to that.

I'm seriously researching a new tire set up, I need R-comps, and I need bigger, so I'm measuring for a 295-315 front tire and a 275 rear, if the rear doesn't work 255's out back fit and will suffice, but I need big steer wheels, and the softer compound will be a bonus as well.

[6G72gearhead]

Here we go, here is the video from the actual even Sunday.

https://www.youtube.com/watch?v=7aHCW8-Komw

[coconut]

Looks like fun!! Awesome job in the handling skills.

[8thLS6]

Nice driving, plus I like how you can see the changes in approach for different turns in between runs. Even if you didn't post times, you can see the improvements

[6G72gearhead]

That is 100% why I film my runs, I'm really disappointed the driver cam didn't work. I can review the footage at a later point and figure out what is costing me speed on course.

Again, its unreal how far this car has come, when I started I was one of the slowest out there, now I'm consistently in the top 20 cars, including the formula cars, shifter karts, and the full prepared monsters. This past weekend in RAW time I was 12th overall, outrunning the SM Evo that is considered a national competitor.

[wetamup2k3g]

Very nice driving there!

[6G72gearhead]

Thanks for the good words guys! This last event didn't go quite so well though, all my competitors got to run 1st heat, which ment they ran dry runs, and the only dry run I got was my first, and I coned at the damned Chicago box, which would have been good enough for 1st if I hadn't coned. Oh well.

The car will not longer start in the rain. If its not raining, I can hit the key and it fires right up, rain starts to fall and it won't turn over and acts like a bad battery... Weird.

So what do you guys like for seats? Keep in mind I need bolstering and light weight, also being able to use a 3 point while driving to and from the track is also important. I have a hook up on NRG stuff through a guy in town, I have also been looking at Ultra-Sheild seats as they are a popular choice among the really fast guys.

[DEADEYES]

I personally think that stock cloth 350z seats are very nice, they are also pretty darn light iirc. Dunno what they usually run but just a thought.

[6G72gearhead]

Those are comfortable, but I'm looking for like sub 10 lbs.

I really wish I fit in a 350z, they are fun cars!

[greddy]

Recaro SPG, Bride Vios 3. I like both. Both are in the realm of 12-13 pounds though. I daily my car with a 3 point on the bride works great since I have it fed through the side slots. What are your pertinent dimensions?

[DEADEYES]

Those are comfortable, but I'm looking for like sub 10 lbs.

I really wish I fit in a 350z, they are fun cars!

Ah I forgot for a second that your car is a track/autox machine lol

My friend has one and aside from the shitty plastic interior pieces (like all cars now days) its a nice car to drive and abuse in the winding country roads.

[6G72gearhead]

Currently the issue with Sparco, Recaro, Bride and all them is cost, hopefully that will change at the end of the year, but for now its a battle.

This is what I've been looking at as they seem to be pretty popular with the cone race crowd, I think I can make the 3 pt work with them as well.
http://www.ultrashieldrace.com/catal...Sport-Seat/160

[6G72gearhead]

So the car tried to eat the wiring to the crank sensor at the track today. Fortunately it just grounded out slightly and I was able to fix it with zip ties and electrical tape, but now I gotta fix it right. I'll have video up here in a day or two since I took a pretty sweet spin. I just felt off my game though, with such a busy weekend and rushing to get to the event took a lot out of me, hopefully next event will go more smoothly.

Martin I'm a 16" seat width. I can fit in a 15" but its rather tight.

[6G72gearhead]

Took the dyno performance testing class this past week, and since I had the only tuning system for a personal vehicle we decided to tune the Galant on the schools dyno so other students could see what was involved with adjusting a computer controlled fuel and ignition system.

Here is how the day went, started with a baseline runs, since the instructors at the school are used to using the dyno for diagnostics and IM240 emissions tests and don't really do anything in the performance industry they insist on using the DLC to obtain the RPM signal for OBDII vehicles and are dependent on a smart tac, which doesn't work. So I finally figured out how to set the rpm through wheel speed.

This is what a dyno graph looks like with a malfunctioning DLC. Here is 2 of the baseline runs, not sure why both got printed.



The next one is more interesting, you can see how the curve should look, but with the DLC trying to fall off and losing RPM signal its interesting to see that peak hp and tq where fairly accurate, but the graph itself is useless.



After learning about how different dyno's work, and their accuracy potential I have no interest in using anything other then an eddy current or a water brake type dyno, the others are just not accurate, (except for the big AC/DC units, but its pretty much only the OEM's that can afford them) so any measurements for scientific purposes should be taken with the most accurate instruments available. An eddy current dyno has the ability to hold an engine at a constant rpm no matter how much throttle you throw at it.

So to tune ignition timing through more then just WOT conditions we set the dyno to hold a certain rpm and logged as throttle was applied all the way to wide open. This allowed me to set timing from 30% to 110% load. We did this test every 500 rpm from 2500 to 6000. If knock was found the timing was retarded 1 degree and the test repeated. If no knock was found ignition was advanced 2 degrees until the knock threshold was reached, once found timing was retarded 1 degree and test repeated.

I wish I could have done fuel, but without a wideband was not something we could have done accurately.

So this is the baseline after the first round of tuning, this time using rpm calculated through wheel speed.

Boom, here is what a dyno graph should look like. Here it made 204 hp and 214 tq, the final run in this series made 206 hp and 224 tq.



We continued to tweak the timing side of the tune and eventually pulled another 10 hp out of it. so during the day we went from 198 hp to 216 hp, I wish the 216 hp 226 tq graph got printed, but here is 214hp and 225tq, which is close enough.

The spike at the beginning of the graph was me waiting too long to shift into 3rd, since the test window was set to start at a certain wheel speed it started recording just before the shift.




What I continually notice is the manifold pressure stays high all the way to around 4500 rpm and then starts to gradually drop all the way to the rev limiter. It doesn't drop an incredible amount, to a maximum of 3-4" hg, but I really wonder if there is power gain to be had with a larger throttle and a good freer flowing manifold.

The other issue is at the lower end of the graph tq is flatlined until 3500 rpm then ramps up very aggressively. Is this a normal thing that might have something to do with the cams or could this be due to my fuel map not being tuned correctly? Since that is around the rpm I exit most corners at I'd like to try and improve power in that area, of course to get into fuel I need widebands.

[6G72gearhead]

So I found 6G75 Mivec for $650.........

[Silvertune]

You'd blow that thing up in no time putting it through the events you take on.

[6G72gearhead]

Really? I need something that can hold 7 grand for an afternoon. Would ARP rod and main stud/bolts help at all?

[Silvertune]

You'd have to get the block completely blueprinted and balanced with the ARP bolts and studs, but then you should have no problem revving it as long as you don't cross the 7000 rpm line. The 3.8's use cheap bearings and the short rod long stroke nature of the shortblock doesn't mix well with them. People spin main bearings with them, rod bearings, stretch main studs, you name it. All that with wayyyy less abuse than you're rambunctious 3.0 endures.

[6G72gearhead]

I see, that is disappointing. I knew it wasn't a good design for high rpm use but the extra power is tempting. This is why I'd like to find out how to make good N/A power from the lowly 6G72. It would be nice to get good power out of an engine that will live at 7500 rpm all day long.

[Silvertune]

272's, big tb, big IM and some very precise port work and you could see 260whp all day long.

Course if you're a real sucker for punishment build a 3.7 long rod mivec motor with RPW stage 2's. 400whp all motor on pump and 7500 RPM's no problem.