Rob T's 818R Build Thread

[Rob T]

4/10/25 - Had a successful track day at Carolina Motorsports Park. Weather conditions were perfect. 15 cars in my run group. It's been a while since I have been to the track, so was working out some of the kinks. Car ran well. More to follow. It was the very beginning of a "Gridlife" weekend. Lots of interesting cars and people not normally at this track were in town.

[Rob T]

5/23/25 - The track day that almost was....Had the car loaded ready to go, heading down road at 4:45am (still very dark). At the first stop sign, 1/4 mile from my house, all the lights on the trailer went dead. No way I was going to drive with a blacked out trailer. Today will be troubleshooting mode to find the short(s). Bummer. The weather was going to be perfect, and it was test/tune day, so 30 minute sessions sorted by engine size.....Keep reminding myself that everything happens for a reason.

[Rob T]

Update: Dug into the trailer wiring. Found almost the entire back section (2 left marker lights, 3 center marker lights, 2 right marker lights) wire melted, along with the two prong plugs on the lights. Looks like one of the plugs came out and dead shorted. Not sure why the wire burned/melted, but most of the insulation is gone from the copper. Parts ordered to rewire the entire back of the trailer....

[Sgt.Gator]

Well that's a bummer. If it had been mine there would have been 50 gallons of race gas next to it!

[J R Jones]

Two years ago I bought a used Honda Ridgeline. Some time later I rebuilt a trailer dolly to pull behind our RV. I attempted to test the new dolly lighting with the Ridgeline. Not all the features worked and after rechecking my installation I found a lack of power on the Ridgeline seven pin socket. With a Google search the Honda schematic revealed an accessory fuse block in the engine compartment, devoted to the trailer plug so that a trailer wiring failure would not take out the truck fuses. My accessory fuses were (previously) blown. In your case I do not know how that level of shorting did not take out your fuses, or did it?
jim

[Rob T]

This was very curious, but a case of ignoring some warning signs...A few month ago the running lights didn't work. Found a blown 7.5A fuse. Replaced it as a "one off". Trailer lights worked fine for several trips. This time when I hooked up the trailer, no lights at all. Went to the Aux fuse box, the 20A fuse next to the 7.5 was "exploded" - like it burned up. Also partially melted the fuse box plug in point itself. Also the 7.5 blew. the 7.5 is for the running lights. The 20A is for brake and turn lights - all just the trailer. My working theory is that a plug came out of the marker light on the right side of the trailer (running light) and caused a partial short. Not enough all the time to blow the 7.5 fuse, but enough to heat things up. Ultimately, the wire melted/burned away, but also impacted the turn signal light (a three prong plug) and caused that to dead short. The insulation was gone from the running light feed wire all the way across the back of the trailer. So....solution is new plugs, new wire across the back of the trailer....that work is in progress.

[J R Jones]

Rob, In my experience 20amp fuses are for motor, solenoid and brake devices. That is high amp for lighting. The intension is to sacrifice the fuse and save the wire harness.
Are your electric brakes OK or is that circuit powering your lights?
jim

[Rob T]

Brakes were OK. There is another fuse for the brakes.

[Rob T]

Track day today at CMP. Went well. I did three sessions. Start temp was 75, but it was 90 by the third session. Oil temp was 210. My AWIC feed water was 102 and I was seeing 118-124 temps after the intercooler. Highest coolant temp was 205. It looks like I got all my slow coolant leaks taken care of. I shadowed a Miata the first session to see how he drove some of the corners I was struggling with. They have to carry momentum to be fast. The next session, I kept that line, but didn't follow the Miata and dropped almost 6 seconds off my time shadowing the Miata. Got within a couple of seconds of my fastest time ever. Last track day was April, so I was a bit rusty. Also, 90 degrees in sun, a helmet and full race suit (no cooling) is HOT.

[Hobby Racer]

... Also, 90 degrees in sun, a helmet and full race suit (no cooling) is HOT.

I was suprised at the amount of cooling I got @ VIR in the 90+ weather. So long as I was moving I did not got hot. As soon as I came into the pit though, meltdown...

[Rob T]

Yeah...too much to concentrate on while on the track to feel hot. It really hit when you stopped driving.

[Rob T]

Some stats from my time at CMP:
Best lap: 1:53.232 - I had a few of the best laps I've had in a while.
Braking G max: 1.13
Accel G max: 0.61 (power a little off in the heat)
Left turn G max: 1.32
Right turn G max: 1.35
Max speed: 112.5

Won't be able to get back out until September. But I'll be ready and excited to go.

[Rob T]

Here is a link to two good laps from 6-28-25 session at CMP. I spent the first session and the first several laps of this session shadowing a Miata running around 1:58 or so, but learning the line he was using. I passed him just before this video begins:

https://youtu.be/xKy7vFE9LHI

[Rob T]

9-12-25: Made it back to CMP today. Weather was perfect. Car ran great. I forgot the SIM card for my Traqmate data logger, so no video or lap timing. I used that to really focus on the driving. I feel like I made some progress on a few of the turns that have been plaguing me. Overall a great day. I did my typical 3 sessions. There is another opportunity in two weeks, weather permitting.

[Rob T]

Had a great track day today at Carolina Motorsports Park. Weather was perfect. In the third session (of the three I drove), I bested my best lap time every by a few hundredths of a second. Car was running great. I am experimenting with tire pressures. Next time out I will try a bit lower. Today I was 35 front, 38 rear hot temps. All of my fastest times are with this pressure. I have driven 82 twenty minute session since 6/5/20.

[Rob T]

Another track day yesterday at CMP. Again weather was perfect. 12 in my run group. There was a Challenger/Charger with the 800+ supercharged motor set up for track duty. Some interesting comparisons....His car 4,400 lbs, mine 2200 with me in it. His car 800+ horsepower, mine 285. His car 10 gallons of gas per session, my car 3.

Car ran well. Lots of power in the cool air. Worked on tire pressure to see if I could find the optimal grip. Car feels balanced. More facts and figures after I get to analyze the data.

[Hobby Racer]

... There was a Challenger/Charger with the 800+ supercharged motor set up for track duty...

I gotta ask, how quick was he?

[Rob T]

Ran away from me on the straights, but was a bit slower than me in the corners, but once past me, I could never catch him. He had done a lot of work to get this car ready for the track. No seats, completely redone suspension, lots of engine mods. It was a monster. It's just fun to see the different ways to approach speed. The penalty for big mass is high when measured in consumables (fuel, brakes, tires, etc.)

[Rob T]

I ran my best lap time ever at CMP. It was a 1:51.601. This is the quickest lap by 0.2 seconds. I started that session with hot tire pressures of 38 rear and 35 front and ended the session with 40 rear and 36 front. Here were the fastest three lap times: 1:52.766 (lap 6), 1:51.601 (lap 7), 1:51.969 (lap 8). For the third session I let some air out after the second session. This gave me a hot start pressure of 39 rear and 35 front with a finish pressure of 39 rear and 35.5 front. My three fastest lap times were: 1:54.980 (lap 3), 1:53.578 (lap 6), 1:53.748 (lap 7).

The second session had higher tire pressures by about 1 psi and all my fastest times have been at that pressure. Seems counter intuitive, and I'd like to hear some thoughts from the forum. I am running Federal FZ-201M 100 treadwear tires.

Max speed for the day was 117.1 with a calculated max HP of 249 and a max torque of 295. Left and right turn "g" of 1.25 and 0.99g of braking. I am seeing about 12 degrees of temp increase from the AWIC feed water to the IAT. Highest IAT was 110F with ambient temps around 75F.

[Bicyclops]

What size are your tires, Rob?

Ed

[Rob T]

Rear: Federal FZ-201M - 255/40ZR17
Front: Federal FZ-201M - 235/40ZR17

[Bob_n_Cincy]

Rob, is your IAT located after the AWIC cooler?
Are you running a Speed Density tune?

My MAF/IAT (Mass Air Flow/Intake Air Temperature) is still located in the stock location, after the air filter.

My tires are the same size as yours, except for the Toyo R888r
Bob

[Rob T]

Bob: I am running speed density. That was changed from mass air flow after one of the heads crashed while I was still in CA and had the motor rebuilt. I had that tune re-evaluated when I lived in Roswell and tracked the car at about 7,000ft elevation. That tuner told me it was a very good tune and he could find nothing to change. IAT is after the intercooler. I also measure the temperature of the water supply to the intercooler from the front mounted radiator. Typically, there is a 15 - 20F rise in temperature comparing water supply to the intercooler to the temperature of the air after the intercooler. When I am on the track, I use the COBB to monitor two of the knock values. The only day I ever saw a fine knock correction was then the ambient air temperature was approaching 100F and was above that on the track.

[Rob T]

Spent the last couple days getting ready for the season: New oil/filter, new trans fluid, new brake fluid, new front rotors and a full inspection of everything else including cutting open the oil filter (totally clean). Bedded the new rotors on the street in front of my house. Being on the road and not a track reminded me how fast these cars really are....The season could start as soon as February 27.

[Hobby Racer]

Wow, I've still got over 2 feet of snow on the ground in the northeast!

[Rob T]

Hobby: You'd make an excellent neighbor....come on down!

[Rob T]

Got back to CMP on Friday 3/20 for three sessions. Weather was perfect. Car ran great. It was a race weekend so there were a lot of cars there. I'm running into an interesting "physics" dynamic at the track. Corvettes, Mustangs, Camaros, and Challengers/Chargers are generally able to pull away from me on the straights. The "problem" for me is that I brake at the end of the long straights at about the 300 ft marker. They are braking at 400 or 450 - so I end up scrubbing max speed to avoid rear-ending them and it "costs" me time as I could do the turn much faster than they can - the difference between 2200lbs and 3800 - 4200 lbs. We operate with point by so they don't see me on the straights and are not looking behind them in the braking zones or on the turns. Given an open track, I think I would be faster, all in, but usually end up pulling into the pit for space for space, which works fine. At least I have comfort in the knowledge that they are using way more gas, tires and brakes than I am ;-)

[Hobby Racer]

I know the feeling! Luckily the group I run with adopted a new system last year allowing passing without point by's. At first we were all a bit nervous about the new system, but it turns out that it has raised everyone's situational awareness and it works really well. You are now very vigilant about what/who is around you because they might be passing at any time. Makes for great sessions and much less congestion.

[J R Jones]

Unlike track days, racing will require stealing a corner to gain a position. I exercised that starting from the back at Mid-America raceway in MO. The front straight ends at a hard right hander with the flag staion on the apex tower. The line was from the straight left edge to the tower and out. I got the door slammed on me by slower cars several laps. Consequently I ran down the right side into the corner braking late and ruining the corner speed for both cars, but I gained positions. Despite the compromised corner, I had FTD on most laps. In your case the more powerful cars may just re-pass but they may think better of it.
jim

[Rob T]

Hi: I had a track day yesterday. It got off to a rough start. Somehow, I left the main power disconnect on and my battery was dead flat. I had to jump the car for each session. I put a charger on the battery when I got home and it indicated that it completed the charge in 5 minutes.....It's 5 years old, so the loss is not as heart wrenching. Still a stupid mistake. Here is the day ending issue: After the second session, as I was coming off the track, the car was idling between 1,000 and 3,000 rpm in rapid succession with a corresponding rapid cycle on the AFR gauge from "green" to "red" when the clutch was depressed. I was able to drive it to the trailer and on the trailer, but something is not right. I didn't notice anything during the session. I have not done any investigation yet, but was interested in the forum's ideas of where to look first. EJ257 Turbo. What I have so far as recommendations is to look at all of the vacuum lines around the turbo system - theory being there is a leak or a hose blown off a fitting that is messing with boost control. I am hoping for "easy" but if that is not it, where else should I look. The car was not missing. Thanks in advance. Rob

[Rob T]

One other thing. This car is speed density.

[Bicyclops]

Only with clutch depressed? How about in neutral?

[longislandwrx]

are you still running the idle air control valve? clean it and change the gasket see if it fixes your idle issue

[Rob T]

Update: I have drive by wire. No apparent idle air control valve. Engine idles at 2100rpm with clutch out, in neutral. When I stab the throttle, idle returns to 3100 for a moment then drops back to 2100. There are a few random "stumbles" but otherwise idle is consistent. The car is not missing. Suspect an intake leak somewhere, but I am going to do a COBB Accessport log to see if I can learn something about the throttle position.

[driveslikejehu]

just throwing stuff out there...
don't know what throttle you have; when my DBW throttle began to go it gave erratic responses. Its just a wiper type rheostat that gets mechanically damaged after a while

[Rob T]

Problem Found. Now awaiting repair. Thanks to Hobby for some hints.....I did a Cobb Data grab of a lot of throttle and Manifold parameters. Also compared to an old log when the car was running well. Big difference was idle RPM and Manifold Absolute Pressure as well as the airflow at idle. Was in the process of unplugging the drive by wire throttle from the throttle body when my hand felt a "breeze" around the intake manifold. Started reaching around where I couldn't see and my finger got sucked against an uncovered nipple at the base of the throttle plate. Scared the crap out of me. Put my hand back down there with the intent of putting my finger over the nipple and when I did, a beautiful, slow, steady idle happened. When Chad built the car, many of the "unnecessary" nipples and ports were plugged with thick rubber caps. After 10 years some of them are cracking. The missing one actually cracked and broke off, I'm guessing from the shift from vacuum to boost that happens many times per lap. This explains the sudden appearance of this problem. I have ordered a kit of new plugs/caps and will replace all of them. The challenge for the failed one is removing the hose from the discharge of the turbo to the intercooler, which is blocking my sight and ability to reach this fitting to make the repair. It's great to have found the issue with certainty. Thanks again to Hobby....