Rob T's 818R Build Thread

[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....