620 Land Speed Record

[Stoffregen Motorsports]

Focus on making it driveable. Tune it for at all levels of throttle input, not just WOT.

[distributorguy]

Correct.  That came easy with the base jets.  It was the top end that fell off the spectrum.  It idles and runs at 12.25:1 from 600-4200 rpm then goes lean.  By altering the idle jet settings and raising idle to 1200, I can lean out the mixture to 13:1 until it hits the top end, then it goes MORE lean.  That's why I now have 130 air correctors in the carbs, to see what happens under load.  I think its pretty close.  We'll know soon enough.  Thankfully I have a set of wheels/tires for the rear that should hook up a little better on the dyno than narrow Goodyear Frontrunners.  Otherwise the whole concept of dyno tuning it would become a complete waste of time.  

[Stoffregen Motorsports]

Bring a couple different emulsion tubes also.

[distributorguy]

I don't have spare sets of 4 of any emulsion tubes, unfortunately.  What I've found is that when I'm this close on emulsion tubes, the next step up or down is HUGE, so it comes down to changing hole sizes in them with solder (or just flux) and jet drills.  Plus, emulsion tubes do come into play at higher rpm, but the real reason to change them id for a smooth off-idle-transition into the main jets.  We're never running under 3000 rpm.  Ever.   Except while letting out the clutch.  

[distributorguy]

So, no dyno pulls last night.  

 

Got the truck there, warmed it up, waited to get it on the rollers, and when attempting to restart something went horribly wrong.  Figured out our Aeromotive fuel pressure regulator puked its O-ring and held the regulator open to fill all 4 cylinders with 16 psi of fuel.  Not good.  Washed the cylinders and rings clean.  We managed tot get it cleaned out, inspected the bores, added oil, did a compression test, and replaced the O-ring in the regulator, along with a new set of race plugs.  Everything looked good.  Started and ran well.  Then on restart it puked the O-ring again.  Beer time.  Better here than at Bonneville I guess.  At least that's what everyone kept saying, and as much as I know its true, only 19 days until we leave.  Time to call Aeromotive and see what they have to say.

[Stoffregen Motorsports]

That sucks.

 

Which o-ring blew out? Internal problem or fuel spraying out?

[distributorguy]

There's an O-ring at the pressure regulating bearing inside.  Pushed a couple quarts past the needle and seats.  Aeromotive is red labeling replacement parts to me tomorrow (Sat).  I posted a pic of the failure on Instagram.  The folded O-ring held the regulator wide open.  

[Stoffregen Motorsports]

I'm sure your motor will be fine.

 

I used to worry a lot about engine assembly, like to the point of being surgical, and Dave (Rebello) told me to think about the kind of abuse an engine sees on the track. That put things into perspective for me. Motors can take a lot if the parts are chosen accordingly.

[datzenmike]

Maybe replace the oil if the gas got into it past the rings, squirt of oil in the cylinders and it will be fine.

[Stoffregen Motorsports]

I think fuel wash is only a big problem when it occurs over a long period of time.

[datzenmike]

Agreed, like a choke on all the time.

[distributorguy]

Yep, its not like abrasives got into the cylinders, and no heat was generated in the process.  Now I'm adding a 2 5/8" fuel pressure gauge where the driver can see it in the opening of the hood scoop.  I'd like to try the regulator with no O-ring installed to see if it still meters the same.  Thanks to Aeromotive, I now have a spare valve assembly if (when) the O-ring swells again.  The fuel at Bonneville will be worse and it'll likely happen faster.  At least now I know to pump the system dry and run the truck out of gas ASAP after a little more testing.  

[distributorguy]

Yesterday I got the fuel system updated with a huge lighted fuel pressure gauge installed inside the hood scoop, and a smaller gauge on the regulator.  Now the driver can see the fuel pressure while driving, and fuel isn't within 2' of the driver, outside the cockpit.  I also upgraded the oil pressure copper line to a braided stainless line.  

 

We spent the rest of the evening going through bailout drills so the driver (TC Worley) can get comfortable for the tech inspection process of displaying that he knows where all controls in the truck are, even blindfolded.  And that he can also remove his belt system (5 point plus arm restraints), disconnect from the CoolShirt cooler, Pull the pin for the swing-away helmet restraint, remove the pull-off steering wheel, drop the full door net, open the door, and successfully get out of the truck in under 30 seconds.  His average was 16 seconds by the end of the evening.  

 

Today I'll be working under the truck - oil change, tie up loose wiring, make a cover for the fuel pump and filter to protect it from debris, and most importantly continue work on the 1/4" plate steel flywheel scattershield.  By 7pm, TC will be back with a gaffer to take some "glamour shots" of the truck.  He's also working on a video of the build and race.  You can see some of his work here, if you're interested in that kind of thing (he does some REALLY cool photography and video work!!!)  https://vimeo.com/tcworley

[distributorguy]

The photo shoot ran until 1am...  very cool stuff.  The gear they used was worth far more than the truck!  

 

The truck's back up and running - very well in fact!  Fuel pressure is better than ever - and we can now push it up to 6 psi if needed for volume.  

The scatter shield is done, except for a cover over the slave and clutch arm.  Still trudging away at that.   :yawn:

Had to partially drop the transmission to test fit the scattershield.  Now the torsion bars are in the way.  I see coil over shocks in our very near future.  That will also allow the use of a belly pan, so multiple benefits.  

Unfortunately, the shield has to be put into place delicately, while getting bolts are tightened in a perfect sequence or it'll never go back together.  I should have just run a T5 and a Chevy adapter plate.  This is a royal pain.  

[Stoffregen Motorsports]

Man, I wish I were building race cars again. I have soooo many tricks up my sleeve now that I've been doing it for so long. Stuff I didn't know about when I was young and racing.

 

QA1 is right there in your area, right? Maybe they'd give you a small sponsorship.

[distributorguy]

Viking is better than QA1, by far.  Its comprised of all the pissed off engineers who care about product quality and left disgruntled.  Yes, they'd likely give me a small discount.  QA1 won't even let you buy local.  They referred me to Summit.   :confused:

http://vi-king.com/

 

Feel free to call or email or DM me with tricks...   :thumbup:   I'm thinking about dropping the truck OD gears into the 280Z trans for now, just to see how it plays out.  I don't know that there's time???

[Duke]

Man, I wish I were building race cars again. I have soooo many tricks up my sleeve now that I've been doing it for so long. Stuff I didn't know about when I was young and racing.

 

Feel free to share them!  Passing along knowledge only helps the community in my opinion.  As stupid as much of the internet is, I think one of the best things about it is that it enables people to easily share the type of knowledge that you are talking about.

 

Plus, because you're not racing anymore, you don't have to worry about the competition using your tricks to beat you :thumbup: . 

[Stoffregen Motorsports]

The tricks I'm referring to more or less relate to how I look at building a vehicle. I am not afraid anymore to cut into a body or frame or whatever. My skill set is much more vast now and I am able to make changes to most systems in the name of performance or ease of maintenance.

 

Thinking about the past race cars I've built, or worked on, or pit crewed for, I remember a lot of those situations Like Jeff is referring to with the scatter shield and I'm thinking about how I would make those problem areas easier to get to.

 

Nothing scares me anymore. I'm not saying you (Jeff) aren't doing it right, I'm just saying that I love those challenges. Finding the solution is very gratifying for me.

 

No offense to anyone here when I say this (I live in CA where migrant labor is standard operating procedure), but sometimes I feel like a Mexican. When a job comes in and I have no idea of how I'm going to tackle a job, I still say "Yes, I can do it!" Then I come up with a solution as I count sheep at bedtime.

 

Sorry for the threadjack...

[distributorguy]

Not a threadjack - 100% pertinent!!!

 

The plan was to "get by" with a Datsun trans this year, then move on to a better gearbox and cut up the floor for access at that time.  I wish I'd already cut up the floor.  Last night I had to remove the motor mounts and lower the motor in place in order to get the trans mated with the engine with the scattershield in place.  Its that tight.  SO many things had to be removed to make that happen.  If the custom ballistic blanket had fit properly, it wouldn't have been an issue and the truck would be 100% ready for the trip.  Instead, I ran out of welding wire last night, and the truck is still on the hoist until the clutch arm cover is complete since I needed to make sure it cleared the torsion bar before final welding.  

 

I totally understand working all night.  Some times I wake up with the best solutions after 6-7 hours of "rest."  Last night I figured out my schedule of how I'll get the Datsun finished tonight, along with fixing the generator we'll bring along, and timing to get my truck ready for the long haul.  I still need to get a box liner sprayed, its being undercoated today, and this weekend the new plow mount gets installed to hold the push bar, should we need it.  Did I mention my Ford truck crapped out permanently a week ago?  We'll be on the road in 9 days, towing with a new Chevy.  

[datzenmike]

 

Feel free to call or email or DM me with tricks...   :thumbup:   I'm thinking about dropping the truck OD gears into the 280Z trans for now, just to see how it plays out.  I don't know that there's time???

 

The OD gears are pretty much the same at 26/44 or 0.594. What Nissan did was change the main shaft to counter shaft input gear ratios  A 22/31 (1.409). gives you (1.409 X .594) = 0.833 OD

 

Putting a zx input set of 23/29 (1.261) changes every gear including the OD to (1.261 X .594) = 0.745

 

Two different OD ratios using the same OD 'gears'

[distributorguy]

We have an overdrive here that was originally in the truck, with a wide ratio gear set and roughly a .93 overdrive (guestimate on shaft rotation).  That's the set I was referring to.  

[Stoffregen Motorsports]

If you have a couple different transmissions laying around, you will probably have enough gears to mix and match to get what you want. But if you're going to swap to a different trans, why bother. Sounds like you still have plenty to do.

 

The big green Ford crapped out? What happened?

[Stoffregen Motorsports]

I guess I am a little jealous. I wish I had the time to build a race car.

 

Again, thinking about how I used to build them vs how I would do it now, I used to build the drivetrain and suspension (in my own racecar) to be very durable. Now, I realize that a loose diff, trans, suspension, wheel bearings, etc would be much faster, though would definitely not last as long. But who cares when you're trying to win races?

[distributorguy]

Don't be jealous - be active.  Come join us at Bonneville and be a part of it!  This is our first year, not our last!!!

 

Big Green is fine.  It was my 2008 F250 V10 gas motor that dropped #5.  The new Silverado 3500 is already undercoated, going to Line-X in 30 minutes or so. What a pain in the arse.  

 

I wish I had the gears I want for the trans, but I'm missing a couple ratios that would be FAR more ideal than the 280Z offerings.  I have 3 boxes, and I'm close, but not really.  The BMW box in the back corner is SO much better, but it'll be a terrible fit in the truck - especially knowing what it takes to install the scattershield.  Impossible without losing the torsion bars.  Then there's the problem of the custom driveshaft that no local shop will touch, which is a bit surprising.  

 

Even if I sort all this out and fit a different trans, it could be argued that we're breaking the rules by eliminating the torsion bars - not because its not allowed.  Rather, because it affects the aerodynamics of a "production class" truck by changing airflow under the vehicle.  Then I think, why don't we fit a world-class trans, and get set up for the next engine that'll move us up to the 200 mph mark???   We all know that's the next goal.  I think 1100 hp will get us there, or at least 1000 ft lbs of torque.  Maybe it will need the new Cummins V8?   :poke:

[datzenmike]

I have an '85 200sx turbo 5 speed. I believe it's a wide ratio with a 3.594 first. Some day I'll get it out and count the input main/counter set. Very curious what they are. I know if you put the zx input set into a regular 3.321 box it drops them all way below the zx ratios with a 2.972 first. It retains the 0.745 OD though