Jump to content

620 Land Speed Record


Recommended Posts

The engine updates are coming along nicely.  All of the EFI hardware is here from Jenvey as well as the dry sump system which I hope to have almost done tonight.  I'll post pics tomorrow, time allowing.  

The goal is to build a different exhaust system and make the truck "street legal" after hitting the engine dyno to develop a base program for the EFI and distributorless ignition setup.  Street tuning and an effective barometric pressure sensor should help eliminate a lot of the hard-core tuning issues we fought in the past, after our first few runs anyway.  Another race team may be donating telemetry to us so we can do a better job tuning as well.  Fingers crossed for this year.  

  • Like 2
Link to comment
  • Replies 870
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Yes I fell off the map for a while.  Its been a very busy Winter.  Loads of snow, and an equal amount of work.  


I'm using the roughly 1" thick throttle bodies on the manifolds we ran previously.  Unfortunately, not a lot of work was completed last night.  I'm in the midst of renovating part of the shop, so there's stuff in the way everywhere.  Its time to test fit the motor, just to verify the oil pump will fit in its current location, and to be certain that when I weld the evacuation fittings to the oil pan that they will clear the steering box.  


You can see the hardware here:

Throttle bodies

  • Like 1
Link to comment

Are the injector bosses in the throttle body, or do you have to weld them into the manifold?


We've had a helluva winter too. Here, that means record rain and little sunlight. Massive wind storms, hail and the occasional snow. I remember MN winters from when I was a kid. I sure do miss snowmobiling...

  • Like 1
Link to comment

The injector bosses barely fit in the 30 mm thick throttle bodies, spraying directly at the head's intake port behind the throttle plates.  Given the ideal taper to the intake manifold, there's really no advantage to welding the ports into the manifold closer to the head. 


Work stalled, as the next step is to test fit the motor in the chassis again.  Until I get the shop better organized, there's no way to get the engine hoist to the truck.  Hopefully by the time this weekend's snow storm lets up, I'll have a chance to get that done and make the next series of steps forward.  We've had some record snowfalls and record low temps this season.  I can't wait to be sweating my butt off on the salt in August again.  

  • Like 2
Link to comment
  • 3 months later...

We've been at it hard all winter/Spring.  We plan to be there, if the salt dries out.  Its still a lake right now.  


Last night we started programming the EFI computer.  Just about everything else is done being assembled except a new 3" exhaust system out the back.  Pushing it over to the hoist tonight to get that built ASAP.  Then back to electrical and getting ready to fire it up.  Finished the dry sump plumbing (except one vent line) 2 days ago.  Electric water pump and all associated plumbing/wiring installed yesterday.  You can see progress pics on  my Insta account at @jschlemmer.  Its too hard to post pics here.  

  • Like 2
Link to comment
On 11/18/2015 at 1:12 PM, distributorguy said:

Only a little cosmetic progress on the truck since July.  Since we're in "production class" no body modifications are allowed except a hood scoop up to 11" tall.  I'm still working with that.  

Photobucket hates my spam filter and is fighting me.  hopefully one of these works:


http://<a href="http://s1148.photobucket.com/user/distributorguy/media/datsunstripes_zpsyzjraydr.jpg.html" target="_blank"><img src="http://i1148.photobucket.com/albums/o568/distributorguy/datsunstripes_zpsyzjraydr.jpg" border="0" alt=" photo datsunstripes_zpsyzjraydr.jpg"/></a>


Wow ! Great build !

Link to comment

Has anyone here found a good way to install 3" exhaust on a severely lowered truck?  That's this week's battle.  Last night I ran out T304 stainless pipe from the new header to the rear axle.  Looks like I'll end up using an offset muffler to dive below the rear axle so we can exit the rear.  Worst case scenario, more work but I can plumb it out the driver's rear fender in front of the axle, but I'd rather not.  When its done I'd really like to be able to install a full belly pan. The entire front end could take a flat pan at this point, if it was legal in our class. 

 If the muffler shows up as planned, we may be firing up the motor Thursday evening.  

Link to comment

Why not out the side?


How about up into the bed and out the tailgate?


My 83 Toyota uses a muffler with inlet and outlet on the same end. this was so I could have a full length exhaust, but have it exit the side. I also used oval tubing to exit, just for fun as a nod to racing.







  • Like 2
Link to comment

My 520 is really low and I had to build a tunnel for the exhaust above the cross members in the floor pan, but I exited it just in front of the rear axle at the ground, I do have 5 inches to work with though.

A 3" pipe wouldn't leave a lot of room on my truck, but if I had someone do my exhaust over the axle I would have them squish the area above the axle into a flatter 1.5" oval shape, you likely don't care if it is 4.5" wide as long as the exhaust flows freely, I did that on my 521KC turbodiesel below the torsion bar mount cross member, but the exhaust is only 2.5" and that truck is not lowered either, it is also a straight section and squished flat on only one side, it is less than an inch away maybe from hitting that cross member, but it is mounted to that cross member also so it cannot move around a lot.




Edited by wayno
  • Like 2
Link to comment

I may ovalize tubing under the axle, or find a way to ovalize it going over the axle?  Exhaust gas can severely disrupt aerodynamics (this is for Bonneville of course) so I'd rather disrupt the vacuum area that forms behind the tailgate.  Pressurizing that area, even if its only a little, might make us a tick faster.  I only joke about the exhaust gasses pushing us down the course.  If we drop the tailgate (which is legal) it only make the low pressure area behind the cab larger.  


At this point, the exhaust is run out past the back of the cab.  I'll get a muffler in the mail today which will hopefully allow me to finish it up?  If not, we're still far enough along to fire it up tomorrow.   There's a great place to jump over the frame and come out in front of the driver's tire.  I wish I knew how to TIG weld though.  Stainless wire feed can at least be buffed out.  I found pre-heating the pipe before the first weld really helps since stainless is very slow to absorb heat.  

  • Like 2
Link to comment

Mufflers are not required.  I'm only installing one so we can street tune the truck, and to test its effect on power output.  Our old system was a simple header dumping behind the driver's tire with a 4" collector leading into a 3" dump.  Overall length from cylinder 1 to the exhaust tip was 36"?  Imagine the noise with 14:1 compression and .600" cam lift.   LOUD!!!  

  • Like 1
Link to comment

Borla doesn't make the offset I need, so for now I installed an open Thrush (cheap experiment.)  You can roll a racquet ball through it.  Tailpipe is tun straight out the back and nothing hangs as low as the stock fuel tank.  All 3".  


Hopefully we're far enough along to start the motor tonight. 

I just got all the air out of the cooling system since we're running a Craig Davies water pump.  Very nice pump BTW! 

#9 NGK race plugs installed.  Not sure if these are correct or #8s, but playing it safe.  I think we're closer to 13.5:1 now than 14.  

20W50 VR1 ready to pour in and prime the dry sump system. 

Cooling fan verified functional.  

Throttle return is 100%, throttle bodies balanced on the flow bench before install.  

Time to add 110 race fuel (its all we have) and check for leaks, adjust the regulator.  

Vacuum gauges installed. 

Timing light ready

Non-contact thermometer ready to check for hot spots (vacuum leaks.)  

Beer in the fridge just in case we succeed.  

Beer in the fridge just in case its an epic failure.  


Update:  no start, beer supply depleted.  Apparently 2 years of racing was enough to either kill the battery or the starter.  Battery tanked to 7V on start attempt, even with plugs removed.  I suspect to find significant corrosion inside the otherwise clean starter.  Other than that it has oil and fuel pressure.  


Confirmed: starter bearings completely failed, high amp draw. WIll be rebuilt by end of day Monday.

Edited by distributorguy
  • Like 2
Link to comment
  • 2 weeks later...

3 weeks until Speed Week 2019!

Its alive!!!

The engine runs well now, not full tuned but we're working on setting up a dyno session at a shop that specializes in tuning our EFI software.  MANY little issues resolved including a replacement starter since the rebuilt one stuck "on" from a faulty new solenoid installation.  New, bigger battery.  The list of final repairs and upgrades has shrunk significantly, although we'll need every spare minute between now and when we leave to get the truck finished.  Most of the work left is detail oriented, time consuming nut-and-bolt checkup stuff.  Safety wiring, cleaning up wiring, updating engine venting, etc...  I believe we are 100% in compliance with the rulebook and safety checklist. 

Best of all, the salt looks fantastic!!!

  • Like 2
Link to comment

We went simple with Microsquirt.  I like the fact that its almost waterproof, which means salt will stay out of it and reduce corrosion induced problems.  One of our team members has done a couple dozen installs, another has been tuning these since MS1 came out.  The latter is friends with a local dyno operator who also has been tuning that long, so I feel like the system is in good hands.  I've only installed a few systems, so my knowledge is not what you'd call in-depth.  

This system allows for individual injector firing as well as individual coil pack firing, although we're having issues with too many signals from the cam sensor so its running batch fire right now.  I installed a threaded cam sensor through the valve cover (drilled and tapped on the mill to guarantee its perpendicular to the cam) and cut back an oil pump eccentric to have 1 5mm wide tooth for the sensor to read.  Its picking up 4 evenly spaced signals per crank revolution or 8 signals per cam revolution, minus the fourth of the 4 signals.  In other words, 3 signals, then a gap, 3 signals, then a gap, per cam revolution.  Odd.  

  • Like 2
Link to comment

We had similar problems with a truck I built a few years ago. The solution was multi faceted, but switching from HALL sensors to magnetic sensors mostly did the trick. Or maybe I have it backwards, I can't remember.


Which are you using? Do you have a choice?

Edited by Stoffregen Motorsports
  • Like 1
Link to comment

Its a hall effect sensor, which by the way has a magnetic center.  Rumor has it they tend to pick up things adjacent to the sensor more precisely than straight ahead?  I'm waiting for an email from Matt at DIYAutotune for filter suggestions.  Ours is powered with 12V, but maybe a 5V input would reduce the sensor's strength and not pick up as many errant signals?  

In batch fire, the engine is now running pretty well.  We haven't gone above 2000 rpm yet, bet even there we're seeing almost 5 psi of vacuum pulled on the block from the dry sump, so I'm excited that everything is working as intended and we'll do pretty well after a day on the dyno.   I'm still amazed at the Davies/Craig electric water pump and how well it maintains engine temp at 170 - or wherever you set it.  

  • Like 2
Link to comment

Well, we experimented with 5V versus 12V on the crank sensor last night and it resulted in about the same issues .  That's when I traced wiring and realized that the 2.4K pull-up resistor never got installed, so we may be seeing the coil packs firing as a signal at the cam sensor.  Just to be sure the sensor wasn't reading the cam bolt, I made a sleeve to pound over the bolt head, shrouding the exposed "points" from the sensor.  Doing that actually allowed us to run the system on sequential rather than batch fire.  Today I'll install the resistor, which should clean it up 100%.  If it doesn't, I have a different sensor I can try.  


I'm also going to build a larger vacuum chamber to stabilize the signal from the manifolds to the MAP.  I figure about 10" sq. of volume will be enough to stabilize the Map, even though its working adequately now.  Its all in the details.  The guy doing most of the tuning is on vacation for a week, so I'll likely be buttoning up other details  as he doesn't want me screwing things up.  

  • Like 2
Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.