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280z FP Build


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Mid season update! Just been fiddling with the car, my co-driver and I are starting to work out some of the body roll, hopefully some beefier springs will solve some of the issue, or at least give us an actual baseline to start with. Upping from the AZC mystery 200-300# something springs to 400# front and rear. We've been lifting wheels in the slaloms and through hard banking corners. The tire can/should hold 1.8g but we are struggling to get and hold 1.3-5. Here's a video to for you guys, this run was good for top time at our SCCA club event. PAX-wise (for all you SCCA calculator racing fans out there) this time was good for 9th overall. I feel like I'm consistently about 2-3 seconds slower over a 60 second run compared to the fast prepared guys in the club. Bringing the car to the national tour stop, so it will be a good benchmark!

 

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Video from last week at Oregon Raceway Park. The lap in this video is a 2:06.xx, guess where I lost heaps of time! I ran 3 2:02.xx laps in my last session, no video, only data. Excited to go back and do it again!

 

Edited by Ben280
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  • 2 months later...

Sad news everyone! My L28 has finally broken on me. Cause of failure has yet to be determined, but it is out for the rest of the season. I think its cracked compression rings, or something oil related, a tear down will tell the whole story. The car will miss nationals, but I'll still be going, just in an STS Civic! I'm also calling and emailing engine builders. if I have to rebuild a motor, then I'm going to rebuild a motor worth owning. 

 

I've got some video from this past weekend, but haven't downloaded it yet, so heres some footage from the SCCA National Tour stop! Combined, my runs were good enough for 4th place in XP. 

 

 

 

Looking forward to making some more mods this winter, and adding hopefully double horsepower to the equation! 

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Upping from the AZC mystery 200-300# something springs to 400# front and rear. We've been lifting wheels in the slaloms and through hard banking corners. The tire can/should hold 1.8g but we are struggling to get and hold 1.3-5. 

 

1.3 to 1.5 may be all you can get if the pavement is not really clean and rubbered.  It may also indicate that your tires are getting too many runs on them.  You'll need a clean surface and the tires up to temp to ever see numbers over 1.5.  When a bunch of us used to run our cars in prepared classes in Medford, OR we found that most cars worked pretty well with 550s all round, which is assuming a weight of around 2K pounds.  The higher spring rate will help put heat into the tires.  I know there are many ways to skin a cat but that resulted in a FP car that took many TTOD and was top on top of PAX.  To put that in perspective on the Fall Enduro course it would now lap in 44.75 seconds.  Not sure if that helps if you haven't been there with how the car is currently configured.

 

Cary

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I think it was old tires, but the springs are definitely helping. 

 

Don't remember my lap times from when I was at the Enduro in 2013, but that benchmark is a good piece of info! I end up looking at a couple of the other prepared car drivers regionally, and comparing PAX time. Maybe next year I'll be able to get back down there!

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  • 4 weeks later...

Picked up a new (to me) motor today! Rebello built 13.8:1 with Carillo running gear the original dyno sheet from 3 years ago shows 282hp at the flywheel with SU carbs. Hoping that EFI/ITB's and tuning will get it into the low 300's at the flywheel, and 270+ at the wheels. 

 

Excited to get my ITB's finished up and synced! Need to do a bit more research on tuning for pulse length before I throw down money for velocity stacks. 

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Hoping to get some good results next season Tube80z! The suspension should hold up, need to do some swaybar tuning next year, and likely a shock upgrade will be in the works soon. 

 

Clarkspeed, I'm looking into that possibility, it would certainly be cheaper and easier for intake tuning!

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 Tube80z! The suspension should hold up, need to do some swaybar tuning next year, and likely a shock upgrade will be in the works soon. 

 

I have no doubt it will hold up.  What I meant is to take it to the next level it's going to require some changes.  A big one I haven't seen anyone try yet is reducing the front scrub radius using struts.  I'm cheating and using a-arms.  Look at what BMW does with dual lower ball joints.  Or Ford and GM with a strut that has an articulated upright on the end (superstrut).  Technology has moved on, fortunately in prepared you can bring your car up to date.  That's what it's going to take to take the fight to Gorman's Porsche or some of the other cars.  As they say the first few seconds are easy.  It's those last few tenths that get very hard.

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I have no doubt it will hold up.  What I meant is to take it to the next level it's going to require some changes.  A big one I haven't seen anyone try yet is reducing the front scrub radius using struts.  I'm cheating and using a-arms.  Look at what BMW does with dual lower ball joints.  Or Ford and GM with a strut that has an articulated upright on the end (superstrut).  Technology has moved on, fortunately in prepared you can bring your car up to date.  That's what it's going to take to take the fight to Gorman's Porsche or some of the other cars.  As they say the first few seconds are easy.  It's those last few tenths that get very hard.

 

Ahhhh yes, I see what your saying. Yes the Montgomery/O'Gorman car is a mighty foe, don't think anybody besides Kiesel has been as dominant in a class. There was one guy in FP running a SLA front end and I wish I got a better view of it. Might be a good time to go back to school and get an engineering degree!

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  • 1 month later...

Halloween update! Been progressing slowly, everything is out of the car and ready to slowly start coming back together. I noticed a small leak out of one corner of the fuel cell, and needed to investigate. Got everything apart and pressurized the bladder. Sprayed throughly with soapy water and couldn't find anything. I suspect one of the fittings wasn't tight and fuel could leak out in between the bladder and steel cell. While the cell was out it is a good chance to investigate my fuel starve issue. I've been using a ford focus SVT fuel basket, which has a small built in surge tank. I think the pickups were clogged and it wasn't refilling the tank, because at free flow the pump was pretty weak. Took about 15 minutes to fill a 5 gallon jug... I jumped the gun and was looking at new pumps, but decided I should flow test the pump outside of the fuel basket. Night and day difference, was able to do a gallon in 45 seconds, so just under a 255gph pump. Looks like that will be staying with the car. I ordered a Holley Hydramat to replace the teeny factory pickup. It's a 3x15" version, and should let me run below 6 gallons in the cell pretty easily.

 

Working on my "To-Order" list so I can get everything headed back into the car! Right now it looks like a new shifter assembly for the 240sx trans, velocity stacks and a filter. 

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  • 3 months later...

Oh man, where to start! Left you guys hanging here, and months later the car is back together and running! Lots of stuff happened with no photos, but I’ll try to give you the high points.

 

We left off when the original 2.8 had blown up and I had found a new engine. A 13.8:1 Rebello auto-x engine in a friends car and 240sx transmission was going to make an excellent upgrade to this machine!

 

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A big fixture of this rebuild was the ITB’s! Thanks to the HybridZ classified section, I scored a set of OER ITB’s that used the FC RX-7 injectors that I was using already. I had to get ahold of a new manifold, and sourced a Kameari unit from a yahoo Japan auction. Once I had that piece I was able to get runner lengths and found that the 75mm Techno Toy velocity stacks were going to give me a good powerband with optimal induction wave at 5500rpm.

 

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My excitement to blow up the new engine by not running filters was super minimal, so I was off to find a good filter scenario that would with with the fuel rail. Most of the traditional carb filters have interference issues with the rail, and I didn’t want to run the sock filters that most ITB’s require. ITG is a top name in the filter game, but their traditional filters weren’t going to work. Luckily some searching revealed that they make a “Sausage” style filter, which is curved for a more clearance. I also found a company in the UK called Reverie that makes carbon airboxes for formula cars. Fortunately for me, lots of the stuff they make fits on inline 6 formula cars, so I was able to pair up a couple custom UK pieces to keep this engine rolling!

 

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Also had to figure out getting MAP signal from the ITB’s. The Megasquirt ITB tuning mode uses MAP pressure up to a certain percentage, then switches to AlphaN/TPS position. I got ahold of a vacuum log/accumulator that I can run all 6 ITB’s into, and get a good MAP signal up to about 30-35% throttle.

 

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Was also able to spend some time working on the exterior and maximize my aero allowances! Rules say I get 10” of spoiler, so I’m taking everything I can get! Using NASCAR truck spoiler adjustment rods, pretty excited about how it turned out. Also added Techno Toy Tuning tow points for ease of recovery! Not that prepared cars ever break down ;)

 

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Finally got the whole rig running over the weekend, and it’s idling nicely! Syncing the ITB’s was an essential step, needed to get a snail gauge on it and get everything working well.

https://youtu.be/MS7ahQA511E

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I've been looking at buying that same Reverie item - I imagine the quality of quite good? The price is certainly very fair right now with the exchange rate!

 

Really like the look of the sausage filter too. I bet it makes it much easier to maneuver the filter on and off, while also giving more clearance.

 

Great job!

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The Reverie piece is really nice. My one issue is that the #1 and #6 stacks sit really close to the edge, and on mine I had to file down the inner radius to get them to sit flat. As a general work of caution with it, make sure you have a way to get to the velocity stack hardware! I had to use allen button heads with a ball ended allen wrench.

 

The sausage filter is awesome and very easy to fit! I'm excited to do an on/off dyno run with the filter. 

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