300zxls1

iTrader: (13)

Finally decided to ditch the IRS and go with a Fab9 housing and 4-Link setup/Mini tub. I plan to run in the 8.50's class, but while I am redoing the chassis I would like to upgrade to the 25.5 and be all set to 7.49's. Sense my 10 point cage is DOM mild steel I cant meet the 25.2.3 Chromo specs. Hense me building the cage to 25.5 specs

I just ordered the SFI spec book for 25.5 and should have it soon hopefully. But I have a couple questions for anyone else that did the 25sfi upgrade.




First off sense I have a 10point cage now I have a harness bar shown in this pic. All the pics I have seen of a 25sfi cage dont show that tube and it appears it would interfere with the funny car part of the cage. I couldn't find any shots of a upgraded 10point to 25 to see if they left the harness bar and just ran the funny car setup through it. Or if to meet SFI specs I have to remove it completly.

Here is a pic of a 25sfi cage which like all the others dosnt have the harness bar.
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I also plan to remove the rear main hoop supports and setting up the bulkhead like this.

300zxls1

iTrader: (13)

My other question was everyone that starts with a 25sfi cage weld the main hoop and a pillar bars right to the 2"x3" outriggers. Sense I already have the 6"x6" plates on the mating surface for all four points. Do I have to remove the plates and weld the cage directly to the outriggers or do you just weld the 6"x6" plates to the outriggers.

JL ws-6

iTrader: (50)

If you are going to back 1/2 the car you will need to do alot of that differently then the pictures you have posted. That's a start, but with the rear subframe that will go in that will hold all the rear suspension in, you will have to build off the main hoop to tie that into the chassis.

Honestly you'd be better off cutting what you have in the car out and starting from scratch, it will be easier then trying to add on to that and whatnot, especially if you are going to back 1/2 it. From the looks, is that a mazda? If so, the back 1/2 will come so far up with the length of the 4 link and whatnot in relativity to the body, that you will end up probably cutting everything out right from the seat back, so you'll have a substantially different bunch of stuff needed to tie it all together right.

Last mazda I saw done like what you want to do, pretty much ended up cutting the entire floor board out, and redoing it all, due to the position of the suspension, etc... ended up being a 90% tube chassis car with some front frame rail left, and there wasn't much of that left LOL.

Good luck with the project.... and get that plasma cutter warmed up. You're going to need it. And a spot weld cutter, and a sawzall, and a cutoff wheel, and an angle grinder... ya get the idea.

300zxls1

iTrader: (13)

I am having trouble finding classes that will allow me to race in. Sense the RX7 comes with IRS and I want to build a car to run 8.50's and dont want to stick with the IRS to do so. I want to build the car with a 9" and 4-link. I want to build the car to compete in the LSX shootout and it seems the only class I can enter is the rumble. But to make it easier for me to have a chance to fit into some local track events I plan to leave the stock rear frame rails intact as long as the 325's fit and if needed notch the outside of the rails. So its really more of a mini tub and 9"/4-link setup with as much of the stock rails and floor pan as possible. Instead of a back halved car with new rear frame rails and all. Below are some pics of a FC RX7 with a 9" and 4-link and stock frame rails. He put a 2x3" crossmember to mount the 4-link brackets. I may do a crossmember like his, but I will have to see how close the front 4-link brackets end up to the main hoop.





But like you said because the centerline of the axle on my RX7 is so close to the rear of the drivers seat compared to a F-body. And from the centerline of the axle to the front of the 4-link bracket I plan to use is 24". I will end up very close to my main hoop anyway. It maybe easier to just mount the brackets off of the main hoop like he did on this vette.

JL ws-6

iTrader: (50)

Both are possible... end of the day, it's gonna be alot easier to start without trying to make an existing part work on a build like this.

Not to knock what you're trying to do because I understand it.... but you're trying to do something with a car that's just a little bit too small to do what you want to do LOL.

The wheelbase, at the speeds you're looking at is gonna be a little hairy. Those cars are short by narrow in the wheelbase/width department LOL. Very easy to get a car that size out of shape at the speeds you will be looking at..... just something to think about.

You might, want to give that a thought before taking this project on.

300zxls1

iTrader: (13)

I understand what you are saying with the short wheel base and stability. Being the RX7 has a 5" shorter wheelbase than a Fox body but it has a slightly wider front and rear track. The short wheelbase is for sure a downside, but I love the cars and with the correct setup have proven 7 second 1/4 passes. I have done F-body builds before and I want to do some different and new. It may not be the best drag chassis choice. But I know it will be a blast to build and drive. Below is the rules for the Quicksteet 10.5 class from NED, my local track. Pretty much the perfect class for my build. Only downside is in the rules it says Import chassis are prohibited. But luckally the track manager said he will allow my car to run in the class. And I have seen other properly set up imports run in that class also.

Not sure if I will run in Outlaw street or Wild. But either should work out good.

Outlaw Street:
· Heads up
· .400 Pro Tree.
· Deep staging allowed.
· IHRA pro ladder (quickest to slowest; lane choice to the quickest car
in qualifying for first round - quickest car in previous round for second
round and beyond). In order to be placed on a ladder you must make
a run in one of the qualifying sessions. Late entries will not be inserted
on a ladder.
· Class designation – OS.

Wild Street:
· 8.50 index
· .400 Pro Tree.
· Deep staging allowed.
· IHRA pro ladder (quickest to slowest; lane choice to the quickest car in
qualifying for first round - quickest car in previous round for second
round and beyond). In order to be placed on a ladder you must make
a run in one of the qualifying sessions. Late entries will not be inserted
on a ladder.
· Class designation –WS

Vehicle Requirements:
Exhaust:
• Mufflers required.
• All exhaust gases must pass through the mufflers.
Tires:
• Maximum 33X10.5 slick. “W” tires okay.
• DOT approved tires are limited to a maximum size of 31x18.5-15.
Fuel:
• Race fuel, pump gas or alcohol permitted.
Engine:
• Must be an automotive type engine.
• No power adder restrictions.
• No powertrain restrictions.
• No cubic inch limitation.

Interior:
• All entries must have carpeting and door panels.
• Back seat optional must have passenger seat.
• Race style front seats permitted.
Chassis:
· Front End – OEM style front end is mandatory. Direct bolt-in
aftermarket and replacement front end and parts (Heidt's, Fatman, etc.)
permitted provided it is a direct replacement. Reinforcement of existing
stock front frame rails acceptable. Must retain stock radiator support.
· Rear End – Rear suspensions may be stock, ladder bar, or racing style
four-link.
· Back half type cars permitted.

Body:
· Must be full body vehicle and street appearing (working headlights, tail
lights, working brake lights, OEM dash and headliner. Chrome and
trim optional). No limitation on year of manufacturer.
· Must retain original appearances and profiles for year and make of
body.
· Stock firewall mandatory. May be modified for transmission and/or
header clearance.
· Lightweight body panels restricted to hood, bumpers, and trunk
lid/hatch.
· Wild Street, Fast Street, Real Street & Super Street: Forward facing
hood scoops permitted. Cowl hoods permitted.

· Maximum weight – 3,600 pounds (vehicles 7.50 and slower).
· Maximum weight – 3,200 pounds (vehicles 7.49 and quicker).
· Minimum weight – 2,800 pounds (Outlaw Street)
· Engine Containment System (diaper) mandatory. Belly pans acceptable.
· No delay boxes.
· No electronic or pneumatic throttle stops.
· IHRA Safety Rules in effect. All vehicles must pass IHRA tech inspection
for the elapsed time of their vehicle.
· IHRA Competition License is mandatory.
· IHRA Chassis Certification is mandatory for all vehicles running an
elapsed time of 9.00 or quicker.

JL ws-6

iTrader: (50)

Only problem I see with those rules is the stock radiator support... that's not gonna fly with about 3/4 of the cars out there, as they don't have them, they're moved, etc.

That, and it's my understanding that they are switching to NHRA this year (THANK GOD) so there's likly some changes that will occur.

Once they swap to NHRA, what the track really needs to do is look at the other tracks within the east coast, and get their 8.50 rules in line. If they want racers from other tracks to attend their races, easiest thing to do is to adopt the same rules, Englishtown, Atco, Cecil county all have the same 8.50 rules. NED needs to get on that and fast...

Lebannon, when I spoke with Howard Commander (track manager) I was told that at the larger events this year, they were looking at adding classes, 8.50 and 275 were both something that they were looking at, so you may have that option a few times a year as well.

300zxls1

iTrader: (13)

I just checked over the rules for E-town and there classes. If NED switches to there setup that would be great for me. The EFI Race series looks perfect for my car and I would have fun with that series. And its open to any EFI GM engine powered car. Top street would work also. Along with the 8.50 index if I ran a 275 radial instead of 315.

Then I can build my car the way I want with a solid axle swap, mini tub for 315's and a 4-link. And I can always run 275's to meet class rules if needed. But the EFI race series looks like it will be alot of fun. And E-town is not to long of a run from me from home.

JL ws-6

iTrader: (50)

The EFI series will be an etown only thing, that's run by barry @ QTP, and that won't be moving anywhere, at least I wouldn't expect it.

The 8.50 index rules that etown has, that are the same rules shared by cecil county and atco, and when the class is run at island they do the same rules, are what Epping needs to adopt.

Epping is somewhat stuck in their own little world up there.. once the NHRA transfer is done, they really need to get on adapting their class rules to come in line with the other tracks within a 10 hour range, especially if they want to see the racer headcount grow for the bigger events, which pretty much pays the bills/makes them $.... it's a no brainer to me, I'm curious to see what they do.

300zxls1

iTrader: (13)

Ya I knew EFI Race series wont move, I was saying I wouldn't mind making the trip to E-Town for some good events.

But it seems the E-Town 8.50 index or NED Wild/Outlaw street rules will allow me to compete if I build my RX7 even with a tubular back halve, 4-link and solid axle swap. I will just have to switch out tires sizes. So that works for me and if NED does adopt E-Towns and everyones elses rules then its all for the better like you said.

Krazy98Z28

iTrader: (12)

I thought no imports were allowing in NED's index program??

JL ws-6

iTrader: (50)

Krazy you know those guys up at NED, ya need to get them on adopting the etown style rules for their 8.50 index... if they do that the liklyhood of a better car turnout is pretty good.

The 9.50 rules, really should be the same thing, just slower really....... that way some of the stupid stuff like stock radiator support, no speedglass, that type of crap can get axed.

Krazy98Z28

iTrader: (12)

Bring the car and run, never seen anyone tech the car to the rules, i only do that for X275....

JL ws-6

iTrader: (50)

That will happen when it's done... I just don't know how much bitching I'll hear.

Krazy98Z28

iTrader: (12)

i honestly dont hear much bitching out of the group, the only complaints i heard were about throttle stops and no imports, other than that run the number and have fun