spanks13

iTrader: (5)

I finally threw all my pictures online so I figured I'd make a thread to track some progress.

I have a 1994 Mazda FD RX7 that has a 402 cube LS2 stroker with stock LS3 heads and a very mild cam. I originally completed the car in its first form about 5 years ago and have put over 20,000 street miles on it, along with beating the crap out of it regularly doing stupid ****. The car is pretty insanely fast how it sits with only 470whp and 450 ft lb, a stealthy 0 overlap cam, stock exhaust manifolds and cats, AC / PS . The car weighs about 2800 pounds, and has had various gear ratios in it with my settling most recently on 3.90 gears with a 25" tall road race slick out back. It rips.

The car is running perfectly and reliably, and is the best it has ever been. May of 2018 I purchased a low mile LS7 shortblock to try and **** it all up.



I set out on this idiotic journey so that I can go 200 mph in one standing mile, and I am pretty sure that maybe it will definitely happen. The car needs various upgrades and changes to both fit the dry sump system, and suit the higher power engine.

Among other things, it'll be getting the following -

New front end package including air intake, vented hood, radiator, oil cooler, and oiling system (dry sump for sure).
New dual 3" stainless exhaust.
It is getting driveshaft shop pro level axles.
It's getting a RPS carbon clutch.
It is getting a Holley standalone ECU, probably the Dominator
I might give the brakes an overhaul and put 18's on it but as usual that is at the bottom of the list.

The car has set FOTD at street day autocross events, and has been a fastest of 11.18 at 129.85 on street tires. I've never had a drag pack on it and really tried to launch it. It really isn't what the car is meant for...it is just an all around brutal car that probably doesn't need an extra 200 horsepower but that's what it is getting. It has retained everything that people praise about these cars, and then some with numerous chassis improvements and R-comp tires, and added 10 second straight line speed to the mix. I can't imagine what it'll be like with a 427 screaming to 8000 rpm.

I'll actually be a little surprised actually if I don't manage to hit 200 at the Texas Mile based on some other buddy's experiences with a similar car that inspired me almost 10 years ago now. If it doesn't hit the number it will definitely be damn close.

The engine is going to be a stock crank and rods LS7 with forged pistons, ported heads, and a huge solid roller camshaft. Everything in the list below I actually have and am working on putting together. Things I don't yet have are the Holley system and the dry sump, but I'll get there.

429" LS7 build
LS7 Block honed to 4.130"
LS7 crank polished and checked
Factory Ti rods in good condition and ARP bolts
Mahle PowerPak flat top pistons with 1/1/2 mm ring pack
BES 285cc ported LS7 heads, new factory Ti valves and Ferrea stainless exhaust
Comp Cams 258/272 .775/.756" lift 113 LSA +3* advance
Isky Red Zone bushed solid lifters
T&D steel pedestal mount adjustable roller tip 1.8 rockers
PAC 1238x solid roller valve spring kit
Holley Sniper low profile intake w/ Holley 105 throttle body
IGN-1A smart coils
Meziere electric water pump
Spoolin' 1 7/8" merge collector headers
Siemens Deka 60 lb/hr injectors

I plan on trying to run as close to 13.5:1 compression as possible. If I don't change anything from where I'm at, it'd be 12:1. I need to check my piston to valve clearance to know how much more I can cut off the heads.

At 13.5:1 through the Holley Sniper I expect to make somewhere around 760 actual horsepower, and am hoping to peak at about 7400, and run it out to 7800-8000 rpm.

7800 rpm in 5th gear is the magic 200 mph number.

spanks13

iTrader: (5)

So the big point of stress for a lot of people with LS7's right now is the titanium rods. The CRN coating for whatever reason is getting chipped away on the rod faces and putting titanium powder through the oil. The failure mode is still excessive heat and a spun bearing, but also sucks that you're pumping titanium grit through your engine as well.

I was very pleased with the condition of the rods coming out of the shortblock. Most of them looked pretty much virgin, and a few had some witness marks - but nothing that even closely resembles a coating failure.





The crank was also in good shape with no visible signs of wear or damage. It has since been mag'ed, checked for straightness, and polished with a clean bill of health.



The block did have a couple bores with some grooves that actually needed to be cut out. Nothing major, but it looks like some junk made its way through the engine for sure.



Same as the bores, the bearings had a little bit of crud in them. Probably what all of these things look like coming apart.



One surprise tool purchase I needed to make was a main cap puller for the LS7 block. I highly recommend this thing. Here's my dad modeling it lmao. The LS7 has billet steel main caps and have dowel bushings for alignment. They do not come off easily unless you have the right tool.

spanks13

iTrader: (5)

This was kind of crazy lol, but we drilled and tapped the block for oil squirters. With the plan to be running high compression with sometimes questionable octane fuel, and also hopefully run road race and full mile events, I wanted to help this thing out as much as possible.

Also with the dry sump I want to run some serious crankcase vacuum. It is a concern to run high vacuum as you lose the splash oiling on the pins and you might wind up welding a pin to the rod and throwing it out the block.

This was a nice kit, but rather sketchy lol. Thankfully...no harm no foul and the block is drilled and tapped for 8 squirters.







The hole is drilled into the main journal for oil feed, and an oil squirter jet is screwed into there. It protrudes through the other side of the web, and the angle of the jet makes it spray the underside of the piston. It cools the entire underside of the piston as it goes up and down the oil crosses back and forth.


So this was the final step needed before sending the block out to machining. Didn't exactly want to have the block machined and then break a tap off in the main web or something stupid....

We use Dougan's Race Engines in Socal for our race engines. These guys are CRUSHING it in trophy truck races right now. They pretty much have booked themselves solid with their own race engine program and have turned away outside work. Luckily my dad was able to call them up and they agreed to keep doing our race engines. These guys are the ones out front coming 1, 2, and 3 every event.

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Machine work wasn't too serious. We had them clip the deck to true it up, honed the bores to the new pistons, and they needed to hone the rods to fit the new pins. When I torqued the ARP bolts in the rods they didn't distort so the big end did not need to be machined. The mains were also true and did not need an align hone.

Everything is done with machining and we've started with mock up. Once everything checks out the rotating assembly can go out for balance.

spanks13

iTrader: (5)

I started mocking up the block the last couple weekends. I am pushing to get to the point of checking valve drop so I know my piston to valve clearance. That will tell me if 1, the cam fits, and 2, if I can cut the heads another .060" to bring the compression up where I want it. I may be able to flycut the pistons if I need a little more clearance, but we'll see. I have a nice engineering contact at Mahle that will probably answer me if I write to him.

I went a little crazy after I ordered the pistons...a small dome would've made things easier, but I got these for an absolute steal on eBay with one of those $100 rebate offers that were going on, and the pistons were already marked under summit pricing. A more race/custom oriented piston would've been triple the price, and I love the quality of Mahle parts. They make it very apparent why they're a top tier 1 supplier to the auto manufacturers.

I got a little stuck right before the moment of truth and haven't been able to get my answer yet regarding PTV.

Billy Godbold is a G and posted on his facebook (if you aren't friends and follow him, you should...you see some cool *** ****) about some prototype low shock solid roller lobes that he's developed recently. I reached out to him and he sent me his unpublished lobe lift and let me grind my cam from them.

These low shock solid lobes have slightly more lash than a LLSR which has some definite benefits. These lobes according to Billy have a "wider range of acceptable lash" meaning the cold setting isn't as critical, and if the lash does drift you're not tearing stuff up. With a LLSR you also sometimes have to actually preload the valves slightly when cold which isn't good for the seats if that clearance doesn't get taken up right away.

Comp has some lobes just like Cammotion they call them their hybrid hydraulic lobes...our 415 hydraulic cam drag motor has these "hybrid" lobes from Comp and they run awesome, but for a ground up solid roller design they can optimize a bit more. For a tight lash solid application, these will be the new hotness from Comp.

spanks13

iTrader: (5)

The cylinder headssssss...done by BES. BES does a lot of class engines and heads up stuff. I got the chance to buy these pretty much at dealer cost when a customer backed out...I was quite happy.

BES and CID also partnered to make the most seriously badass cylinder heads in the world for LS engines. Check this page out to see what level they're working on.

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I'll just...give you guys a few moments





Neat to see they unshroud around the exhaust valve which is the only real weakness of the LS7 head. The chamber hasn't been opened any more, but from a first look they need larger than a factory gasket, and should be biased away from the exhaust valve.









These might not be world beating record setting heads, but I think they hit a sweet spot that is pretty much perfect for what I'm doing. At the price point I got them I can't beat it. I don't need bespoke heads racing heads only to cap it off with a less than stellar Holley Sniper intake manifold.

spanks13

iTrader: (5)

To go with the heads, I have brand new Del West titanium intake valves that came out of an LS7 crate motor, and Ferrea solid stainless exhaust valves. I also sprung for the Isky bushed solid lifters. The bushings replace needle bearings in the wheel axle which have a habit of failing and destroying entire engines. The redzone lifters are designed for endurance race applications like 24 hour races.





How about a titanium 2.200" valve that is lighter than a 1.61" stainless valve? They are deceptively light to pick up and handle.





For the rocker arms I went with T&D steel rockers that are made for the stock eliminator class of NHRA racing. The LS7 COPO motors retain the cast in pedestal mounts. They're a very nice piece. The next step from here is having the heads machined down to accept a true shaft rocker, but that'd be another $2500-3000 at this point...I'll try the pedestal mount rockers first.

spanks13

iTrader: (5)

So after mocking up the short block, the cam degreed in perfectly and the piston was about .008" out of the hole which is very near where I wanted it for optimal quench. I will need to order a gasket for it anyway due to the larger bore, so once I get all the pistons in for the last time I'll be able to know the final thickness.





After all those steps I could finally get to the magic question of how much PTV do I have after grinding a huge *** cam and buying shelf pistons with small valve pockets...



And I got stuck and ran out of time.

The rockers don't clear the heads. Not a huge deal, but need to go in and pocket them a little with a grinder for more clearance.

rkupon1

iTrader: (3)

Awesome! I really like those rx7 platforms still. Can only imagine with an ls7. Gotta luv Titanium parts too. They still have that fancy look about them

bortous

What a great thread.
Really like the parts used.

91 Z28

iTrader: (3)

Awesome Ride!! They engine is gonna be something fierce

fnbadaz06

Bad *** !!!!

I'm also hoping to hit the standing start one mile at 200 MPH.....a very exclusive club to be in !!!!
Getting ready for fire up and break in for my 3.90 geared rear diff, then over to the chassis dyno for the tuning session.
Hoping my race weight comes in the low 2900-high 2800 range.

Darth_V8r

iTrader: (4)

Following. Thanks for starting this thread Spanks. Looks awesome so far

spanks13

iTrader: (5)

You should have NO problems haha. I’m going to just sneak in there if I get it.

I think you’ll be around 205mph which is very significant at those speeds.

grubinski

That's a *gorgeous* FD.

My Miata says hi ... it's a '96 (NA) with a 462rwhp (soon to be near 500 rwhp) LS3 in it. 2400# total weight.

The Miata is a bit jealous of your better aero ... no way I'd try to drive it 200 mph. :-)

fnbadaz06

The frontal area on my car is a bit larger than your RX-7 , so my calculations suggest it's going to be close....I don't think I have enough for a 205 though.
Depending on DA on the day of the event, I think I'll fall between 198 and 201.
If I don't make it, I'll re-cam the car with a solid roller which should give the HP buffer I need to reach 200

spanks13

iTrader: (5)

Yes I know the aero is a big advantage for me!! I couldn’t even dream of 200 without my tiny car lol.

I’d expect my car to be about mid 180’s with the same power if a c6z is in the 170’s. The motor I’m building I would guess to probably be a 190mph motor in a c6. I’ve struggled to find much data for NA mile passes.

What’s a 640whp c6z do in the mile?

spanks13

iTrader: (5)

I’m jealous of your light weight haha! I’ve had miatas they’re a lot of fun. Funny story, I wanted to swap an NB but found the FD was actually an easier and cheaper swap at the time.

The FD handles the power better than you’d imagine. It puts down power better than my c5z did. The suspension works really well.

The FD is a lot more playful than vettes too. My C5 I never wanted to slide around. It bit back hard. I can slide my FD anywhere at any speed. It’s not tried to kill me yet lol.

fnbadaz06

Here's data from a buddy who is close to 600 RWHP (SAE).
DA the day of the runs was in excess of 4600 ft , so true rear wheel that day was probably around 565-570, but he did have a tailwind to offset some of the power loss.

2009 Z06 HCI, forged bottom end, 91 octane tune, 591/512 rwhp/tq, Toyo R888R rears
Mojave .5 mile 4/15/18 - 158.0 MPH standing start
Mojave Mile 4/15/18 - 187.7 MPH standing start
Mojave 1.5 mile 4/15/18 - two passes at 201.2 MPH standing start. Only one of six cars that weekend to break 200 MPH, other 5 were FI cars.

Video: https://www.prescottvettesette.com/i...deo/Mojave.mp4


Mojave is at about 2600'elevation, DA during the 201.2 MPH runs was 4600' with 10 MPH tail wind.

when he runs the local NFZ 1/2 mile events here in AZ, he's gone low 160's. I had a bit more power than him (600RWHP SAE) and had a few aero tricks too.....I went 166.1 MPH.

grubinski

Agreed that the FD is an awesome chassis for an LS swap. Better than an Miata ... but I'm a convertible guy. :-)

spanks13

iTrader: (5)

Got my valve drop specs

At zero lash I have 105 clearance on the exhaust and 86 on the intake. Shooting for .080 and .060 when it’s hot with lash.

Going to cut .040 off the heads which should put me about 12.8:1 compression. Not quite as high as I wanted but it’s the space I’ve got.

I can now get the rotating assembly balanced too which should mean I’m done with machine shops.