rkupon1

iTrader: (3)

I gotta tell ya, i mite have looked all over craigslist last night for any deals on rx7 rollers,lol. This project is that cool

spanks13

iTrader: (5)

Lol it’s a sickness. I dig first gent Novas a lot. I like how you’re building yours but you’ve hinted at the cost and I shudder haha. In some ways I’m there with my car too. I’d want to build custom front and rear subframes, if not a full chassis, with road race suspension and IRS in the back.

There are some good deals it looks like on old restorations that would make great drivers now. I looked a few weeks back haha.

RX7’s have already gotten dumb and it’s really hard to find a nice shell now. Pretty much everything is going to need a full build. Part availability is also very bad for things like interior. I’m glad I started this project 10 years ago. I wouldn’t have been able to build it now.

spanks13

iTrader: (5)

That is awesome data! I feel like that is really fast for Mojave! I know it is slow up there. I drag race at Fontana and it’s like the armpit of Southern California. The air is terrible there, and Mojave has got to be even worse. Fontana is at about 1200’ elevation and the air quality is atrocious. You don’t go there to set records. Oh, and the track is uphill lol.

At 166 in the half did you ever run the full mile? I feel like 166 should be getting you close to 200?

You’re going to have so much more average power than me with your 468, but truly I can’t easily use more power in the midrange without a drag tire or maybe TCS. I’ll have a soft midrange by design, but hopefully extremely strong from 5500-8000. I don’t want to go full race car. I want to roll in how I drive it on the street and try to hit my goal.

In an age where forced induction rules, I still get super jazzed about the NA stuff. Like you said, NA 200 mph street car is very rare. 10 years ago it was impressive as hell to even go 200 at all. Now you can go 200 in the half with eBay parts lol.

G Atsma

To me, NA shows the true potential of an engine. Otherwise you just add more pressure..... lol

fnbadaz06

I haven't run any "official" 1 mile events yet, but I use a VBox to track changes in my performance envelope when I make any tweaks.
The 166.1 was at NFZ, and my VBox showed an absolute half mile speed (not averaged thru the traps like most events measure) of 166.5 MPH at 7380 RPM (on the limiter....I was logging with my HP Tuner Pro setup))
My "test track", I VBox measured my setup the weekend before the NFZ event to validate my aero tweaks I was using that weekend.
I was on a 285/40/18 NT05R street tire on an unprepped surface with .96% grade differential going down hill over a measured 1.5 mile "circuit".

1/2 = 17.26@165.7 MPH
1 mile = 194.7 MPH
1.5 mile = 204.7 MPH

spanks13

iTrader: (5)

That’s a hell of a test track!

Confidence inspiring for my goals too. Thank you for sharing.

gnx7

iTrader: (28)

We went 196mph over 10 years ago with a 595rwhp 440ci resleeved LS2 with TFS 235's and FAST90 intake in an FD and 275/35/18's all around... you really need to optimize aero to push into 200mph.... removing the mirrors gained us about 2mph. A real front air dam to keep air from going under the car would help a bunch..... and closing up the inlets up front as much as possible.

That is a bad *** motor you are doing especially the heads! Crazy solid roller also!

spanks13

iTrader: (5)

Mark! I knew you’d chime in eventually. You guys running Texas mile is my main inspiration. I’ve watched that video countless times through the years.

You went down there for that just after I bought my roller and it was one of the greatest thing I had ever seen haha. I remember you outran almost everyone that day. That’s how I learned about the aero advantages of the FD.

I’ve thought about incorporating at least a splitter with the new radiator setup, and hopefully tying it into some underbody panels - but that sounds ambitious.

gnx7

iTrader: (28)

Which event(s) are you planning on doing? BTW- I don't think I had ever driven that car before this event..... nor faster than 170mph (one day on the way to work in my own LS1 FD early am haha)

spanks13

iTrader: (5)

Texas Mile is the only event I know of without really strict safety requirements to go up to the 190’s.

Double06

iTrader: (1)

If you are running oil squirters you may need to change oil pump if you are sticking with the LS7 dry sump. The squirters obviously bleed oil so they have the C6 ZR1 pump that takes this into account as they have oil squirters. Kateck sells a good pump that has 20% more volume/pressure.

spanks13

iTrader: (5)

Good point for ls7 stuff. I'll be running an external pump, probably a 4 stage. Two pickups in the pan and one in the valley.

spanks13

iTrader: (5)

I’ve contacted our guy at Total Seal to see what he recommends with the Mahle 1/1/2mm ringlands.

I’m feeling like a 4 stage drysump and these Mahle rings is a bit of a mismatch. I do want to run crankcase vacuum. With the oil squirters I can run some serious vacuum, but I don’t think the Mahle rings would show much gain.

I don’t expect them to have a gapless ring at 1mm, but maybe their new gas ported rings with a lower tension oil ring.

http://www.totalseal.com/rings-gas-ported.html

84FSP

iTrader: (3)

There was an RHD Rx7 roller for sale on craiglist in lawrenceburg indiana. Really hoping it sells so I don't end up divorced putting my spare LS6 in it.

lstvr

Its the gearing that will need to be bang on, Ive done 202mph but the diff was a 3.08 and a five speed TKO box, you say you have a 3.90? What is your final top gear ratio? I was pulling 7400rpm at that, I went 199mph on 255.35-18 tyres time and time again, I swapped to a 265/35-18 and went 202mph first go. It was the revs/gearing that was crucial. Good Luck!

spanks13

iTrader: (5)

I've seen your threads. Your TVR is awesome! Wish we had those things in the US.

I have a 3.90 rear gear and with a 25" tall tire, 7800 rpm is the magic 200mph number. Fifth gear ratio is .74 for me which is probably the big difference between our setups.

It's a long pull in 5th, but there'll be just under 3/4 of a mile of track left to get there lol. I figure 1/4 mile trap should be ~140 mph and still pulling like a ****.

gnx7

iTrader: (28)

I think you should run the tire we ran back in 2009. 275/35/18 which is 25.58" tall We ran the Goliad, TX 1 mile event and looking up the altitude there it is just above sea level.... I'm sure corrected DA was higher; however you are going to be at probably a higher corrected DA so you need all the tricks up your sleeve possible. Remember every 1000ft of altitude gain you technically lose around 3% power due to the thinner air.

In actuality you want to bring a couple pairs of wheels/tires to change to taller/shorter ones and see how it affects the MPH and not be stuck with just one set. I don't think you are going to see 7800rpm from this motor being the fastest top speed. Shifting from 4th to 5th with .74 the power really falls off big time compared to a shorter 5th gear like a .80/.83. But given a mile long runway it is really about that aero. We ran a 275/35/18 up front.... I would run a 235 up front if you can justify it. A 275/40/17 is 25.66" tall

Use this calculator to play around with gearing/top speeds
http://www.gearcal.com/

I see a 3.31 gear in your future

spanks13

iTrader: (5)

Mark believe me I’ve wasted hours of my life on that site haha!

I don’t think you’re wrong about the tires. I’ve got a couple options there’s the 275/35/18 that I have had my eyes on, and also a 275/40/17 option that would go on my 17” rpf1’s. Both would gain me about 1/2” tire height. That would lower 200mph from 7800 to 7600 based on gearcal.

I think the 3.90’s will only help me. Due to the ratio drop on the .74 fifth I need to spin the bitch to damn near 8000 to get it to drop to 5800 on that shift. Any lower rpm and I do worry about the engine pulling hard enough out of the gear change at such high load.

I’d rather have 3.90’s to give me better shift recovery then try to pull 5800 rpm with 3.31’s or even 3.55’s. With the longer gear it’ll also be shifting at much higher speed which is exponentially more load on the engine for the shift recovery.

I’ll be dynoing the engine first. If the power curve isn’t kosher I’ll make a cam swap. I am estimating a power peak at 7400 and a tabletop to 8000 with the 258 intake lobe duration. If it peaks at 7000 and falls off hard before 8000 I’ll need to rethink things - either more cam, or if it made enough power - longer gears like you’re saying.

Your 440 will probably have 100 ft lb more than this thing will in the midrange. I’m going for a high rpm screamer and gear multiplication.

spanks13

iTrader: (5)

I got my PTV clearance measured and I won’t be able to clip the heads as much as I hoped. I think I’m going to max out around 12.4-12.5:1 compression. Only option from here would be a domed piston or fly cutting, which I don’t really want to do.

Think I’ll be let down by the lower compression? I wanted to target 13.5:1. Maybe a blessing in disguise? I should be able to run 91 octane without any additive on a mild tune, and run all the beans with flex fuel e85 or boostane with a separate timing map.


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 gas ported total seal 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
Meziere electric water pump
Spoolin' 1 7/8" merge collector heaters

spanks13

iTrader: (5)

So if I don’t clip the heads at all I’m at ~11.8:1.

If I cut them to the maximum I might eek out 12.4:1 that’ll have been cut about .045” total.

Since 13.5:1 is out of reach do I just run it as is and save a few bucks and any potential headaches of extra tight PTV and intake fitment issues? 12.4:1 is in a weird grey zone for 91 where the performance gains aren’t huge but I’d still need boostane or E to keep from rattling it to death.

The heads would be more useful for me in the future with the larger chambers.

Would this thing suck at “only” 11.8:1 compression?