SwimDude0614

Been quite some time since I've posted.

I'm David, head of the RX7 team at Team Rose Motorsports (TRM), a club at Rose-Hulman Institute of Technology. In 2001, the club bought an '85 GSL-SE. It's not quite stock anymore.

Engine mods (as far as I'm aware) include the following:

• Racing Beat Australian style intake
• Racing Beat header
• MegaSquirt ECU
• Street (I think) port - I know it does not have the stock port
• Oil injector removed
• 550cc fuel injectors
• adjustable FPR
• walboro 255lph good for 600ish hp
• upgraded corner seal springs

After having problems with it last year, we've FINALLY got it running again. We never did find out what was broken, but it's not broken any more.

So, my first question, does anyone see mechanical problems with setting the redline to 8.5k rpm? Whether or not we make power there isn't my concern - we have a dyno that can tell us that. What I'm really looking for is, what is likely to break at what RPMs, and what do we need to watch for. I've heard letting it run too lean can be a problem at high RPMs, so we'll definitely be keeping a watch on the wideband.


Also! Now that we have the engine running, we're going to be looking into items to upgrade next year. The car is an all-out autocrosser. My biggest idea is turbo. I want to turbo it. However, with all the engine mods we already have, I'm not sure if getting more power will help us all that much in an autocross???

However, suspension I'm pretty sure is already as good as it gets. Not entirely sure what all has been done to it, but I know it's a lot.

So, what out there is crazy and innovative that we could do? We're a bunch of crazy engineers with a fair bit of money every year at our disposal, so no idea is too crazy (some might be too expensive, but please don't let that keep you from posting).

Cheers!

David Zemon
B.S. Electrical Engineering 2013
Rose-Hulman Institute of Technology
Team Rose Motorsports Treasurer

Directfreak

iTrader: (2)

Simple.

Make the car in this thread:
https://www.rx7club.com/1st-generation-specific-1979-1985-18/2010-time-trial-s-nasa-national-champion-923396/

And add a moderate sized Turbo (for Autocross/quick spool).

Done.


Thank me later.

j9fd3s

iTrader: (3)

lol, df's on fire lately....

8500 rpm redline is ok, but after you find out it only makes power to XX, i'd back it down a little. for example if you make peak power @6500, then set the shift point @7200, and if you need to go higher occasionally, its ok. engine wears faster the higher you rev it...

on a stock gsl-se engine, the rotors are heavy, 3mm iron seals don't like high revs...

Jeezus

iTrader: (4)

You want your shift point to be when you make more power in the next gear than the one you
are currently in. No need to shift at 8500 only to have the next gear's RPM set you up past your
powerband.

SwimDude0614

Thanks all! And so, just to clarify, at 8500 we're not going to (immediately) cause serious engine damage? More wear of course, that I would expect, but not excessively so. I mean, we do have money in our budget to rebuild the engine from time to time.

Oh, and I checked today and we're getting 60psi of oil pressure at idle (~1500), 70-75 in neutral at 3-4k. Anyone know if this sounds like stock oil pump? I heard the turbos had higher volume pumps but I have no idea if someone in the past years installed one or not.

j9fd3s

iTrader: (3)

assuming it was built right, it can see 8500 hear and there without trouble. you do want to avoid 8500 every shift though.

70-75 is stock oil PRESSURE. tells you nothing about the pump. additionally the 86-91 engines have a different oil pump bolt pattern than the 74-85 engines.

these days people like to upgrade to the FD oil pressure regulator, its under $30 new from mazda, and it'll bump the oil pressure to 110.

SwimDude0614

what would we need to do to safely see 8500 every shift? this is an all-out race car (autocross) so we'll likely sit in second the whole time and sit at 8500 quite often through the straight aways.

why do we loose by putting in a higher pressure regulator? i assume there's a reason mazda didn't put that in all cars from the beginning?

j9fd3s

iTrader: (3)

assuming it is a GSL-SE core engine, here is the suggested list... its in the competition manual, which is @ foxed.ca the FD engines were actually upgraded to better than the competition spec which is circa 79.

the biggest concern is the apex seals, they changed from iron to carbon. the IRON seals are HEAVY so they do not seal well at high rpm. in the production engines mazda went from 3mm iron to 2mm iron, and then the rx8 is still iron but a shorter seal. the racers used the carbon, and then ceramic.

they bumped the oil pressure to 110psi (fd regulator)

they added hardened stationary gears (they are going to 9k at least, not a big problem actually)
they changed the bearings, again the FD spec bearings are better.

the oil pump has hardened gears, totally optional, as its the same as the gsl-se part, except it should last longer.
oil pan baffle plate, helps keep the oil around the pickup, these are CHEAP from mazda motorsports

mazda added a deeper oil pan too, and then dry sump, however the stock pan seems ok.

they undercut the rear of the rear main bearing journal on the e shaft, at high rpms it flexes, the symptom is high bearing wear on the rear half of the bearing, again the FD + engines have this done stock, i'd view it as optional.

trochoid

iTrader: (6)

If your going to track this engine at 8500 rpm most of the time, then now is the time to rebuild before the housings are trashed. j9fd3s has covered the mods quite well. I'd add a few more. Go with the lighter S5 rotating assembly along with the carbon seals and have it balanced. Do every oil mod listed in the Competition Manual.

Find out what suspension upgrades the car does have. There are some newer parts on the market from ReSpeed that may improve performance. i.e., coil overs, big brake kit, sway bars and rack and pinion.

SwimDude0614

Thank you all for the help.

Unfortunately, plans have made a change for the worse as of this afternoon. Our RX7 had a little encounter with a light pole in our parking lot. The frame I do believe is completely toast - most of the internals seem to be fine. We're now on the look out for a clean chassis, but until then we're at a stand still.

Rx Seven

iTrader: (12)

Well just keep your eye on craigslist or the for sale section of the forum and Im sure you'll be able to find another chassis at a reasonable cost.

BlackWorksInc

Have they really taken a turn for the worse?

When life gives you light poles, make full racing tube frames!

trochoid

iTrader: (6)

Post pics of the damage.

SwimDude0614

When this is all said and done (and TRM aren't pissed at me anymore) that's so going on my Facebook quotes!


By the way, anyone know if the suspension + drivetrain components we have/had on our '85 would bolt up to a 2nd gen? And, if so, would a 2nd gen do any better on an autoX track?

Directfreak

iTrader: (2)

Yes, Please post pics of the damage.

No, and No.

Unevolved

iTrader: (1)

So you're a college dabbling in motorsports? Look up the GRM Challenge. I run Texas A&M's team, and there are some other colleges participating as well. Hit me up if you're interested in the engineering side of things.

Kentetsu

Finding a clean shell shouldn't be much of a problem. You can start by contacting Billy from Respeed (forum name Bwaits_). He also has a lot of good suspension goodies you should look over. www.re-speed.com

The problem with running the motor to 8500 is that the parts you wear out are parts that can't be found anymore (at least not easily). I would set the gearing (or tire size) to ensure that you don't go over 7500, unless you are competing at the Nationals and have a huge budget. The benefits of the higher RPMs is nearly negligible.

Also, you're damn near local to me. Check out some of the videos in my signature line, and let me know if you have any questions. Also, stick with a 1st gen. 2nd gens are fat pigs. lol.





.

SwimDude0614

So much to reply to.

Grass roots motorsports is something we heard of earlier this year and sounds absolutely INCREDIBLE. I'd certainly love to try it, but I'd have to imagine it's higher risk than autocross. and safety is going to be key now. we'll talk about it, but i'm not going to be holding my breathe for it.

Kentetsu: thanks for the tip! I'll give them/him a call tomorrow and find out what he's got. Of course, the first step is someone has to buy my 20k mile Saab 900 (hint hint )

Assuming our club stays alive (that is in question - we'll find out tomorrow at an Officer's meeting) we will put the engine on a dyno over the winter and get her tuned up. if we don't see significant benefits to higher RPMs, I suspect we'll request money for a turbo next year. if we CAN get more power out at the higher RPMs, we'll probably go with all the mods suggested above, including hardened gears and the such.

and of course, by "we will" i mean "i will encourage the team" lol. I of course do not have soul control over what happens with it.

Pics:
They will come eventually. I personally don't have any, and no one in the club is posting any. we're keeping it quiet for the moment (so.. if you're from Rose-Hulman, keep your mouth shut.... lol. like you're from Rose). I would get some myself and post them here, but my left foot is broken from the accident and therefore can't drive my (manual) car.
I did go back to the building yesterday and take a look under the car. it seems the frame rail running along side the driver's door has been crumpled, along with other non-essential body panels and a couple suspension components.

The crash:
The car was wrapped around a lightpole. I came at it at (what i'm guessing was) 30mph and roughly 45 degrees. the pole first touched the car barely in front of the driver's side front wheel. The car pushed into the pole some, and caught it with the wheel. The wheel was them firmly shoved back into my foot-well (which is how my clutch foot got broken) and broke various bits of steering and suspension components. The front left engine mount (possibly stock? no idea what a normal rx7 looks like) was push toward the engine quite a bit. I think the engine is fine, except for one oil hose fitting that is now kinked. the wheel that came in contact with the pole is bent, almost certainly unfixable. fortunately, we have 7 more. the radiator also seems unscathed. tranny and drivetrain in general seem fine. the exhaust, which wasn't even installed for 24 hours, got crumpled as i slid off the edge of the concrete though.

Oh, and I did at least hit the pole hard enough to knock the light off the top!

Unevolved

iTrader: (1)

The GRM Challenge is an autocross and a drag race, I wouldn't say it's any more dangerous than what you're doing now. It's got a lot more engineering merit than simply building an autocross car, though. PM me if you're curious, I've done a lot of work on the administrative side of things.

j9fd3s

iTrader: (3)

good job! my friend did that in a dealership loaner car, they gave him another =)

SwimDude0614

Well, all these jokes just got a lot less funny.

Everything TRM is now frozen until Spring. Officers' keys have been confiscated so we can't even go to the building.

It's gonna be a loooooong, cold winter.

Directfreak

iTrader: (2)

That's probably because some @$$holes could not control themselves and wrecked a perfectly good GSL-SE while doing donuts in a parking lot.

Unevolved

iTrader: (1)

Having experience getting a school to back motorsports, I can't say I'm surprised. You got what was coming to you, IMO.

SwimDude0614

won't argue that. I was just hoping they wouldn't punish the whole club for my stupidity.

Unevolved

iTrader: (1)

That's what being a leader's all about. At the end of the day, it all falls on your shoulders.