Rob Dahm's overhyped underperforming turbo 4 rotor RX-7 build
 

So i figured i would finally start a build thread. I've been making major updates on YouTube but i hope to fill in the details here. After about 2 years of obsession and feasibility planning i decided to build the most insane street RX-7 ever.

As many of you know i own a legendary car already, and before 2 people start grumbling, it was legendary long before me. TurboTommys 3 rotor turbo rx7. The problem was i didn't build it. I just improved slightly upon it. I took the car down to the frame and rewired the entire engine bay. She purrs better than ever. Buy she still wasn't my creation. and no matter how much you credit the inventor, it doesn't feel the same.

The car isn't exactly my style. It sacrificed too much street ability for raw drag racing power. I still love it dearly. But as i went to improve on it, i decided it was best to start fresh.

Its been along time coming. and it still going to take a while more. This was never meant to be like my 3 rotor, I've had a vision for the last couple years and i intend to carry it to the end. Uncompromising superlative performance in the spirit of Mazda's vision for the RX-7

A couple goals of this project:

1) carry out the vision I've had for the fastest street rotary engined vehicle

2) get my hand dirty from the start. I am in no way dissing anyone who buys a built tuned engine from PPRE. with the NZD to USD, its financially intelligent and a no brainer to go that route. But this build is for my own satisfaction. I want to start with circular pieces of metal and take pride in seeing them spin with my direct involvement.

3) Get some of the brightest people involved. If this car was my biological child, Abel Ibarra would be the godfather. Hes been involved since day one and we legitimately talk every night on issues and problem solving. He has put down horsepower i never have. He has accelerated much faster than i have. Ive also got some other infamous people involved in the project but i cant disclose their names yet.

4) Live up to the hype forced on me by YouTube. I like making videos. but i get impressionable teens who see the 3 rotor shooting flames and assume I'm the fastest most insane rotary guy ever. That title is more for the people producing results. Len, Tommy, Roan(awesome seeing the car back on the strip) I enjoy the theatrics, so why not own it? High hp numbers, massive single turbo that drops jaws when a more complex twin turbo system might perform slightly better. And so on.

My goal is to entertain. And i certainly hope my recent GTX5533R video helps illustrate just that.

;) welcome to the fun! You're build sounds amazing. Cant wait to get these cars together for carnage time!

Goodluck. Looking forward to seeing updates

You know it! I feel like between our builds we will showcase some of the best facets of street rotaries.

I found your youtube channel a couple of years ago. I look forward to learning more details about the car.

i didnt know your car was tommy's car..gee i remember his launch control was shaking the whole nantalla village. I was in my room and he was on the other side and with that rev limiter i thought there was a machine gun in the room lol... that was back in 2010 maybe?

i wish you great success my friend..

Subscribed!

Hey Rob!

Should be an interesting build! Are you pulling the 3 rotor out and putting the 4 rotor in, or are you starting with another car?

What are you planning for engine management?

Really hope to see you again sometime at Deal's Gap!

Dale

subbed.

always enjoy your videos Rob! hope you get the v12 figured out too

Crazy, i've been wondering if you were on these forums. Looking forward to seeing the nitty-gritty on here. You don't update on youtube enough ;)

Greetings Rob from SE Mi. Loved the wonderful videos on the 4 rotor delivery drama. I felt your pain, let laughed a lot (not at you). Glad you have this moving forward!

Looking forward to seeing this built and done some day (MCMC, Lingenfelter, Woodward, Pastiness, or ???).

Well this thread is boring :p

Jk

Looking forward to progress!

-Nick

You guys' Rotaries are going to roar this world.

:popcorn: :popcorn: :popcorn:

The 3 rotor remains untouched. The shell is in bad shape. Just a rough car all around. Functional but rough. This is going in my 2 rotor montego blue rx7.

My budget for this build is exceeding it's original 100k plan. I'm okay with that, but I may sell the 3 rotor to help balance the budget. Hell, my transmission core alone cost me 5k more than the whole 20b car cost me Haha.

You considering selling the 20b...no longer will I be able to listen to "sail" again...

But should be interesting to see how this build comes.

But seriously, sell the lambo. Nobody likes those cars anyways :p

That was the year we met too! I remember staring at his car drooling but not thinking much past that. The anti lag is pure insanity on that car. Same one that knocked people off the wall at my drag strip when i was launching it. haha

Sweet! Glad everything worked out for you with the UPS nonsense....

well not worked, out... but .... at least you got most of it back right?

Anyways, subscribed!

Sub'd to watch Rob lift up his turbo on some more videos

what transmission are you putting behind the engine? sounds actuated sequential.. sounds expensive lol. best of luck on the project. we're all following closely and wish you the best.

Can you elaborate fastest street rotary engined vehicle? I can name many fast rotary powered vehicles on the street including my own.

No pictures yet?! Subed!

I'm actually wondering this as well! I'd also be interested to know the complete rear end setup that will be going behind this monster of an engine.

-Skeese

How many pounds of pressure are you running on that car? How many are you willing to run? Hell my 3 rotor is a fast rotary powered street car. I'm not going to spend 150k on a build to make a car slightly faster than it haha

I'm not going to make statements like that without being able to measure and quantify. It will break the fastest 1/2 mile record for rotary engine street cars. I dont mind getting beat after. i just want to say i did something notable. Obviously a drag car could line up the half mile and coast almost the whole way to a record, but thats not what my intentions are for this beast.

In a less quantifiable sense, i want to take the car to TX2K and make an impression out there. Knock out a couple TT Gallardos. That would make it so enjoyable

A large part of it is proprietary. I have been designing it for several years. BUT the trans is a sequential dog ring engagement 6 speed transmission at the core. :-D

Ive been filming and documenting the process so after all the hype dies down from the launch, i want to make the behind the scenes videos.

Makes sense.
Just wasnt sure if you mean 1/4 mile or road race at the ring.
Would be neat to see how it does in the 1/2 and 1 mile. Should be nothing short of amazing.
Tx2k would be a blast to take on some of the tt exotics.
My car fine where its at. Im happy just looking at it to be honest. My goal was to build my dream car and be done.. Time to spend more time with the wife and kids then build the first gen maybe 4 rotor down the road.

Part of this build is at my house. aka house of never ending builds. haha .:cool:

so pumped to see this build!

Most of the seriously built cars doing these airstrip events aren't really power limited; they are traction limited. I'm sure this car will make a lot of power.

It would be a dream to have someone represent rotaries properly at the texas mile. I think you would need about 3000whp to make a huge impression with e85 or methanol with our FR platform. If you decide to make it, I'm sure you'll have tons of rotary love and support. I personally would take a week off to see you make this run.

sweet! finally glad to hear its coming along, been waiting for this build , good luck on the build

The Texas Mile really is a hell of an event. Like ZoomZoom said, the cars suffer from lack of grip at speed, but the majority of them are pushing over 2k WHP! I would love to see a strong showing and there presently is not a rotary powered vehicle record, so Rob's record could be the first to make headway in this realm.

Just as examples, I pulled two articles on some Texas Mile cars that are seriously fast.

This GTR
2000+HP R35 GT-R Specs - Texas Godzilla

This GT40
M2K Motorsports 280 mph Ford GT

Based on Rob's turbo choice and the airflow potential of a 4 rotor, it should make at least 1200 WHP at around 29 psi, which is astounding to say the least.

Here is the compressor map:
http://www.atpturbo.com/root/maps/im...55compress.jpg

I would think he needs at least 2k whp to make an impression. 2.5k whp to compete at the top level.

Figure out the power to weight and you have your answer given he can put down the power with a RWD car in an event mostly dominated by AWD cars.
This year Slipstream is trying something different with the classes here on the East Coast. AWD and RWD will have different classes and there are classes based on weight. It's not completely broken down to several classes it's mostly been done to seperate the GT-R's. The N/A class is interesting. If the 4 rotor were N/A it might be able to dominate that Attachment 610966

What do you know about the classes in the events you plan to run Rob?

Well, assuming that the car weighs 2800 pounds wet and has 1200 RWHP, that puts it at a power to weight ratio of 0.43.

A Nissan GTR at 2000 AWHP has a P/W ratio of 0.5

It also has the added benefit of traction to go with it. That's why they dominate, but provided the FD can hook and maintain as much power through a run, I don't see why it couldn't put forth a strong showing. The main issue I could predict is keeping the rear planted through a run and managing the torque of the engine as it spools up.

There is an article on MotoIQ where their RWD S13 Nissan with a 1.5L SR20 variant had difficulty keeping traction at speed. Now they were running on the salt and they run very skinny tires, so that is obviously a contributing factor. That being said, a 1200 WHP FD is a rocket ship at spped, hell even at 500 WHP people get into trouble.

I know something abut the classes... whatever they are will change, and change again before the build is done. :gwink:

1200hp is a TT gen 2 viper on low boost. (that you can buy for around 50-60k)

a Friend of mine just ran 214 at the Arkansas mile in his. (the only one in the top 10 that's not a "shop car")

https://www.usmileracing.com/full-results/?event=20

i think a TT viper is the proper "bench mark" for a turbo 4 rotor.

Should be a nutty combo when finished. You need boost by gear dialed and TC to even try to manage that power. The FD has great aero and small frontal area on its side. The TX drag strip for TX2K is super well prepped with VHT compound. So that would be the best place to run for a RWD car for sure...

Most of the airstrip events have poor surfaces with pebbles/dust etc and zero VHT anywhere. I can't put down full power until 4th gear if not 5th. I can spin the tires in 5th gear at 180mph big time. I only have boost by gear. 1st gear 8-10psi (750rwhp), 2nd 10-12psi (950), 3rd gear 12-14psi (1050), 4th around 18-19psi and 5th 20-22psi. Traction is the problem.

A vented hood helps with stability big time. An undertray needed also. Smallest width front tire allowed. I run a 235mm front and 275/50/15 M/T et street drag radial for 1/2 mile. Any other tire doesn't put the power down very well. There is a trade off between tire pressure being low for max traction.... Or higher for more stability at 185mph+ And less traction. I prefer more stability. Also after your run don't stab the brakes .... Ease into them to not unsettle the car.

Awd High HP GTR and Gallardos you can't compete unless they are low HP builds. They can put down the power everywhere. I only beat RWD converted TTGallardos ;)!

Bingo, setting up for Boost by Gear with traction control via VSS and ABS sensors, vented hood, and splitter, full body undertray, for these very reasons. This chassis already spins like a maniac above 700rwhp, traction/control of the car > hp at this point

Yeah agreed. But with a grassroots start, i can put a decent show, set a rotary specific benchmark, gain some traction (lol) to afford turning the boost up. I dont intend to come out there guns blazing and set the actual record. But to have a rotary play with the big boys makes me feel like i added to the community somehow.

So you are hearing it first here. My transmission is in the process of being built. I am doing some top secret things to it but the core box is a Holinger RD6 ( i love the initials) 6 sp dog ring engagement sequential transmission with pneumatic shifter. although im making sure i can swap between teh two. i just dont know where the shifter will go and i dont have to worry when its all concealed in the drivetrain for now. Gearing the car for 220+ not sure of my final gear ratios just yet. but an aquantance just set the standing half mile at 240 in his gallardo so thats a bit higher than i was intending to gear it haha. we shall see.

Regardless my intention is to get some mainstream attention to help afford pushing this platform to its limits. I wonder how much horsepower you can put to the rear tires before its absolutely too much in each gear.

What do you think about how well the 26B could do in the N/A division? Seems possibly the best place for the motor.

need good areo to avoid going airborne

Other wise, this happens.

Sounds slow! ;) Tell Abel to hurry up!

If you can crack 200mph being RWD you should be happy. 220mph is a pipe dream. There is a lot more to it than just raw power.......

Kong Chang's 1200rwhp+ 996TT RWD conversion Porsche with a sequential gearbox did a 205mph best pass at the Shift Sector 1/2 mile event; however there really isn't much more left in it simply due to not being AWD. His car has an advantage with the weight being all over the rear tires vs. our front engine layouts. That track is not prepared at all compared to a TX2K drag strip. I don't see a 2wd car going much beyond 200mph.

The Hollinger transmission is no joke. They are creme de la creme. Best trans out aside from the PPG sequential T56 as far as holding power in that configuration.

Here is a 1971 Triumph with radically altered front end doing 387mph with a FWD turbo V8! Stupid fast..... just for entertainment! Small frontal area FTW

As we get closer to unveiling the concept at SEMA, i have some shiny expensive things to share. The Holinger RD6 dummy box has been in for a bit. I got the FD bellhousing adapter machined for the RD6. Its a piece of art in its own right. We also had Promaz machine a custom steel bellhousing based off the turbo 2 design. That should hold the power, protect my legs, and make room for the massive clutch. It is billet steel and only weighs 23 lbs.

The machine work is what makes this car so unique. I have quite a bit more being machined in North Carolina right now, but its cutting it close to the deadline. Ive had this concept planned for 2 years but like anything it doesn't really take off until the last second.

Good God Rob... you just set me back 10 years on my build... back to the die grinder I go.

My goal 2 years ago was to make the most insane legendary car. I didn't realize how expensive that would be. Haha. I can't have everything.

It is pretty cool as I explain my vision of this car to vendors they have given me extra support and put their own twist on solving the challenge at hand.

I didn't mention it here but I'll be unveiling it at SEMA in the Garrett Turbo booth. It won't be a running car lol. But it sure as hell will showcase the unique things I'm doing to support and utilize the amount of hp this car will produce.

I've been tight lipped this far as I don't want to make claims and come up empty handed. That's soul crushing. But at this point I can safely say all that machine work pays off to make this a balanced rx7 on steroids.

billet block eh?

Not the block. The front cover, bellhousing, and transmission adapters yes. Not courageous enough to experiment with billet irons or housings.

billet blocks
 

the are proven, that is what all the top rotaries setting world records are running. Cars like Loquito Killer, Major League, PAC ect are all running all billet or most of the parts are billet. congrats on the progress.