tomoaac

Diesel RX7

Ok what do you all think? I'm planing to get rid of the rotary engine and install a 2.4L Turbo Diesel.

I'm a Mechanical Engineering Student who loves the style and looks of the RX7 series 2. Infact i have two of them, One is coming up for engine rebuild and really fancy getting stuck into a project that will keep me busy and i'll get to use all my engineering knowledge.
The idea of having a diesel RX7 is all the cool but with 50mpg plus from a modern 2.4lt Ford turbo diesel. Out of the Ford transit van. Also using the gear box and a custom prop shaft.

140mph should still be possible Although it will sound like a nail!!

I know you American guys hate diesel but we love them in Europe, on the motorway nothing pulls harder then a diesel. The diesel is the inverse of a rotory engine, loads of low down torque but no top end.

Houstonderk

iTrader: (3)

There is a other engine conversions section somewhere else where you destroy rx7s like that.

Whizbang

ive poked at the idea before, seeing there is a mistsu-made 2.3L turbo diesel ranger at the junk yard. if the mounts are anything like the 2.3L turbo gasser from the SVO, then i would probably do it.

tomoaac

As long as it physically fits the mounts are not a problem. I can design my own and have them fabricated. In thoery engine height is the major concern. I would love to fit it with the rx7 hood intercooler, but just getting it in underneath the hood would be a challenge.
Good thing with a diesel is once the engine is secured and mechanically installed the rest is simple. No ignition to worry about.

I know you die hard rotory fans will hate me but i also have a rotary powered FC for fun the diesel will be for every day use. Fuel prices in the UK are a lot higher than in the US. and i love the novelity aspect of the build

fastrotaries

I agree with Ted.


and we don't hate diesels, some of the worlds fastest diesels come from the US. In fact the worlds fastest diesel pickup is from the US. We just enjoy cheap enough gas that we can afford 5.7-7.0 liter V8's as daily drivers.

Whizbang

honestly i love turbo diesel trucks...**** tons more power than a gasser. and hells of alot better economy.

Tyblat

then go to the other engine section and talk about it...

sudseh

so much hate from the rotards. gotta love it.

slo

iTrader: (1)

Ive been looking for a good diesel VW jetta for a while, I love a nice diesel. I can defanatly see the apeal escpecialy when fuel prices and fuel economy is taken into consideration. I immagine that it wouldn't be much fun to drive though. To reach anywhere near 140 with a diesel you will certainly need to change out the rear end. Ratios higher than 3.9 for the stock rear are very hard to come by. It would be no fun doing 80 on the freeway in a deisel at 4K rpm.

I wonder if anyone has made a serious attempt, to make a compression ign direct injection diesel rotary engine?

theantirotor

iTrader: (1)

how about this... you had chrome dubs on your FC, so you have no room to talk about detroying rx-7s. shut up kid.

tomoaac

Yeah the gearing is not an issue, The transit has a very long 6th gear designed for motorway cruising, most modern diesels do for that very reason. With the standard diff on the transit its turning about 2000rpm at 70mph.

Using y= mx where y = rpm and x= mph and finally m is the co-efficent

It can be shown that at 140mph the engine is only turning at 4000rpm

All i have to do is match the diff final ratio.

the Duratorq 2.4lt is 103kW engine (thats about 140 bhp), Get this though 375Nm of torque that comes in at 2000rpm. It will make the RX7 move qucikly in the standard trim, but it will not remain standard. The chip alone will give the engine an extra 20bhp. diesels respond greatly to ecu modification and the fuel systems are over spec'd

slpin

iTrader: (9)

diesel would definately be cool.
the most direct and wasy way would be to look for the GM 6.2L or 6.5, TD or not.
it uses the same mounts as the SBC, so one can just install it as if its a SBC swap, and brackets, everything for those are easily found.
the motor itself is also full mechanical, which makes swapping and installation easy.
TH400 will bolt up, along with the motor mentioned above. However, you probably want a different set of rear gears.... somethign in the 2.x range....

tomoaac

the 6.2 and 6.5 would make the job easy but they are just to heavy
Are they iron heads? the 2.4 is Aluminum

Plus not interested in an auto box, No one has autos in europe, I'l be using the transits box. 6 speed with a really tall 6th.

Rhode_Dog

Ever consider some of the diesel engine mercedes benz makes? I know they produced a 4 cyilnder diesel for the C class in europe, not to mention the pre bluetec inline six was a pretty stout motor.

tomoaac

Cost and avalibilty are a key factor.
Ford transits are everywhere and parts are cheap, so the benz would be nice, it would have to be the 4 cyl the 6 would be too long and throw out the weight distribution.

slo

iTrader: (1)

That was kind of the point, try finding a 2.xx (assumption here) ratio to fit in the stock rx7's rear end. And I'm sure it would not be fun at all to drive with the rx7's stock rear ratio. which means the added expense of swapping the rear.

, Those engines are close to 1k pounds.

Link, http://www.65ldiesel.com/page/page/1271489.htm

"lightweight at under 1K pounds"

tomoaac

Final Diff ratio (dont need anything like a 2.xx)

Like i've mentioned before, i'm using the gearbox from the transit too, The transit has a 3.75 rear diff, with overall wheel diameters nearly exactly the same as the RX7. I've already worked out that at 140pmh the engine in the transit is doing around 4000rpm, that is because the gearbox has a really tall 6th gear for motorway crusing.
Using the standard RX7 diff 4.1 i'm looking at 4375rpm at 140mph, which is pretty perfect as that is roughly the engines redline so could see a top speed of 140mph.

2.xx final ratio is way off when using the 6 speed box.

slo

iTrader: (1)

You didn't mention that before. a 3.9 should be easy to find.

ronbros3

WOW!!! you guys are so far out of reality, I have been a Hi-perfomance Diesel engine mechanic for 25yrs. and you had better come up with something better than whats posted here. I have my own ideas! Ron

slo

iTrader: (1)

Care to share what your ideas/problems are? I don't have any plans on converting an RX to diesel, but I am very interested in diesel performance in general.

tomoaac

Ron enlighten us,
You can't come here with that statement and not hint at your plans.
So far my project is in the concept generation stage, I have the FC awaiting a rebuild and I can aquire the 2.4 TD with 6 speed box.
Everything tells me the two can be mated and would produce a daily drivable FC with adequate power around 150-160BHP;

What your concept Ron?

capn

That would actually be cool, there have been some people that have poked around the idea of a diesiel. I say go for it, if you are looking for something to drain you of your money and time then putting a engine no one has done before will do the trick.


I say go for it!

capn

you know what Im gonna bring this back, I want more info on this.

putting in a Turbo 4 diesel would be a pretty neat swap, there are also more and more TDI engines now. I think it would be pretty sweet to see a VW 1.8TDI or maybe the audi V8 TDI or just something along those lines. More torque is always good and you can be also run Bio diesel.

So more info, like do you need to switch fuel pumps, new fuel lines? so on so fourth.

Wanktastic

Because diesel is much thicker than gasoline, you would need a new fuel pump, most likely new fuel lines, along with a new tank. The real trick I foresee is finding a RWD transmission that will bolt up to a TDI motor. If you can figure that out, then the rest becomes very simple (relatively). In theory, it should be no different than swapping in a V8 like everyone else does.

SilentRun7

iTrader: (1)

Gas fuel pumps work perfectly fine with #2D running through them, in addition to the fuel lines and fuel tank. However, if you plan on running significant percentages of biodiesel, the fuel lines might need changing depending on what material they are.

There are other vw/audi based engines that have appropriate RWD transmissions, such as the inline 5 cyl 2.0L IDI, the 2.5L tdi, or the bulletproof and silky smooth 2.4L inline 6 IDI engines. Some folks are running more than 45 psi on the latter engine, and there is a 450whp model running about Europe (I believe Norway or Finland) that still gets mid to high 40's for MPG...