Has anyone on here weighed...

[DR SCHNITZEL]

an fd engine with all the trimmings on and a V8 with all the trimmings?
 
What are the weight differences.

[BlitzBoy]

yes this has been done before, even with the twin turbos the 13B is still lighter , let me find the weights one second caller

[BlitzBoy]

Here we are

LS V8 (LS6 in this example) dressed = 208 kilos
13B rew dressed with twins = 150 kilos

so the 13b REW is lighter by approx 50 kilos, in single turbo form it would be slightly lighter still

[DR SCHNITZEL]

Just our mate off redline magazine reported that the rx7 lump is heavier than a V8. Would he be talking about another v8 ? LS1 perhaps. Or maybe out of his hat?

[BlitzBoy]

talking out of his hat.
The figures I have given you are actual real weights, taken by people who own the lumps and weighed them and GM data.

All the LS models (ignoring a iron block model) are aluminium, and weigh from 205 kilos to 215 depending on ancillaries fitted

A 13B fitted to the mentioned writer of redline and owner of a FC is lighter still due to the turbo and manifold weights being lighter then the rew twin turbo pack.

The lightest 13B is the one fitted to the rx8 115 kilos fully dressed (plastic intake manifold and no turbo and manufacturing differences in the plates)

[turbo boy]

So for the hijack, but what about an na 4rotor or na triple?

[BlitzBoy]

20B fully dressed is slightly heavier.

To negate some of the weight differences, the LS motors fitted to rx7s have the AC pump and system removed. One example Stock Rx7 touring 255 versus the same car (owner doing the conversion) with the LS motor fitted (AC removed) , the LS engined car was only 30 kilos heavier, but obviously HP per tonne the LS is much higher.

But of course if the AC pump was removed before hand before the conversion it would have showed up the 50 kilo difference as shown before.

There was only a slight change in difference to the 50:50 weight distrubution but not much in it.

But the cost of the conversion is high, Id rather keep the rotary a modify to 350bhp for much less money.

The conversion has it plus points, better MPG and more torque low down, but revs lower (you need to look at gearing to correct this so you dont lose top end speed)
But to me its not an RX any more, just call it a Mazda 7 lol

[jackaleks]

Wikipedia has some good info on the LS motors, like which ones are all ali and which are iron block + ali head. also stuff like stroke, bore and displacement as well as a bunch of other useless facts that only apply to piston engines

[turbo boy]

Very interesting, cheers for that

[DR SCHNITZEL]

I wonder then what my engine weighs with everything removed pas air pump, now single tub. compared to an ls engine with no emmisions (ready to drop in) You think 30kg less of maybe 40 to 50? those v8s look huge in the bay

[SiH]

Don\'t forget that for a 13b with either twin or single tub, you need to add in the weight of the intercooler and associated piping. For a single you need to add on the weight of a ex-wg and piping as well.

[BlitzBoy]

I would say single turbo FDs with all the AC and twin turbo gubbins removed is probably 60 kilos lighter then a LS

[Spartacus]

From what I\'ve read the average US swap (as they tend to keep their AC as the plumbing is much easier for LHD) works out around 20kg heavier all in. But saying that, while the conversion is being done it\'s all too easy to add or subtract weight due to changes that are not directly related to the swap, i.e. big brakes, smaller battery etc etc. When I did mine I started to weigh everything I took off the car and everything I put back on it but it didn’t last very long. Either way the weight doesn’t seem to make any difference so I don’t think it\'s really worth bothering about unless you want a super lightweight car in which case there’s always options to use carbon fibre bits.

[BlitzBoy]

I\'m aiming to trim down the car 1000 kg even after the cage is fitted, although the cage will add weight it will let me take out the safety bars out of the doors and trim the door weight off.

I think the point is you dont do a LS conversion to save weight, you do it for more mpg and low down torque figures and ease of maintanence.
Although if those guys in the US are saying only 20 kilos are added I think they are being over optomistic in their weighing in trying to win an arguement as actual weight figures of the fully dressed engines dont lie (50 kilos).

But horses for courses, people can do what ever they want to their cars.

But you cant beat that high rpm noise of a high powered rotary mmmm

[DR SCHNITZEL]

1000kg, wowzers! How easy will that be to acheive. Id love to get mine down to that weight. Is your car drag only blitz?