LS1 V8 fd conversion progress thread

[CRAIG R]

Cracking thread ,keep it coming mate;)

[Spartacus]

Quick update, all the back subframe including the differential and suspension are now back on the car.
It\'s now time for the same treatment at the front, which will include a total strip down, bead blast and rebuild of the suspension with all new bushes onto the Hinson supplied modded front subframe.
Here’s a pic showing the differences between the old and new subframes. I found it a lot cheaper to buy a subframe in the US and have it sent to Hinson’s rather than ship mine across the pond, but note that should you now go to Hinson you would not have to find a donor subframe as he no longer needs a core to modify, and all for no increase in price:2Rolleyes .

[Spartacus]

Hi, just trying to workout the height of the rad and it would be useful to know where the standard undertray is height wise compared with the bottom of the towing eyes as a point of reference.
Could anyone crawl under their fd and let me know?
Cheers.

[mar71n]

From the horizontal face the front anti roll bar clamps to, its 30mm up to the lowest point of the standard air con rad.
So if you clamp a piece of sheet material to the anti roll bar mounting faces & cut it so it fit towards the front of the car. As long as your rad is 30mm above the material face it should be clear of grounding on anything.

[Spartacus]

Thanks for that but atm I don\'t have an arb or subframe to measure from just the towing hooks or the chassis rails.

[Spartacus]

Many thanks, sorted.

[Spartacus]

Not much physical progress to report but a fair bit of research done with regards to the wiring of the LS1 and what wires to match up to from the FD.
As I’ve mentioned before, so far there are a handful of 2004 gto engines running in rx7s in the US but as yet no one has published a walkthrough for the hook-up so I\'m trying to see what has been used on the earlier types of harness and transfer what I can.  

I’ve been buzzing out the LS1 harness and think I now know what needs to be connected, but funny enough the Mazda wiring seems to be the more tricky as the diagrams I have are for the US spec and are quite different, ho hum.

I also separated the gearbox once again because I just wasn’t happy that the bleed for the clutch would be almost impossible to get at once the engine and box are installed. I’ve opted to use a remote bleed line with a speed bleeder on the end. So now I can get at easily bleed the slave cylinder, should I need to.

Oh by the way I weighed the T56 6 speed gearbox while it was off and it came out to 63kg which is 27kg lighter than the Mazda auto box it\'s replacing.:yes

[tinker-27]

hi spartacus,to late now but you can get to the clutch to bleed it ok with a long 12mm socket,but the remote hose is better they bleed real easy and you wont belive how light the clutch is.

[Spartacus]

you wont belive how light the clutch is.

LOL One day I\'d like to find out:rolleyes:

[t2rew]

i did read that the location of the slave cylinder isnt great because with a hard launch the heat in the bell housing causes the fluid to boil.
then you loose the pressure till it cools down. although thats in a heavier car than the rex.

[tinker-27]

never heard of that before most modern cars have the slave round the main shaft these days,ive done loads of very hard launches (mine will launch in 3rd from 10mph with proper tyre smoke!!) and no problems there are six of us round here running ls powered cars nd none have any problems most running std clutches,you can fit a 4mm spacer behind the slave to put the slave into its throw more.

[t2rew]

i read it on a forum so it  MUST be true:)

[Spartacus]

i did read that the location of the slave cylinder isnt great because with a hard launch the heat in the bell housing causes the fluid to boil.
then you loose the pressure till it cools down. although thats in a heavier car than the rex.

I’ve read a few things similar, but I read that the clutch hose from the master cylinder to slave suffers from heat soak. I’ve also read that earlier versions of ls1\'s had an issue where by the same hose had a restrictor in it which had the effect of allowing a quick gear change but only once, if you tried to go for a 2nd quick gear change the fluid didn’t have time to return to the reservoir so you would have trouble disengaging the clutch. Thinking about it they may be one in the same problem as I haven’t seen many recent posts discussing the problem.

[tinker-27]

most modern cars have the restriction in the clutch line m5s,xtypes,rx7s,audi tts, it is very common it means you can get away with a weaker clutch and gearbox, i think the master cylinder being near the exhaust headers is more likely to heat up the fluid that inside the bellhousing. on a fd the clutch and brake fluid is shared so it has a bigger resovior to use,and some people change the brake fluid to keep it fresh but forget the clutch. i have just ordered a dodge viper diff for mine to get better gearing (3.08) this will make 6th a big overdrive but it seems it will pull any gearing.how are you getting on with the wiring ?,they dont make it easy do they ,

[Spartacus]

how are you getting on with the wiring ?,they dont make it easy do they ,

Mmmmmmm now there\'s a question, well the harness came all connected up on the pullout so my theory is I just need to connect the wires that are now on dangling plugs, easy eh? I think I\'m just about there using the pre 2004 harness instructions as a guide but to be honest the hardest part is trying to find the wires suggested on the Mazda harness as 1, the wiring diagram I\'m using is for the US model and 2, some of the wires I\'m meant to be using are found on modules in the car the JDM versions don’t have.

I\'m trying to work out as much as possible before the engine goes in as I wouldn’t like to have to take it out again if I’ve overlooked anything. But saying that the wiring side of things should be ok to mod if I have to once the engine is in (fingers crossed)