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260DET

Richard's 620ZX Coupe

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Some of you would have seen this around, the news is that the VG30DET donk has been removed and will be replaced with a Chev LS 6.0 liter V8 engine powering through a Xtreme light flywheel twin plate clutch and a five speed Tremec with a .82 fifth gear. Engine puts out 430hp out of the box with 480 available from just a cam change. Pics below are of the (white) car as I imported it from Japan a few years ago, the DET engine just before it was removed and the car at Lakeside.

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Edited by 260DET

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Richard - Why the 5 speed and not the 6... weight?

 

Just a couple of comments from my own build:

 

- Think about creating a whole new engine cross-member incorporating engine mounts, even if the mounts are separate. Also, incorporate different steering rack mounts to assist with minimising bumpsteer.

 

- Design your extractors at the same time you are working on the engine mounts, you will probably have to compromise on the optimum design of both to get a working solution. Also, there is bugger-all clearance around the starter motor.

 

- If you are creating new rails incorporate crush sleeves to mount the gearbox cross-member and to add removable cross braces nearer to the diff.

 

- I don't know why I keep harping on about this as no one else seems interested but consider using a GM diff. Mine is the older style out of a VZ but the newer VE diffs are all alloy.

 

Keep us posted on progress.

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Hi Richard

 

Looking forward to seeing the 620ZX progress, I like the V8's  :)

 

someone once said

"There is no replacement for displacement"

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Thanks for the tips Peter, the car is already built, only the engine and transmission is being changed so the rear end will stay the same as the existing R200 is quite capable of handling the power. Why a five speed and not a six is an interesting question, basically with the torque spread of the V8 a six speed would be counter productive for circuit use and of course it is heavier and bulkier too. The lower than usual .82 fifth will be good for the +200kph straights, the high 5th on the Z32 box used behind the VG was painfully slow. Have bought a set of block hugger exhaust manifolds which should fit in the engine bay or at least be easy to mod to do so.

 

VG gave plenty of power but for now I'll just say it was jinxed rather than go into all the detail. Missing Bathurst due to the possibility of engine damage which may have resulted from melted spark plugs was it for me, either call it a day or go V8 were the choices. Turns out the turbo is fine so it's very unlikely that the VG was damaged after all. More pics to come once the stuffed camera is replaced. At the moment I'm waiting on a more suitably shaped GM Performance sump so a trial fit in the engine bay can be done.

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Yeah i didnt have any joy with my VG30DETT although it did do 500rwhp

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Why not put in the supercharged LS3 out of the VF GTS?  Crate engines are only $8000 and you have a very reliable, 550hp with plenty of torque and room for improvement?

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The blokes who race NA LS engines say there is plenty of torque already Roberto, if anything they lack top end power. Plus with much more torque the TKO Tremec would be marginal which would mean a heavier box. Balance is important to me, it makes for a nice car to drive and I must say that my lap times have never been limited by a lack of power.

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Im sure you will love the power of the ls3 I still grin every time I drive mine in its just a ls1 extra .5 litre got be even more fun

 

Mick

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Progress Report. Basically what's happening is I'm doing the work I can do well, the rest is going to be outsourced. Stuff like some electrical, welding, things like that. Where the welding involves fabrication then I'm tacking it first. Engine is located and installed for fitting purposes, the captive mounts are done. The Commodore sump was replaced with a GM Performance item which comes with a windage tray, a crank scraper is on order. The sump will be modified with kick outs on both sides. To improve engine venting for oil drain down purposes a large crankcase vent will be made and fitted. Oil drain down is a problem with these engines for circuit work so the lubrication arrangements are receiving special attention.

 

To bring the engine back close to the firewall the clutch MC had to be removed, it will be replaced with a fabricated internal MC, the gearbox fitted nicely in the tunnel but for the gear lever the opening will have to be moved forward a bit. A suitable and fairly long lever is being made up. With one exception the engine fitted in nicely, plenty of clearance for the steering, the car has a S14 front X member and steering. The exception is the alternator which required the left strut tower to be 'modified', see the pic. Mounting the alternator high and to the left meant that there was more room for the headers which are to be made to suit and the mounts, with the engine so far back the strut towers restrict accessory space. The front of the engine is about 100mm forward of the wheel centers which should help F/R weight distribution.

 

There is plenty of detail work being done but the pictures show the general layout and clearances. More to come, questions and comments welcome.

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No need for Nev to be worried Aub, he has got a real handle on Lakeside now.

 

Thanks Gordon, it should be a blast to drive :)

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Doing the detail stuff at present, like converting from drive by wire to an old school cable operated throttle body which came via Ebay from China. Not a bad piece except that when first fitted it was only getting about 2/3 open throttle. Which is all about the amount of leverage exerted on the butterfly. The lever is an aluminium billet piece so I was able to modify it to reduce leverage which means that for a given amount of cable movement the lever moves more. The actual amount of leverage throughout the movement range can be modified, which gets a bit complex to explain verbally. Cable used is from a FWD Mazda 323/Ford Laser.

 

Had a brainwave, problem was the engine as delivered  had the fuel rail connexions on the left side whereas by necessity the lines from the swirl pot at the back were on the right side. The fuel rail on these engines is a one piece H shaped piece, the injectors are clipped into it so it all comes off together after undoing four bolts. Modern efficient and simple component design, love it. Anyway, the brainwave came when, bingo! it suddenly occurred to me that the whole lot could be rotated 180 degrees and bolted up. Putting the rail connexions on the right side  :D

 

Doing a project like this, love it, built not bought  ;D

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Looking good!!! easier to replace the throttle body than do accelerator pedal mods. The 6.2 will have tons of torque! Are you planning a cam upgrade at this stage?

 

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Someone is on it, yep, cam will add another 50hp to bring RWHP up to about the same as the VG30DET did. Presently just want to get it all sorted and running well, performance upgrades can follow. But really 400+ rwhp will be enough, after that it's driver limited.

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I was just thinking about the throttle body swap. Does the new electronic throttle body have a separate throttle position sensor or is it a part of the motor??

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Luddites ... Mounting the pedal is a piece of cake. Even brake by wire is now the go.

 

O dear, we are fast approaching the age where everything will be connected by wires!

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Luddites ... Mounting the pedal is a piece of cake. Even brake by wire is now the go.

 

I suppose it would eliminate brake fade. And brake bias would be easily adjustable by changing voltages to front and rear callipers.

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O dear, we are fast approaching the age where everything will be connected by wires!

 

Hey dude*, fibre optic cables are replacing wires and cumbersome wiring looms. I can't quite figure this out, I'm the one getting close to 70 yet it appears to me you young fellas are rubbing sticks together to start fires.

 

 

* Not to be confused with the Beatles' song.

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