My new engine 280+HP engine ...

I've had a great day today. It's sure great being a single guy sometimes, as how many girlfriends would let you build an engine in the loungroom in front of the TV like I've started doing today. They surely wouldn't have let me spend this much on an engine! 😀

Well here it is, my new turbo engine. Still working out what I'm going to do for heads, but thus far the only factory parts are the gasket kit, cam drive gear, woodruf keys and gear retaining clip. Thats about as stock as it gets.

All engine parts are imported. The crankcase is a welded machined and fully worked over Rimco case, crank is a CB 4340 nitrided 84mm stroker with chevy big ends, rods are 5.6" h beam 4340's, cam is a engal turbo grind TCS-10, cb strait cut timing gears, and a dry sump oil system.

I'm wanting some reliability and drivability with this new turbo engine, so i'm planning on keeping the boost to a sane 7lb for street use, but when wound up to say 15lb it should be able to produce in excess of 280hp.

Should do easy 11's I think, and eat STI's for breakfast.

I'm fitting cylinders tomorrow to measure up what spacers and head gaskets I need to run a 7.2:1 compression.

Here's some pictures.

[Edited on 29-5-2004 by iswinkels]

Amazing how beautiful a few pieces of metal can be!
So jealous!
Dan🙂

that's gonna be one awesome motor!!!

i know what you mean with the single guy thing too, i'd never get away with spending all my $ on my car if i had a missus!!!

kai

iswinkels wrote:crank is a CB 4340 nitrided 84mm stroker with chevy big ends, rods are 5.6" h beam 4340's,

Do you know how much wider than std it'll end up being with that combo?

My 1971 toyota two door with a $380.00 MR2 turbo motor runs 11.5 seconds :alien

Not a whole lot of width wider i'm guessing

I'll probably end up with a 0.060" or 0.090" head gasket, and the spacers will probably be arount 0.090" too. Just guessing of course, as this is the first stroker i've built.

Pistons are 94mm mahle B forgies, which are designed for strokers (wrist pin is closer to the top and rings).

The heads i'll be running are either 56cc's or 57cc's I think, depending on whether I go with the CNC round port cb head, their street eliminator head, or a mofco 050 cnc head. Still undecided ...

I guess i'll find out how much wider exactly tomorrow when the pistons go on for a trial fit up. It won't be a problem fitting it in the engine bay tho, because if it measures too wide, i'll just have the body modified a little. Its at the panel shop at the momemnt receiving the full bare metal respray treatment.

Here's a pic of that too...

Cheers,

Ian.

Cool

The MoFoCo heads don't have a real good reputation from what I've read on the forums. Just thought you should know so you can make an informed decision.

what brakes are you going to use to pull this up ?

Porsche 305mm 944 turbo ventilated brakes, 4 piston calipers.

I haven't done the rear end yet (currently type3), but that will me 944 turbo also. I've been too busy with other projects....

And here's a picture!

Yes... interesting how a few bits of metal can be so loverly! Those 944 Turbo calipers look a treat! Keep up the great work dude!

btw, whats the advantage of having straight cut cam gears?

Cheers
C

oval TOFU wrote:btw, whats the advantage of having straight cut cam gears?

Cheers
C

to the best of my knowledge it's cos they have less friction, therefore basically freeing up some of the engines power..... they're pretty noisy tho (in a good way i reckon...)

kai

yes that is correct 1 to 2 hp less oil lag .my mild motor I cut a grove on the lathe in the gears works a treat .

gears get whiney like big block race cars ey?

nice one!

Straight cut gearing eliminates all load on the cam thrust bearings, and yes they are less friction also.

Eliminating thrust is a comfort to me knowing that there won't be any end float of the cam. I've had to clearence the cam next to the center bearing to clear the #3 rod on the down stroke. There isn't a lot of clearence between the rods and the cam with an 84mm crank.

I can't hear the straght cut gearing of my current engine over the noise of the 911 11 blade fan, not to mention the 2 1/2" exhaust, or the turbo spooling up.

Ever wondered why air cooled porsches sound like they do? Well it's mostly fan noise. Not that I mind my VW sound like a porsche on steroids!

Cheers,

I konw that straight cut gears a weaker than helical-cut gears as only 2 teeth are handling the load... this wouldnt be a concern I presume?

Choppa has a turbo set up in Perth for sale ,as well as some big new pots ect to clear .he has the subaru turbo in there

just went to ya website... your car sounds amazing!

Yes straight cut gearig would be weaker if it were an aluminium on steel straight cut setup, but the gearing material is forged 8640 chromoly steel, which is the same type of steel used with gearing in transmissions. Pretty strong stuff.

Thanks for the feedback about the website too. I'm actually updating it now with some info about how the garrett GT25-320HP turbo upgrade performs.

I'm running 15lb boost now with a turbosmart gated controller to bring boost on faster.

I've also added an air bleed valve recently to allow computer controlled idle speed, all in the name of making the car a little more friendly to drive. It works realy well too, regardless of engine tempreture.



[Edited on 29-5-2004 by iswinkels]

Hi Ian,

I've got the same rods in 5.5 inch, they really are a work of art, it's a shame they are hidden away in the case. Any particular reason u chose 5.6 inch?

As for the barrel spacers, u need a 9mm spacer for an 84mm crank with 5.7 inch rods with 'B' pistons, of course every engine will be different but this will give an idea what u are looking at . Have u seen the new 'C' pistons with an even shorter crown to gungeon pin height.?

In regards to hp, the last time we went to the dyno, Leighs 2007cc turbo got 155hp @ the wheels at around 5000rpm with only 13psi boost, should have been running 15psi. He has since fixed the boost & ran a 12.9 quarter in a 900kg street car. We'll be going back to the dyno soon so it should make a bit more with the boost sorted.

regards
Jak

Out of interest, what sort of side clearance did you end up with, with between the rods, crank ? I only ask because I found them (CB) to be a bit on the loose side (.018 - .020" )

Straight cuts only whine if they are tight on the backlash (friction ???) mine make no noise at all...

With the low compression I would guess it will be 20mm or so wider overall, could be fun getting everything to fit !!!

Gonna be an awesome ride though !!!

[Edited on 29-5-2004 by AdrianH]

Adrian, my rod side clearences averaged 0.020" also, which is within spec but closer to the loose end of the scale. Factory clearence is 0.06"-0.028".

I figure the bigger gap could be intentional as the crankshaft and rods are made of a diferent material than the factory crank and rods. I'm no metallurgist though. My rod bearing clearences were all 0.038mm, factory being 0.016mm - 0.102mm, so I was quite happy with that.

Jak, does Leigh have a webpage that I might read about his ride? The HP figure doesn't seem right because my 1641 turbo engine is making about 160 at the wheels with 15lb boost at about 5500 rpm.

I had a lot of issues getting that figure though. Exhaust gasket leaks, leaking header welding, and intake system leaks from bad gaskets that only leak when under pressure are a pain to fix. Thanks to that copepr based high temp silicon and a full set of new intake gaskets and seals it's all under control now.

Is he running carbs or an EFI computer? Is it intercooled or or water injected?

Cheers,

wow! this is interesting stuff. awesome job on the car ian.

Youll get different stories form different people, bentley says .04 - .16" end play (side clearance) in a stocker. Wider clearance helps get rid of hot oil, as long as you have the volume to keep up with the evacuation !!! Dont wanna starve those bearings...

Well I have measured up the deck heights for each cylinder, and it appears the engine will be about 9.5mm wider than stock over all. It requires 6.5mm of spacers to achieve a 0 deck height.

I'll be using a 0.395" (10mm) spacer on each barrel with an additional 0.010" shim, which gives me a 0.147" deck height. With the 0.060 copper head gasket, i'll have my 7.23:1 compression.

For those that build their own engines, have a look at this excel spreadsheet. It's great for calculating compression ratio's and engine geometry.

About the oil system... I'm using a dry sump pump, and have an electric oil pump to circulate oil from the tank through the remote cooler. The electric pump is controlled by the efi computer.

I've been looking at turbo charging for a while now, and the biggest prob is room, what turbo are you looking at running and what type of cooling have you thought of, other than that it sounds like a great combo good luck and keep us informed.

Cheers

Have a look at my website. I've just finished uploading the new content with the stage 3 turbo upgrade. The turbo i'm currently running, and will be using on this new engine is a garrett gt25-320HP turbo. On a 2380 it will be a little on the small side, but I'm not chasing all out HP.

On this engine the GT25 will be lag free, and will basicly drive like i've got 4.5 litres of engine capacity.

Cooling on the current engine is a home made porsche style system with a remote oil cooler. The new cooling system is a sharpbuilt carbon fiber shroud. I have a lot of custom work to do though to fill in the gaps around the turbo, and pully etc.

I'm taking the car off the road for a month to do the fit out, just so I can make it all perfect.

http://www.clubvw.org.au/leigh_harris.htm

Heres a link to Leighs car. It will rexplain everything in heaps of detail.

regards
Jak

So you are running a mechanical pump on the case out to the tank ? and an electric pump from the tank to the cooler to the case??? What is the pump volume based on ? RPM only ??

Its all getting to tricky for me !!! How long have you been planning the engine, and overall combo ??

[Edited on 30-5-2004 by AdrianH]

What I was asking was what type of turbo cooling ie. intercooloer or not, air to air etc...

fark this should be awesome 🙂

Hows the tranny gonna handle all this power?


[Edited on 30-5-2004 by Che Castro]

Lots of new questions to answer...

Ok, the oil pump for lubrication and scavenging the sump is purely mechanical, so volume is rpm based. The oil tank is located inside the car behind the back seat (under the speaker tray). The cooler is located underneith the tank, to the right of the gearbox.

I've been collecting parts for this engine for about 3 years now. My 1641cc turbo engine has allowed me to try diferent things and to work out where I can make improvements, as well as learn a lot of things.

Turbo aftercooling, my current plan is to use two small water to air intercoolers (one each side of the engine), and a radiator under the rear left guard. There will also be a ERL 2 stage water injection kit that will be controlled by the EFI system.

As for the transaxel, there are two ways I might go. One is to rebuild my current transmission into a rhino case and add a superdiff and big side plates, or alternatively import a completely worked over transaxel from rancho. My rear tyres are 205's too, so I expect to brake traction before breaking the gearbox.

A friend of mine here in cairns is importing rancho transmissions and scat engines for use in VW powered trike's, which are then assembled here in australia. I'm hoping to place an order with their gear.

Definantly staying with swing axel though. I'm not into going around corners too fast, and much more prefer straight lines. 🙂

[Edited on 30-5-2004 by iswinkels]

And evan more questions,

Where are you locating the turbine itself

Are you using 95mm p and c's ??? Thought I read 2380 somewhere ??

there was a post on the web regarding lag .To stop this there was a regulator fitted from Metal work * I find the post and let you now .I sell the reg fitting ect and valves in perth * just to let you know * :rudolf

Jak Rizzo wrote:In regards to hp, the last time we went to the dyno, Leighs 2007cc turbo got 155hp @ the wheels at around 5000rpm with only 13psi boost, should have been running 15psi. He has since fixed the boost & ran a 12.9 quarter in a 900kg street car.

Hi

Shame your so far away I would love to have a look at your car and have a good chin wag. Leighs time was done during bracket racing, so he was backing off and taking some boost out so that he didnt break out.

I've also gone the Porsche brake route, if you have any questions or problems drop me a line. http://www.clubvw.org.au/steve.htm

1302Steve

Lowbug, Well the turbo is located under the rear apron (based on a CB hideaway header, but chopped up and modified a little).

Adrian, yes it is a 2380cc engine.

Seagull, I don't get how fitting some kind of regulator is going to reduce lag? Fact is we are talking about allowing the turbine to spool quickly at low rpm, short of having a smaller exhaust ar turbine, or a VNT turbine (ideal) there is little can be done.

The only bolt on that *realy* helps eliminate lag is nitrous, which would be over kill for the engine i'm building...

1302Steve, I agree. I've read a lot about your car on your website and the germanlook.com forum. I agree it would be great to be able to compare notes and experiences. If you are on MSN at all feel free to contact me for a chat, or email me directly. I'm online most evenings. Thus far I've made contact with only one other guy (in the US) that has a turbo bug that I've been able to share notes with. Fortunanty he has the same engine management system too, so we have been able to share ECU maps too.

Cheers,

What an awesome build-up!! I love seeing current technology in use on 60-year-old engine designs! :thumb

Me Too! With the exception of the lowered stance, porsche wheels and 2 1/2" exhaust it looks stock from the outside.

The new body is being painted pure white, so it will look even more like a sleeper... little will the unsuspecting wrx sti/skyline gtr know... 😀

Man.... I'm totally awe struck, awesome dude, awesome!

I'm interested in the comp ratio calc but the formulaes didn't work with the attachment. Is the original available on the net at all.

BTW hats of to what your doing will be eagerly watching

yeah, wrx sti, skyline, porsche, lamborghini diablo etc etc.

What a rocket !

Keep the updates coming please, its fantastic reading.

Absolutely. This is an excellent post. It explains everythign really well too and there isn't anyone 'knocking' other peoples ideas and stuff. Fan-bloody-tastic. Subsequently I have started reading up about EFI and turbos and it is a fascinating subject. All the power dude; literally!

Here's another copy of the deck height calculator spreadsheet. I fixed the bugs with the formulaes on cylinders #3 and #4, and unprotected the document so you can make modifications easily now. Hopefully they were the errors that you meant.

I don't remember where I originally got the spreadsheet from, but it's an excelent little tool.

As for the remaining parts for the engine, it looks like i'll be going with a pair of CB street eliminator 2000 heads with a mild port, custom length aluminium pushrods from aircooled.net and empi or pauter 1.25:1 roller rockers.

I've ordered my spacers and shims so I can do a final measure up with everything bolted firmly in place. After that I'll be ordering the heads and remaining parts.

It will probably be about 6-8 weeks till everything arrives and is machined and ready for the next phase of assembly, that being to a rocker cover to rocker cover stage.

The panel shop has most of my "new" '66 shell in final primer now. Chrome strip holes, a few rust spots, bumper overriders, exhaust cutouts, and previous bad panel work have been fixed/welded. It's looking pretty sweet!

I'm going to try and get some more pictures this week. If the weather holds out, it might be ready for the spray booth mid next week, which means my weekends are about to get very busy with the complete re-fit and rewire of the car.

Has anyone ever tried sourcing an aftermarket power window lift kit before? I'm thinking of converting the single piece glasst to use an electric lift system and have no idea where to start looking in australia...

Thanks for the feedback to everyone! It's good fun being able to share my obsession with other vw freaks!

Cheers, :beer

Hmmm, there are a few kits around.... my local Tandy bloke (whom I get my Jaycar stuff from) stocks electric window kits, but I couldn't tell you the brand.

Some kits obviously won't suit the space you have available. I've been wondering whether it would be practical to use the kombi window actuator system (cable driven) so that it is possible to mount an electric conversion virtually anywhere in the door..... this may work on a Beetle too....

Damm , I've drooled over my key board.
That is one super Tough combo, how light can u make the car?
Should be able to get even lower ets with set up and light weight.

Very impressive indeed! Do you expect any problems with compliance for your new engine with QLD certification requirements? Any forseable probs with the oil tank inside the cabin (behind rear seat)?

Looking and sounding great!
Alan

I've got the plates on the car for all the existing mods to date, but I didn't think about the oil tank requiring approval. It will be concealed under the speaker tray, so I figure what they don't see won't hurt them.

As for the weight factor, it will weigh in close to about 780-800kg. That give a power rate ratio of 3.75kg:1kw, which is better than a porsche GT2.

I've changed my mind on the cylinder heads again... going for CB CNC 044 round ports in favour of getting better cooling from the more surface area of the heads (instead of the SE2000 heads).

I'm going to check out the new '66 shell this morning. It's getting its final spray this next week! Body/chassis swap happening next weekend (lots of work).

Ian when I hit Cairns later this year I am definitetly looking you up for a photo session (test ride?) hubba hubba 😉

if you dont mind me asking. what was the total cost of this conversion. (engine only). not brakes or anything.

thanks

anthony

Truthfully I don't know exactly what it cost... Real enthuesiests don't keep recepts 🙂

At a ballpark guess though I'd have to say this would be an approximate breakdown...

Bare engine to long block - $4500
Oil cooling and fittings and oil lines $500
Porsche cooling system - $1000 (Home made shroud, materiels inc)
EFI ECU, plumbing, tank mods, fuel lines - $1800
Exhaust system + header - $1500 (including all modifications i've done so far)
Garrett GT25-320 Turbo - $1600
MSD, Coil and Ignition parts - $1500 (including recent conversion to distributor trigger, allowing full sequential injection)

That would be about it I think. As you can see most of it isn't the actual engine, its all the other parts needed to support it etc.

The 2380's still on hold for the moment... The new bare shell will be finished inside of 2.5 weeks now, in Porsche Arctic Silver, instead of white. Saw the body last weekend and it is perfectly straight.. I'll post some new pics later.

Oh, and yesterday I was interviewed by ABC radio about my car. They had me do a walk around and talk about the things that have been done to it. Then had me start the car and rev it a few times. I gunned it twice, first to 4500, then to about 6000. I nearly frightened the reporter out of her skin!

They played it on the radio this morning at about 8:30. I'm getting a cd copy of the broadcast later too, so i'll make it available for download from my website.

Cheers,

[Edited on 23-6-2004 by iswinkels]

Ask Wes about the electric windows, he has them in his Baja and has fitted them to another Guys Beetle as well.

What pistons and cylinders are you using ???

I've put the power window kit on hold for a little while. I've got enough going on without taking on yet another major modification. Ive started making up new looms for the new shell when it comes back from the panel beaters.

AdrianH, both my engine used mahle forgies, the 1641's using 87 and the 2380 is using 94's. Both have mahle top and oil rings, with total seal second rings. As i'm not going to push the power output into the 300+ mark (with the 2380) i don't think I need to go to wisco cnc forgies, (though the endless possabilities with gudgen pin heights were tempting).

The latest pics of the body. At this stage its at about the 3rd coat of high fill primer. The panel beater tells me the body work is that flat, that i could get away with painting it black, so i've changed the colour to arctic silver instead of white.

It would be a shame to paint in a plain colour when so much effort has gone into making the lines and panels perfect.

Here's the pics...

Another picture.

Another picture.

[Edited on 23-6-2004 by iswinkels]

i dunno about silver meself.....
ive seen bugs in silver, the shapes not right for them...
but maybe it was just a bad one...

I think silver can look shit hot!

Hi

I reckon CTs silver is very nice, some silvers just dont photograph very well, they look like grey primer.

1302Steve

HI,

Good decision on the heads.

Mofocco are terrible and do not last.
Street eliminators..both bugpac and cb run 50 deg hotter than 044's or standard casting on a normally aspirated engine let alone a turbo. They are good for short trips and ocassional drives.

With the turbo you do not require big valves at all...simply a port job to minimise restriction, especially with a small turbo.

Even the quickest street cars like Scott Bakken and Lee Gong in the states both have 2332 normally aspirated 11 second bugs, 200+hp and only 42x37.5 heads...Bigger is not always better. I bought some 46x37.5 heads with all the bells and whistles and have decided they will be a negative over the smaller valves..waste of money, by rushing in...silly.

Good luck, look foward to more updates.
Matt

Well the porsche arctic silver is about the same as the silver ragtop that is show above. My new car isn't a ragtop, but it does have all the bells and whistles.

I've been collecting all those nic-nac and accessories that "finish" the appearance of the car for years. Aluminium billet bumpers, billet running boards, stainless anti-scratch plates (under the door and hood handles), 911 headlights etc.

Wheels are porsche 911, 964 cup 1 17x7 and 17x7.5, with 205x50 and 215x50 rubber. These are a straight spoke wheel.

I can't wait to get the body back from the panel beaters... Only about 2 weeks to go now.

Cheers,

[Edited on 27-6-2004 by iswinkels]

MR iswinkels can you please tell 71 super how many of these $ the motor cost ,he is trying to do the same ,thanks seagull

Thats a tough question to answer. I don't consider myself an expert on this subject but I can offer my opinion and some advise tho.

It all depends on what your trying to acomplish... becuase the moment you go down the turbo vw engine road your generally looking at least $4000+ (thats not including the engine). There are so many things to consider...

Exhaust system changes
Beefed up oil system
Carb or injection
Engine management systems
Cooling
intercooling
Engineering approval (if you want a turbo street car)

A 2380 turbo engine in any form is going to produce some impressive TORQUE and HP figures but it all depends on your application. Building the low end turbo 2380 is going to whip the ass of nearly all engines over the quarter, so when I say low end I'm referring to the $$$ factor and not the FUN factor. Turboing an engine is all about getting more torque so you can go faster quicker. Turbo engines produce much more torque than a Naturally aspirated engine at the same power range. This allows you to have much less RPM's and still be keeping pace with a NA engine thats turing through 7500 RPM.

You could build a low end 2380 "fairly cheaply", run a stock cam, and smallish (Nissan T28-SR20 $350.00) turbo (7lb boost) and still have 220-240hp and good reliability! The dollar factor would be quite reasonable, say a guess around the $5-6K head to head. (no cooling, exhaust, or induction system). Modified crankcase, welded 84mm stroker crank, Hbeam 5.394" rods, and a pair of unported cb 044's for some top end strength. This sort of engine would be driven mostly under 5000 RPM, have fantastic torque in any gear and be economical to run.

Then there is the engine i'm building, more or less middle of the range power output for a turbo 2380. Main diferences are 4340 forged bottom end, 5.6" rods, wedgemated crank, barel spacers required, turbo grind cam and ported heads. Hopefully around the 300hp mark at 14lb, which is also the upper limit of the 8mm head studs. You would use a T3 from a skyline RB25, or go for a modern GT25-320 class turbo as I have, not so much for the performance but you need to be able to keep the airflow up to the engine. Costing around $7000 head to head. I'm also running a dry sump oil system for something diferent, and a little more ground clearence.

A 2380 can be taken a lot further up the power output scale but requires major changes. (Flanged crank, aftermarket cylinders and pistons as Mahle won't be strong enough, bigger cam, bigger heads, aftermarket crankcase(autocraft/scat), 10mm headstuds, porting etc). With 20lb boost this engine would make 300hp easy, and at higher (say 30lb) you'd be making maybe 380-400hp. If you on this path you'd be running a GT30-450 turbo BIG $$$$. Cost estimate would be 15-18$K+, as all parts are aftermarket, AND require custom modification in some way or another. Only die hard vw fans would do this, because basically your better off buying a porsche flat 6 and running a low boost turbo setup (if you want air cooled), or go for an EJ20T for some modern reliability.

Well thats just my opinion. Feel free to throw in some other ideas...

Cheers,

[Edited on 8-7-2004 by iswinkels]

This is a good site in regard to what to expect with a turbo

http://www.turbobobefi.com/

What cam are you using ??

I'm using an engal TCS-10 with 1.25:1 rocker gear, which makes for 284 intake 276 exhaust, 0.530" lift at the valve.

It should come hit full boost around 2500 RPM and hold 12lb till 6500 RPM. The low end torque will be very impressive, traction being a problem... 🙂

I'm ordering my heads and the last parts to complete the engine next month. The shell swap happens in 9 days..... and counting....

Cheers,

Thanks for your post on costs Ian , gives the gang a idea of what things cost , ta seagull

thanks "ian" but i was not looking for a stroked turbo'd engine. lol. it was to be a turbo 1600 or a 2275. not a turbo'd 2275. lol. i was finding which would be the cheaper option of those 2. sorry if you mis understood.

i will eventually build a 2380 turbo or something along the lines. but that would be once i alreay have a motor in my car that can satisfy me and be not as expensive. i am not looking at the 220+hp vw engine at the moment. so turbo 1600 or 2275?

Hey Ian,
Agree with everyone here - your project is awesome!

The CB 044 CNC ported heads you are thinking of ordering are'nt all that one would expect. I have physically handled a set and they needed alot of further work to get them close to being 'ported'. In fact at the time I was able to run my fingers inside the ports of a stock VW casting at the same time - the VW casting felt alot better in terms of its port shape and finish - without any porting whatsoever!
Call AJ Sims in the US (www.lowbugget.com) and have a chat to him. He ports CB 044's all day long for all types of applications (incl turbo). Ask him about the CB's CNC ported heads. He is a 'straightshooter' and won't BS you regardless of where/ what type of heads you decide to get. He will explain to you why the CNC ported heads just don't 'cut-it'.

Good luck with the rest of your project. You are an inspiration to the rest of us!

Cheers,
Ali 🙂

[Edited on 10-7-2004 by primate]

[Edited on 10-7-2004 by primate]

seems like a shame not to with all that power. How did the car behave with the old engine? Coz by the looks of things it will be that to the power of 10.

😠

There's two ways I can go with the transmission.

1. Import a custom made rancho transaxel. I have "contacts" and can import at a good price. The axel will cost about $1500-$2500 but will have all the trimmings and be built for 300hp+. Rhino case, straight cut, forged, welded etc. Quaife LSD diff if I can get it, otherwise just a superdiff. And bigger axels too.

2. porsche 901 5 speed conversion, irs conversion, porsche 930 cv's. Gives me an LSD and 5 gears, but to be 100% happy with this conversion I'd have to have the ratio's changed, and that means big $$$$.

I'll probably go for the rancho option, simpler, more original, less work. Fact is my car is built for straight lines, and not corners, so the IRS would never realy be used to its fullest potential.

Cheers,

What is the difference between the gt25 and the gt28 and how are reated and how did you go about selecting the write turbo?

Thats a question that can't be answered very easily. Basically the GT25 and GT28 are the same turbo with diferent housings.

The exhaust housing changes the RPM at which it will start spooling at, and the compressor housing more or less determines the air flow of the pump... well sort of.. In reality its a lot more complicated than that, because the exhaust and compressor housing combination together determinel the overall responsiveness of the turbo.

As for selecting the right one.. Go to big and you've got lag and a turbo that is only just starting to spin before your changing gears, and too small and you've got excelent low end responsiveness, and no top end because you run out of air flow.

It's gotten a lot easier now tho. The gt series turbo's ratings more or less reflect the amount of air they can flow to produce x amount of HP. For example, the GT25-320 will produce from 280-320 before it enters the surge "danger" zone and heads torwards self destruction.

Have a look at http://www.turbofast.com.au/GTseries.html .