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Discussion Starter #1
I'm probably really late to the plate with this one, but I have a '70 gt and would really like to strip it down to a sorta road legal track car. Basically just two seats a roll cage some gauges and an engine. At the same time though I would really like to make it haul total butts.. I was thinking about a turbo, but is it realistic to turbo the stock 1.9 and get decent power without blowing it up or is it better to swap another engine in..I am on a budget dropping some high end mostly talked about, rarely seen engine is out of the picture..

Tips and construction criticism is welcome..
 

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Welcome. RallyBob here has a thread on fabricating and installing a high tech turbo install on his GT, best to follow that one. I'm finding that even a veteran Opeler from way back, with superior engineering and fabricating skills like Bob, has had quite the challenge in his turbo install.

PJ Romano has an excellent build up of his 2.5 liter GT engine located in the archives and I do believe your best bet is here, in the 2.4L engine series, where it's superior power over the 1.9/2.0/2.2 engine families makes the lightweight GT "haul butts".:)

But if on a budget, I'd seriously recommend soliciting ideas here about the 2.0 conversion as it's a nice power upgrade from the weak 1.9. Nothing earthshaking, but enough to make the car more sporty to match it's looks. I've driven a 2.0 GT with a combo cam and can tell you it was a nice feel compared to my own 73's low compression chihuahua motor. Good luck.

Mike
 

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Mike's covered the basics and I fully agree with him, but ......

If you want "loads of power" and don't care about "keeping it Opel" or the fact that it will be much more difficult to sell again and all that sort of stuff then I say find a Jap turbo engine and drive train and swap them in

Because

1. It's neither cheap nor easy to get huge amounts of power out of the stock Opel engine

2. The stock tranny doesn't hold up well to abuse

3. The rear axle is kinda weak too and doesn't have an LSD

The GT is an even smaller car than most people realize and this only becomes apparent when they try to swap in other engines, the old Opel engine is actually a very compact engine and pretty much any other engine worth swapping it for will be bigger, which will present some challenges.

There's one member on here, name escapes me at the moment, who runs a Nissan turbo engine in his GT and there are people who've swapped in the 60 degree GM V6's but neither are in the "weld up some motor mounts and drop them in there" category

To quote the punch line from an old joke; "If I was going there I probably wouldn't start from here"
 

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Discussion Starter #4
Alright, thank you guys a lot..I was thinking a cool idea would be to swap in a straight six from a totaled bmw, more power and still german..any thoughts??
 

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Alright, thank you guys a lot..I was thinking a cool idea would be to swap in a straight six from a totaled bmw, more power and still german..any thoughts??
A straight six?

I thought of that once before I got my first GT.

Then I opened the hood and realized that there's no room in the front of the engine to add a couple more cylinders. The body dlopes down too much.
 

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Discussion Starter #6
I mean if I replace the front crossmember the I could drop the engine down a bit..

Or maybe a hayabusa engine..tons of power and very little weight..
 

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Alright, thank you guys a lot..I was thinking a cool idea would be to swap in a straight six from a totaled bmw, more power and still german..any thoughts??
A BMW six would be a tough fit. It's wider, taller, longer, and with the angle of the engine, space is further compromised.

I'm guessing that to turbo your GT engine, presuming it's not in need of a rebuild, it would cost about $4000 or more. That's presuming all new items such as turbo, manifold, exhaust, ECU, fuel rail, injectors, FPR, BOV, high pressure fuel lines, high pressure pump, throttle body, intercooler, intercooler tubing and couplers.

The trickiest part by far is the turbo manifold. But I've found that the lower radiator hose is a tight fit as well.



As others have mentioned, the stock 4-speed and rear axle are questionable after 150 hp, and destined for a very short life after 200 hp. A much stronger clutch is a necessity.
 

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That's an interesting idea..I'll have to see what's what at my local junk yard..

It seem that Rallybob is basically saying g not to turbo the stock 1.9 by the end it doesn't seem worth it..

I was looking online and can easily get a hayabusa engine for around 1400 bucks which is totally reasonable..my only concern is yes it is light and yes it has a lot of horsepower but the torque is extremely low for the hoursepower..won't this affect the acceleration??
 

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It seem that Rallybob is basically saying not to turbo the stock 1.9 by the end it doesn't seem worth it..
Wheel I thing hes saying that the stock engine will handle boost.
Forged crank,rods..forged pistons.
The rod bolts wheel needs to be new ones.
The cylinder head bolts are up to the task as is the headgasket.
The driveline...wheelllll
 

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Wheel I thing hes saying that the stock engine will handle boost.
Forged crank,rods..forged pistons.
The rod bolts wheel needs to be new ones.
The cylinder head bolts are up to the task as is the headgasket.
The driveline...wheelllll
Rod bolts?

You do know they don't have much to do with the compression stroke, right? They take the most stress on the intake stroke. With a turbo, this stress is reduced.
 

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Discussion Starter #13
Mm yeah, it is said that the best engines to handle boost are factory cast iron or aluminum..but if what Rallybob is saying and it will take about 4 grand to turbo my stock 1.9, I can get an already turbo'd engine for about half the price..

Does anyone have any insight on the whole high HP low weight hayabusa idea..with the low torque be a substantial issue??
 

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.....with the low torque be a substantial issue??
A friend of mine raced a go-kart with a turbo.
He had to jump up and down in the drivers seat to get the tires to slip
there by getting the engine into it's H/P curve.

Once in it's power band it was rocket fast>>>>>>>>>>>
Passed most competitors before the last few feet of the finish line.
 

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Alright..just have to figure the power band..

What is the bare minimum things I would need to turbo the stock??
You'll need an EFI system. You can use the 1975 Opel intake manifold (or later Euro 2.0 I take manifold), but little else can be reused. So a throttle body with TPS, a custom fuel rail, pressure regulator, injectors, hard fuel lines, high pressure pump. If you are good at fabricating and dumpster diving, you can do the basic EFI stuff for $300-$500.

However, you need a tuneable ECU. The stock Opel system is analog and not tuneable, so you need an aftermarket ECU. Megasquirt can be had for as little as a few hundred dollars if you assemble it yourself.

On top of this, you'll need a turbo manifold (tight fitment), turbocharger (limited space in a stock body, so we're talking a small framed T25), 2.5" exhaust preferably, intercooler, intercooler tubes and couplers, and improved cooling. I'm glossing over the details, but some of the work is very detail oriented due to the tight confines of the GT underhood.
 

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That's an interesting idea..I'll have to see what's what at my local junk yard..

It seem that Rallybob is basically saying g not to turbo the stock 1.9 by the end it doesn't seem worth it..

I was looking online and can easily get a hayabusa engine for around 1400 bucks which is totally reasonable..my only concern is yes it is light and yes it has a lot of horsepower but the torque is extremely low for the hoursepower..won't this affect the acceleration??
What would a turbo on a stock 1.9 dyno?:confused:
 
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