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Engine Conversion Question


screwball
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Hey Ladies and Gents (mostly Gents),

I was hanging out with some mates the other night when we saw a very sexual R32 pass by that sounded somewhat more impressive than the usual.

I was told by someone "in the know" that the car had been upgraded to an S15 SR20DET engine from the standard R32 RB20DET engine.

Questions:

- Is this actually doable?

- Does the SR drop straight in or are there hardcore modifications to do?

- Can you buy SR engines by themselves? If so, where from (if known)?

- Would the R32 drivetrain withstand an SR upgrade (being that I understand the SR to be more powerful)?

- Am I massively ill-informed?

- If this is not do-able, what would be the cheapest/most cost effective engine upgrade?

I am soon to be owning one of these fine machines (R32 GTS-t) and I would seriously consider financing the upgrade if it's possible and feasable to be done.

Any answers would be greatly appreciated.

Adam

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Its been done heaps before mate.

There is a bit of mucking around to get it right... You would be better off dropping a RB25DET into the R32 and be done with it..

The standard r32 drive train would be fine except for the manual gearbox's are allways the weak point in a R32.

Go the rb25det much better conversion IMO

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the sr20 conversion is good. it makes the car handle better, and more nimble. becase the sr sits with most of its weight in the rear of the engine bay.

more info can be found in the latest 'zoom' magazine

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Its definitely do-able...but i see one problem with your first post...a sr20det sounds more impressive than a rb20det? seems to me that theres something not quite right there...

Edited by limpus
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Yeh, i agree on that, rb20 sound is far nicer than the sr20 sound

You also have to consider which model sr20 you want because there are different models from different years. It's a same-sized engine and if it's the same year as an rb20 i'd be expecting it to put out less power not more :(. The new ones are nice though if that's what your looking at, people mod the crap out of them and they handle it well, but then why upgrade to a silvia engine when u can drop a rb25 in the same space as your old rb20 fit, easily, and have an extra half a litre of displacement + shedloads of torque

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Yeh, i agree on that, rb20 sound is far nicer than the sr20 sound

You also have to consider which model sr20 you want because there are different models from different years. It's a same-sized engine and if it's the same year as an rb20 i'd be expecting it to put out less power not more :(. The new ones are nice though if that's what your looking at, people mod the crap out of them and they handle it well, but then why upgrade to a silvia engine when u can drop a rb25 in the same space as your old rb20 fit, easily, and have an extra half a litre of displacement + shedloads of torque

I'm not really a fan of an SR but i have to admit that they do produce the numbers too...they also do have more torque than the rb20...

Screwball...the question is...why do u want to change it to an SR? is it because it sounds "better"? because thats probably wrong...if its because u want to improve the handling and weight distribution...perhaps...if you want to be different...don't bother because its been done several times...and if its just because u want an SR...then don't destroy a perfectly good 32 and buy a silvia instead...

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it is doeable without to much hassle actually. it is a common sidegrade with cefiro owners who want to drift.

I have driven 2 cefiros with SR20s and about 4 with rb20's and the sr is better for drift and low down torque.

talk to "to much boost" on the silviansw forums, he is a knowlagable bloke who has don the conversion hiself. he would be able to give you an exact rundown on what is needed and the cost. his is a very tidy job and performed very well

Cheers

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The reason I've looked into it is because I did like the sound of the engine but on top of that I've been told the RB's of that era tend to fail a bit, on top of that I would like a newer age SR (from say an S15 Silvia) which puts out better power figures but also is going to be better on fuel (a moot point in the quest for power obviously but still say-able :() and more resilient, I'm told.

I figure an engine made in 1999 or whatever will be much more reliable and economic than one made in 1990.

How much would someone like me expect to pay for an SR20DET from an early model S15 with reasonable k's? How does this compare with the cost of a low k's RB25DET?

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it is doeable without to much hassle actually. it is a common sidegrade with cefiro owners who want to drift.

I have driven 2 cefiros with SR20s and about 4 with rb20's and the sr is better for drift and low down torque.

talk to "to much boost" on the silviansw forums, he is a knowlagable bloke who has don the conversion hiself. he would be able to give you an exact rundown on what is needed and the cost. his is a very tidy job and performed very well

Cheers

I helped with the above and did most of the wiring work on it. Very straight forward conversion.

In a nut shell, you will need the engine, loom, gearbox and engine cross member so you may as well buy a half cut. You are better off with an s14 engine which is pretty much identical to s15 as it has the stronger box and will fit up with the stock manual r32 tailshaft.

On the cef i think we used an s15 rack and cross member as he had one in good condition but the tie rods had to be swapped for s13 items to get enough adjustment to straighten up the wheels. Minor mods to the gear box crossmember (elongated holes) and a bit of minor chopping of the hole in the floor for the gear stick as it sat further back i think.

Clutch master had to be swapped for an s14 item to clear the back of the sr plenum and hicas was removed completely as he used the sr power steering pump/rack which didn't have provision for the hicas and it was already locked anyway.

I was considering this swap into my r32 but figured the extra .5L out of an rb25 was a better idea. It was.

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I'm just suprised that you were impressed by the sound and thats what made you think something different was going on. striaght six always sounds better than a 4 cyl imo. But yeh has been done. i'd go the rb25 route.

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Ok so what is needed for an RB20 to RB25 conversion? Do I need an R33 gearbox too or will it all hook up?

I'm only planning to do ECU remap, FMIC and zorst to start with, so will I need upgraded box from the word go?

Thanks for the help guys.

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i think the s15 sr is quite dear in price..the rb25 would the best option plus cheaper as the front cut would be as dear plus ya get even better box again..

rb sound way better than sr 4 bangers

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The 25 will fit up to the 20 box. You just need an engine, loom and ecu. You use the 20 engine mounts, AC compressor and power steering pump. The rest just fits up to your existing dump pipe, intake pipes and the like.

The 20 box is under rated. Mine is still happy at 288rwkw, though i'm swapping to a 25 box now as it's only a matter of time before it dies.

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