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Rb25det To De Compression

kyriako

By kyriako,
in Engines & Forced Induction

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StealthX Veteran

StealthX

Posted
Posted

lol another one of these threads...

Raising the compression ratio means a complete rebuild.

i.e. taller pistons.

would cost upwards of 4k for such a job.

Why is it always R33s that noobs ask these questions about?

Nigel Nichols Explorer

Nigel Nichols

Posted
Posted
lol another one of these threads...

Raising the compression ratio means a complete rebuild.

i.e. taller pistons.

would cost upwards of 4k for such a job.

Why is it always R33s that noobs ask these questions about?

I think you will find that if you used the pistons out of the RB25DE it will raise the compression. My understanding is the DE pistons have a large dome than the DET's but do some research to confirm.

I used the RB25DE pistions in my RB30DE rather than the 30 pistons to gain higher compression.

Here in NZ we are not effected by such things as removing a turbo since it is reducing the engine output. I don't understand why the aussie authorities have an issue with reducing engine output.

Nigel

mad082 Grand Master

mad082

Posted
Posted
I think you will find that if you used the pistons out of the RB25DE it will raise the compression. My understanding is the DE pistons have a large dome than the DET's but do some research to confirm.

I used the RB25DE pistions in my RB30DE rather than the 30 pistons to gain higher compression.

Here in NZ we are not effected by such things as removing a turbo since it is reducing the engine output. I don't understand why the aussie authorities have an issue with reducing engine output.

Nigel

that is sort of beside the point. why bother spending all that money buying a turbo car which you know you can't legally drive, then spend another buttload of money making it legal, which you will then have to spend again making it turbo again? why not just buy a natro to start with, then sell it and buy a turbo one when you are legally allowed to drive one. will save quite a few thousand dollars in the process.

N-DAWG Mentor

N-DAWG

Posted
Posted

You're "altering the performance of a vehicle" by performing an "engine modification". That and the vehicle is still a GTS"t".

In short, it's not going to be legal, at least not without spending a lot of money. Also good luck convincing a Police Officer that your GTSt is non-turbo when, and I do generalise here, a lot of them don't know what they're looking for and in some cases are convinced that a GTS is turbocharged and will try and find the turbocharger. Proving that it's not will simply mean telling them that you modified the car to be non-turbo and then expect defects for an non-engineered engine mod, and possible fines for driving a modified vehicle even if the car is equal to or lower than the performance of a GTS.

My suggestion:

1.

Buy a GTS, keep it fairly standard and clean till you're off your P's then buy a GTSt or GTT.

2.

Buy a GTS, upgrade suspension with coilovers or lowered springs, whiteline sway bars, wide wheels with good tyres (even Kumho KU31's are a respectable budget performance tyre), hi-flow panel filter.

Learn to get the most out of driving it in its N/A form, do other supporting upgrades along the way like 5 Stud GTSt Brake Upgrade, gearbox, LSD.. then when you're off your P's buy a a DET with loom and drop that in, or do a DE+t Conversion.

In fact, buy an R33 GTS, then down the track buy an R33 GTSt Front-Cut Complete with Gearbox, wiring loom and ECU if possible, brakes/hub assembly, and wiring loom etc... This way you can do your handling upgrades like the suspension, brakes, wheels and tyres while you're on your P's, all you'll need to do is source 5 stud hubs and brakes for the rear, then when you're off your P's drop in the RB25DET, wire it up, use the stock ECU to get you going or run an aftermarket ECU such as a PowerFC, or piggy back with a GReddy EMU (good if you don't have the GTSt ECU), or possibly Nistune? (someone confirm if you can Nistune the GTS and GTSt ECU's) and then yeah you'll be set to go!

Then sell the old engine, you might not get a lot for it unless someone wants it to to a rebuild or a DE+t set up in a Silvia for example... but yeah, buying an R33 GTS and a half-cut would get you the best of both worlds till you're off your P's. OR just buy and sell and buy again :D

NISMØ Community Regular

NISMØ

Posted
Posted

no, you can do it , but its still illegal to drive it. someone needs to make a sticky topic for this, dumb f**ks seem to ask it every fort night. if you don't know the answer to this basic question, you should not own the car in the first place if you ask me.

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