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I Only Have Low-mid Range Power

rorz

By rorz,
in Engines & Forced Induction

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rorz Enthusiast

rorz

Posted
Posted

Hey guys,

Are rb20det's really slow or is it just me? I recently got a r32 gts4 converted to RWD,

Stock turbo

Stock airbox

No cat

11psi boost

Stock zorst

At about 2500 it starts getting up to 11psi which holds till about 6000 then trails down to about 9..

My issue is, it only seems to give you that 'turbocharged boost' feeling at about 3-3500 then the rest of the gear feels like a NA despite the bost guage reading 11.

After doing a lot of searching on these forums most people complain about no low end but good top end, where i seem to be the opposite..

I used to have a SR20det silvia which was slow in low revs then kept getting faster as the revs climbed higher which is the feeling i like/expect from a turbo car

Any ideas? I could be paranoid and just have a slow 6 cylinder 20det.

Cheers

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bubba Grand Master

bubba

Posted
Posted

Sounds about right for a stock RB20 turbo.

Source yourself an RB25 turbo (preferably a series 1) and wind it up to 12psi.. you will lose some low down but gain a fair bit in the top end and it will pull all the way to redline.

GTScotT Grand Master

GTScotT

Posted
Posted

thats not the feeling i last had from a rb20det with just a catback. as per results last I drove one felt like it had plenty up top and a little lacking down low, the rb25 turbo added to this in both departments.

sounds to me like you are missing your top end action. how long have you owned the car? was it like this from day one?

things to test: fuel reg & fuel pump.

suggested test: crimp the return hose off the reg, see if it does anything. this is to be done for TEST sake only and is TEMPORARY. I wouldnt run the car like that for long.

$10 says its ur reg

rorz Enthusiast

rorz

Posted
  • Author
Posted
thats not the feeling i last had from a rb20det with just a catback. as per results last I drove one felt like it had plenty up top and a little lacking down low, the rb25 turbo added to this in both departments.

sounds to me like you are missing your top end action. how long have you owned the car? was it like this from day one?

things to test: fuel reg & fuel pump.

suggested test: crimp the return hose off the reg, see if it does anything. this is to be done for TEST sake only and is TEMPORARY. I wouldnt run the car like that for long.

$10 says its ur reg

I've had the car about a week so yeah it's always been like this. At first i just assumed the rb20det is slow but after a bit more driving i decided it's definately lacking top end.

In your test you say 'see if it does anything', what should i be looking for here?

Thanks for the replies

bubba Grand Master

bubba

Posted
Posted
thats not the feeling i last had from a rb20det with just a catback. as per results last I drove one felt like it had plenty up top and a little lacking down low, the rb25 turbo added to this in both departments.

sounds to me like you are missing your top end action. how long have you owned the car? was it like this from day one?

things to test: fuel reg & fuel pump.

suggested test: crimp the return hose off the reg, see if it does anything. this is to be done for TEST sake only and is TEMPORARY. I wouldnt run the car like that for long.

$10 says its ur reg

His doesn't even have a catback..

And when my stock fuel pump was dying, it was actually leaning the engine out and making it go harder.

It's been so long since I had an RB20 with a stock turbo so it's hard to remember back that far but, I'm sure it came on a lot earlier than 3500 (that's when the 25 turbo was pulling hard).

rorz Enthusiast

rorz

Posted
  • Author
Posted
His doesn't even have a catback..

And when my stock fuel pump was dying, it was actually leaning the engine out and making it go harder.

It's been so long since I had an RB20 with a stock turbo so it's hard to remember back that far but, I'm sure it came on a lot earlier than 3500 (that's when the 25 turbo was pulling hard).

The pulling feeling in my car is around 3000 im not entirely sure but the point of my post is that that pulling feeling dissappears soon after and the rest of the gear feels like an NA Rb25 if you like.

I'll try the fuel reg thing anyway and let you guys know how it goes tomorrow arvo.

bubba Grand Master

bubba

Posted
Posted
you have a stock exhaust. that will be restricting things in the top end. the cat may also be a bit blocked make it even more sluggish in the top end.

I think he said he doesn't have a cat.

How many km has the engine done? has the timing belt been done? (thinking it may have slipped a tooth or two?)

But yeah, the stock exhaust won't be doing you any favours.. get a full 3" turbo back.

And find someone in your area with another stocker and compare.

bubba Grand Master

bubba

Posted
Posted
Yep i cant do that mate no boost controller, it's boosting at 11psi becuase i have no cat

Doesn't matter if you have a boost controller or not, the stock RB20 actuator is ~10psi, the only way you could go lower is with an R33/34 actuator which is ~5psi but that's just stupid.

My stock ECU handled 14psi with the stock turbo and 12psi with the RB25 turbo.

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