edomund

1st off Yes I searched a lot.

I have a 87 TII with a BNR hybrid turbo stage 4 I believe.
T04E 60:1 AR, stock hot side, clipped turbine, ported wastegate and turbo manifold.
I mostly run around 12-14 PSI on this setup.

My question is should I run the vspec core or rspec core?

I read the greddy site so I know the differences in the core design thats not what I'm concerned with. I want to know if my turbo application would be better for the vspec (stock turbo application according to greddy) or if my setup is better suited for a rspec core.

Thanks,
Ed

1987RX7guy

iTrader: (3)

IMO the Vspec will do just fine, but the Rspec would be even better.


Given you have the larger compressor, its likely got a better efficiency at the higher boost levels than the stock compressor. I think the Rspec is more likely to be for larger turbos like T78/T88/etc.

classicauto

iTrader: (3)

I would tend to agree with that.

I believe though in this particulat app. neither would make or break the performance, the biggest difference for that setup would be length of I/C piping and I/C configuration....meaning he's gonna see more of a difference with a V mount as oppose to choosing between two different front mounts.

edomund

I actually like the piping config of the rspec because it goes straight down from the compressor (you have the clock the turbo 180 degrees down). This would help clear up space for my custom 3" TID I made. It looks like the Vspec piping is in the way of where my AFM and filter sit behind the passenger headlight.

The thing I was concerned about is that some have said the rspec has more pressure drop. I am only running 12-14 psi.

So am I going to actually lose power with the rspec core as apposed to the Vspec core?

Ed

classicauto

iTrader: (3)

its possible, I would look for someone running either core and ask them...although thats probably the purpose of this thread right?

But I would imagine that either one will have a slight pressure drop compared to....wait, what are you running now? factory TMIC?

edomund

My TID location

edomund

Yeah I'm running a factory tmic now.

edomund

Here are some rspec pics
There is actually a lot less piping in the rspec kit since it goes straight down to the intercooler on the turbo side wouldn't this reduce lag?

So anyone know if I will lose power with a rspec kit compared to the vspec kit with my setup (read above)?

Ed

ilike2eatricers

I have the vspec kit and dont notice any lag at all compared to stock TMIC. The rspec core is supposed to be for higher hp applications and has different flow characteristics. It is also a 3 row compared to the 2 row vspec. The thing is the vspec is made to be used with stock turbo application fitment wise while the rspec is designed for use with a greddy turbo kit. You can easily make it work though. If price isnt a factor it's up to you. People have made plenty of power with the vspec so I dont really see a need for an rspec but I'm fairly confident to say that you will not lose power over getting a vspec, if anything you may gain some because of a better flow design.

eriksseven

iTrader: (6)

Kind of an off-shoot question, but; what are you running in terms of engine managment? I notice you're specifically interested in preserving your TID/AFM setup... AFM leads me to believe you're running a piggy-back application of some sort?

edomund

Yeah Apexi S-AFC and a LM1 wideband computer, I haven't gone standalone.
4 720CC injectors

RETed

If you can afford the R-spec one, get it.
The V-spec one is supposed just for stock turbo applications.


-Ted

edomund

Reted I respect & apprecite your opinion. More help and elaboration would be greatly appreciated.

So I shouldn't lose any power with the rspec vs vspec because I am running relatively low boost levels? Greddy says vspec <15psi and rspec >15psi.

I would rather run the rspec becuase of the shorter piping and the route of the compressor side pipe to the intercooler.

Ed

RETed

Ok, this is the no-bullshit opinion on the R-Spec versus the V-Spec cores...

The R-Spec core is a traditional, internal finned IC core.
It's proven, and it does it's job well.
The downside is that due to the internal fins, pressure drop across the core is significant.

The V-Spec core / IC was designed for car owners who run small / stock turbos who wanted that big, in-your-face IC sticking out on the front of their cars.
The problem with running a traditional, internal finned IC core that big, up front, is that the pressure drop is just too big.
(Running the stock turbo through a 24R would probably have 2.0+ psi of pressure drop, I estimate.)
So, Trust / GReddy designed the V-Spec core which solves all the problems.
With the "microfin" design, pressure drop is minimized, but this also drops heat transfer abilities - so there's the trade-off.
But, the V-Spec IC is so big, that for moderate boost levels, it does an okay job - just don't use it for 20psi+ applications!
This is why GReddy states those recommendations for boost levels.

Bottom line?
The R-Spec IC core is more efficient for heat transfer - the primary responsibility for an intercooler.
Stock turbos or boost under 10psi, the V-Spec is fine.
There used to be a $200 difference in price between the two versions, but "street pricing" has made the difference drop to under $100.

Intercooler pipe routing should not be your primary concern.
The 24R IC kit was never meant to run with the stock turbo - it was initially designed for their TD-06SH turbo kit, so I'm a little bit surprised that the piping is "shorter" than the 24V kit.


-Ted

edomund

Ok I understand all of that but you say vspec is ok just not for 20psi +apps then you say it's ok for 10psi or less. I'm in the middle I have a hybrid running over 10 but less than 20.

So bottom line could you tell me which one you would run a vspec or rspec with my turbo setup. (BNR stage 3 Hybrid 60:1 TO4 turbo at 12-14 PSI)

Thanks
Ed

RETed

This is why I said...

"If you can afford the R-spec one, get it."



Under 10psi, the V-Spec is fine.
If you're getting close to 20psi, then the R-Spec is highly recommended.
15psi could go either way, but like I said above, if you can afford it, get the R-Spec.

When you start to head into 15psi and higher boost, the intake charge gets really hot.
This is where the superior heat transfer abilities of the R-Spec core will be significant.

For stock turbos, no reason to go with the R-Spec unless you got money to burn.

For big hybrids (yours is considered a "big hybrid"), I would recommend the R-Spec core, especially if you're doing 10psi+ boost consistently.

Does that answer your question?


-Ted

bigdv519

iTrader: (3)

How about running the V-spec kit with a 2 row R-spec core? The piping would bolt up to your stock/hybrid turbo and there wouldn't be a huge pressure drop across the 2 row R-spec, as compared to the 3 row R-spec.

edomund

Yes reted thank you it does I just realized you already said that
But thank you for clearing it up.

bigdv519 I'm not going to run a 3 row rspec core. I'm talking about 2row rspec vs 2 row vspec.

I'm going with the 2 row rspec. The piping will actually work ok with my hydrid I just need to clock the turbo 180 degrees.

Ed

RETed

You basically turned your 24V kit to a 24R kit.
Seriously though, I dunno what the big hang-up is with the piping.
This is the first time I've heard of people seriously debating the pipe routing on these kits.
Getting a welder to custom fit pipes shouldn't be that big of a deal.


-Ted

bigdv519

iTrader: (3)

Oh no no, I'm not worried about piping. I assumed (<--my mistake) that he was referring to the R-Spec 3 row kit, since it wasn't mentioned anywhere else in the thread.

Edit: Get the 2 row R-spec then, there is only a $60 difference in the 2.