Vr4's potential (hp)

[ASBJÖRN]

Hi,

In my research about upgrated engine we have said me that noone bolt on kit are available for our Vr4 tt.

So I have many question.

Stage one:
Free exhaust
best induction (as stock)
remapping (with what... AVCR, or E manage or...???)

Stage 2:
bigger injector
more turbo's pression


Stage 3 : mono turbo conversion

I would like your opinion about these stage and, for you, how many hp can we have with these different step of engine development?

I would abot 350/400hp at whells...

NB: the galant's vr4 is the same as Gto??

Regards,

[Nick Mann]

The galant and GTO VR4 are different engines. The galants is reversed 180 degrees compared to the GTO and has 2.5 litres compared to the GTO's 3.0.

Exhaust, remap and induction will give some gains, but not much. Increased boost will give more. Expect 300-320 at the engine with all those mods.Wheel horse power depends largely on your transmission losses - 2WD vs 4WD, manual vs auto.

Injectors will cope fine with those power levels - with increased fuel pressure and proper control, they should be good for 400 bhp, but as I said in another thread, the stock TD03 turbos cannot support the air flow required to meet that power level.

[ASBJÖRN]

Ok, thanks for reply...
So we can reach Td03's limit rapidly...
After these limits, what the best, mono turbo conversion, or stay with 2 turbo?
I have see that someone have do the upgrated with one TD05...
But with the mono turbo, mustn't we do a big reprog... E manage is required or no?

Can we stay with twin turbo system with biggest turbo as Td03?

[Turbo_Steve]

In terms of ease, a TD04 swap is probably simplest: a couple of people have actually done it, and apart from some relatively minor plumbing issues, it's less involved than a single turbo conversion.

A pair of TD04s should be able to make 400bhp efficiently, though I would imagine the standard intercooler starts to struggle at these power levels. The larger turbos will run cooler, however, and of course the relative boost pressure will be lower.

The problem with going for larger power outputs is driveability: VR-4s aren't ideal cars for going super-mental-fast: they're relatively heavy and unaerodynamic. The beauty of these cars is their power vs handling vs practicality, and bigger turbos (either single or dual) potentially changes that.

If you want a big power legnum, I doubt there is much stopping you, it's just how big your wallet is
But if you're looking to go 500bhp fast for as litlte money as possible, there are cheaper ways.

[Gowf]

The TD04 swap is possibly more difficult than the single conversion. BUT it all does depend on what turbos you run, as the TD04 flanges are not all the same... Its been said before, and i have found out the hard way, that subaru TD04's would be the easiest to put on but there is still a hell of a lot of modifying to be done to get them on. As for mapping, if you are changing the volumetric efficiency at all you really should remap... therefore if you dramaticaly change it as in fitting bigger turbos then it is essential. Im not sure how they would run on standard management (i havent tried it, and neither would i want to).
Power figures though..... A GTO (yes it does have an extra 500cc displacement) has made 480bhp on a pair of TD04 9B's. So personaly, between 400 and 450 should be a comfortable target, however you are then in the realms of what the standard internals can take.

As Turbo Steve just said, due to the lack of aftermarket bolt on bits, this is not a car that you can just throw a grand at and get amazing results. You can get a relatively quick car with boost controller, fuel control and induction. If you want huge tunability for little money, buy a skyline.

[valmes]

(1)they're relatively heavy and (2)unaerodynamic

Yeah, right...

(1)
3000GT VR-4 - 1680 kg
300ZX TT - 1560 kg
Legnum VR-4 - 1530 kg
Evo 8GT - 1500 kg
Supra TT - 1490 kg
Galant VR-4 Type V - 1480 kg

(2)
Legnum Cx = 0.33
300ZX TT Cx = 0.32
Supra TT = 0.32
Galant Cx = 0.29
3000GT VR-4 Cx = 0.29

[Turbo_Steve]

okay okay, but let's not forget that you can change huge parts of those cars for carbon fibre, plastic windows, aero-kits, turbo kits, high-speed undertrays.

And aerodynamics is more than just drag, it's stability: all the cars you've mentioned have air shaping to increase loading on the front wheels at speed, and goodness knows how much crosswind management.

And you've missed out the subaru / Evo class cars.
Take an Evo 7 and stick a RC Developments stroker kit and a GT40 turbo on it (and all the other gubbins to go with it) and you're looking at a cheaper and more proven solution than the VR-4s. Saying that, if you can afford to do the work, the Legnum / Galant is an awesome car that would be lovely with more power. I'd love to see an RS4 chaser on my drive.

Guys, I've got a scoob TD04 in the garage and offered it up to the existing (weenie!) turbos....it doesn't look that different? Is it just the flanges? I'd quite like to get my hands on a TD03 to see if a ported exhaust housing would accept the TD04.

Assuming you can keep the boost control sensible (i.e. non ECU) then the standard management should...just about cope.
As it works on MAF rather than MAP, the engine load is calculated as the Mass of air, i.e. turbo flow rate rather than having to calculated from boost pressure using the flow rate as a "constant" (and the temperature).

It should drive, and safely: though it may not be very responsive, as the load points that bring the TD03s on boost will be long gone by the time we get to Td04s optimum range.

Watching a boost guage lash up today, the TD03s are crazily small: partial throttle normal driving and they're already making positive pressure! At less than 50% throttle!! No wonder it's thirsty driven normally: peak flow rate on throttle changes must be way above the MAF / ECUs ability to cope react: I want to get a wideband on there, as it must slosh fuel in there everytime to vary the throttle.

Mine actually seems to be more economical driven hard (lots of accelerating and braking) than cruising, which is just madness!!
Full credit to Mitsi for building an amazingly responsive turbocharged engine, but I'm not convinced they got the compromise quite right.

This is, without a doubt, one of the best cars I have ever owned, and technically definitely the most interesting!

[Gowf]

The TD03 housing would need one hell of a lot of machining. Im fairly convinced, although i may be proved wrong, that you wouldnt be able to do it.

As you can see with the scoobie tub, you could modify the flange of the manifold/turbo to get it to fit.

Yeah i do agree that it runs rich enough as standard to cope with the bigger airflow, but there is a limit to that, so it all does depend on how much air you want to be pushing through.

[mitchy]

i've only just received my legnum, and i have a mate with a gto who is going the 'big single' route...

but it seems to me a big single would be an easier option, rather than messing around with twins..
i havent looked at the manifolds properly, but on the gto you can just get 2 of the same side manifold to point them to the left of the engine bay, then have a manifold made up from those two, to the single manifold.

on the legnum it seems this would remove alot of the piping which is basically what seems to clutter up the engine bay, so along with a new ecu, fmic, intake piping, exhaust, turbo, manifold and fueling upgrades, you'd be well on your way

i'm not saying its EASY, no way.. but perhaps easier than twin TD04's?
prove me wrong if thats the case, but its just an observation i've made.

[valmes]

This debate, twins vs single, was brought up for a number of times... search the forums and you'll find arguments that swing either way. I am from the twins camp ... so to say. IMO, V shaped engine is better suited for two turbos. But, each to their own - if you think you absolutely need to make it single - go for it!

Guys, I've got a scoob TD04 in the garage and offered it up to the existing (weenie!) turbos....it doesn't look that different? Is it just the flanges? I'd quite like to get my hands on a TD03 to see if a ported exhaust housing would accept the TD04.

Than you were probably looking at the wrong TD04... they do differ a lot and you should skip the tiny td04-9bs... since they are only marginally better then our stockers:

TD03L-7T ~ 250 CFM
TD04-9B - 275 CFM
TD04-13G - 360 CFM
TD04L-13T - 405 CFM

I think for the simplest, almost bolt on upgrade, you will have to source the cartridges from new BMW 335 installed TD03L-10TK3 (49131-07005) turbos and put them into the stock VR-4 turbo housings... they were proven to make a bit over 380hp on a BMW... that means they can SAFELY flow enough air for VR-4 to make the same power.

[bradc]

But do we know if the BMW flanges are the same as ours?

Steve - as far as the turbo size goes - I can floor it in 5th gear at 1500rpm and lift off at 1800rpm a few seconds later, and the blow off valve goes! I don't have a boost gauge so I don't know how much pressure I'm making, but yes they are stupidly small. Mitsi should have used TD04-9B's from the start, they would have made the cars better on fuel, more satisfying to drive, still made boost early on, and most importantly for us would have allowed us to bolt on much bigger turbos.

[valmes]

No Brad, you missed the point. There are no flanges on BMW... they are integrated into exhaust manifolds... but that doesn't stop you from using the cartridges... since turbo is usually made up from 3 pieces - turbo housing, compressor housing and rotating assembly - cartridge. So you can basically source the cartridge and put it in VR-4s compressor and turbo housings.

[bradc]

ahh right.

Probably easier to buy TD04's rather than trying to convince BMW to give you some turbos Unless anyone is up for 'borrowing' a 335i and returning it to BMW in N/A form

[pitmac]

Valmes,

Re TD03L-10TK3 cartridge do you think the turbine wheel would fit the Turbine housing and the compressor housing would have to be machined to suit.

[valmes]

ahh right.

Probably easier to buy TD04's rather than trying to convince BMW to give you some turbos Unless anyone is up for 'borrowing' a 335i and returning it to BMW in N/A form

They are also after upgrades... so when they start changing their turbos - its time to get those deals

... and remember its still a Mitsubishi turbo, you can probably order a new cartridge through BMW, Mitsubishi or some turbo re-builder guys.

[valmes]

Valmes,

Re TD03L-10TK3 cartridge do you think the turbine wheel would fit the Turbine housing and the compressor housing would have to be machined to suit.

There is a good chance that it will... we won't know for sure until someone actually tries it. It's of the same family (td03) and even if a bit larger on either side - a good turbo rebuilder should have no problems fitting it inside the VR-4 td03 housings.

[Turbo_Steve]

I bow to your expertise on the TD04 fitment...I've not really looked harder than "oh that's interesting" as I've been expressly told I'm not allowed to play with it too much (unless it improves the fuel economy).

I'd like to get my hands on an old TD03, though, purely out of interest.

I think the turbo I have is a TD04-14B...from memory? Aside from the exhaust side looking like a bit of a hassle, I didn't think it looked too bad....I'll look again.....

Yeah i do agree that it runs rich enough as standard to cope with the bigger airflow, but there is a limit to that, so it all does depend on how much air you want to be pushing through.

Gowf, as long as you don't 'overload' the MAF (i.e. go off the top of the metering scale) it isn't likely to lean out: It knows how much fuel it needs for a given load (air mass) at a given RPM, and as long as you know your injector duty cycle isn't maxxing out (something like EvoScan should be able to help there) then the only risk is throttle change enrichment, where it's POSSIBLE the turbo could "beat the ECU to it" hitting boost and run lean for a brief moment. However, we've already established that throttle change is where the ECU overfuels, and this is a problem usually associated with fitting smaller, more responsive turbos, not bigger laggier ones.

I'm not suggesting everyone should rush out and try it, but as a "get you home" or "Autronic still in the post" solution it's probably adequate.

I maintain that it would probably be fairly horrible to drive, with overfuelling and possibly a lot of timing retarded out in the areas where it normally comes on boost.

Of course, I guess no one will ever know until someone can afford to try it, which definitely isn't me until next year.

[SGHOM]

I'd like to get my hands on an old TD03, though, purely out of interest.

I've got loads of them strewn all over my house !! help yr'self

[Gowf]

I bow to your expertise on the TD04 fitment...I've not really looked harder than "oh that's interesting" as I've been expressly told I'm not allowed to play with it too much (unless it improves the fuel economy).

I'd like to get my hands on an old TD03, though, purely out of interest.

I think the turbo I have is a TD04-14B...from memory? Aside from the exhaust side looking like a bit of a hassle, I didn't think it looked too bad....I'll look again.....




Gowf, as long as you don't 'overload' the MAF (i.e. go off the top of the metering scale) it isn't likely to lean out: It knows how much fuel it needs for a given load (air mass) at a given RPM, and as long as you know your injector duty cycle isn't maxxing out (something like EvoScan should be able to help there) then the only risk is throttle change enrichment, where it's POSSIBLE the turbo could "beat the ECU to it" hitting boost and run lean for a brief moment. However, we've already established that throttle change is where the ECU overfuels, and this is a problem usually associated with fitting smaller, more responsive turbos, not bigger laggier ones.

I'm not suggesting everyone should rush out and try it, but as a "get you home" or "Autronic still in the post" solution it's probably adequate.

I maintain that it would probably be fairly horrible to drive, with overfuelling and possibly a lot of timing retarded out in the areas where it normally comes on boost.

Of course, I guess no one will ever know until someone can afford to try it, which definitely isn't me until next year.

Yes i agree, but the issue that i was thinking of was fuel/boost cut. It's fairly easy to get the vr4 to do it between 3000-4000rpm. So if you are pushing a lot more air at those given rpm's than the MAF actualy likes then your going to have issues. However, bigger injectors and remap will sort that out without the need for a fcd. It is a bit of an unknown because everyone who does the turbo upgrade will have some different fueling in mind anyways.

[Turbo_Steve]

!!!! PM on it's way !!!!