59 replies to this topic

[BAre]

233 RWHP on a two roller Mustang MD250 dyno.

 

Still a lot to go if I raise the RPM some more.

 

42 mm AT Power ITB and STG 4 Comp Cams.

 

[Nev]

Something rather "odd" about that dyno plot, how come the torque and power lines don't cross at 5252 RPM ?

[siztenboots]

torque units are in N-M

[Nev]

ah, hence it crosses way lower.

[TFD]

Thanx BAre. What stage/engine spec was this?

[BAre]

ah, hence it crosses way lower.

 

Nm uses the formula Hp = (Nm x Rpm) / 7121.

 

My dyno sheet dont have Hp and Nm in the same Y aksis, so it will not cross in the same way you are used too.

 

Testing the numbers....: (238 RWNm x Rpm6992) /7121 = 233  RWHP

 

TDF:

 

The engine has original 2.2 bottom with balance shaft delition kit and 5kg flyweel.

Patriot Performance CNC ported head (+0.5 valves) and compcam stg 4 exhaust/stg 3 inlet.

Homemade race hedder tuned to 89 degree BDTC exhaust opening.

AT Power 42 mm shaftless throttle bodies

Homemade inlet manifold.

 

The engine is restrickted to 7000 rpm due to the fact that piston and rods is original.

 

[TFD]

Another question guys,

 

what whp can a vxr turbo push on a 2.2 at 10psi/0,7bar of boost?

Not that familiar with that turbo and cant find comparison since everyone is running overboost and bhp figures.

I'm not gonna run overboost. A steady 0,7/0,8 bar

 

Read stock Astra boost is 14 psi and produces 195ish whp? True? Cause 0,7 bar would not be that great then (170ish whp).

Just checking if I can make 220ish whp with a oem vx220 turbo setup at 0,7 bar. If not than I'll go the garrett route.

 

Thanx!

[Nev]

220 WHP on 0.7 Bar boost is optimistic IMO.

 

0.7 Bar is little more than a small hamster coughing down your boost pipes. Unless you've got HC and good engine breathing seeing 220 RWHP seems rather unlikely to me (doubly so if you are intending to use a SC'er with it's inherent loses).

Edited by Nev, 15 November 2013 - 11:52 PM.

[Nev]

You need a hub dyno like they have at Torque Developments for a WHP figure. Most UK dynos only give a corrected flywheel figure.

 

Just for clarity, a hub dyno still has to use an "estimated" drive-train loss % to estimate WHP.

 

It is one step up in exactness from a normal dyno, but all it eliminates is tyre slippage/friction/rotational mass (not gearbox or drive train loses, which still have to be "estimated").

Edited by Nev, 15 November 2013 - 11:56 PM.

[Bumblebee]

Why do the vx's tend to have over boost? Can't remember if they have it as standard or not?

[TFD]

Astra's have overboost so I reckon VXT's also have this.

 

I did check some more things and my z20let turbo swap idea doesnt work since z20let doesnt fit z22se head. Dont know why I thought this..

Its the Z20NET thats a direct swap. Not gonna do this since the turbo has a weird shape/position so probably have to cut the boot.

 

Gonna build myself a setup now. GT28R should push 220whp easy on low boost. 

[Bumblebee]

Yeah I'm just debating wether to fit my gt28 or not.....

[Rickwoo118]

Yeah I'm just debating wether to fit my gt28 or not.....

go for it Aimy!! I seem to copy your mods anyway....so if you do it I look forward to seeing it and maybe do it myself!

[TFD]

Aimy, still the gt2871r .86 you're talking about right?

Posted earlier on that one. Wouldn't do it for 300hp.... way laggy.

GT28R@ 1bar = 260ish whp and super spoolup. Bit of a flat top end thou

GT28RS@ 0,8 bar = 280ish whp and fast spoolup with great top end.

 

GT2860RS .64 FTW. I'm pushing my luck on stock internals with this turbo so hence the softer GT28R, otherwise.....

[Bumblebee]

It's a gt2871r (Vx specific turbo) I've got a bit of thinking time as my cars been put to bed now until spring

Edited by Bumblebee, 21 November 2013 - 10:05 PM.

[mbes2]

Do it! 

 

Whats the worse that can happen..... 

[siztenboots]

Why do the vx's tend to have over boost? Can't remember if they have it as standard or not?

you don't have to have overboost , its a function of the motronic that it allows it.

[mbes2]

278whp & 339Wtq

 

Z20LET

K04 Turbo

Forged Engine Upgrade

Wossner forged pistons & rods

Polished & skimmed head

Balancer Shaft Removal

PA Chargecooler

Full Tullet 3" exhaust system, Front pipe & 200cpi sports cat

Alloy Intake Pipe

Alloy High Flow Plenum

VXR High Flow fuel Injectors

Stage 4 cool running plugs

Helix 4-paddle clutch

Apexi Universal Power Intake Filter & Flange 80mm

Z20LEH 80mm AMF

80mm pipe work

Lightened & Balanced flywheel 

MBR Custom Map

 

Edited by mbes2, 13 April 2014 - 01:51 AM.

[manus]

What are the wheelpower figures you guys are running with these tuning stages

Depending on the dyno itself, a rough rule of thumb for the vx/speedster is to deduct 15 to 20% horsies to convert from crank to hub. Generic rule of thumb is anything between 0 and 30% loss iirc.

Some Dynos will calculate loss for you (Reving down) and will produce accurate flywheel hp's.

Edited by manus, 13 April 2014 - 07:10 AM.

[Nev]

278whp & 339Wtq   Z20LET K04 Turbo Forged Engine Upgrade Wossner forged pistons & rods Polished & skimmed head Balancer Shaft Removal PA Chargecooler Full Tullet 3" exhaust system, Front pipe & 200cpi sports cat Alloy Intake Pipe Alloy High Flow Plenum VXR High Flow fuel Injectors Stage 4 cool running plugs Helix 4-paddle clutch Apexi Universal Power Intake Filter & Flange 80mm Z20LEH 80mm AMF 80mm pipe work Lightened & Balanced flywheel  MBR Custom Map

Cricky, 339 wheel torque in ft/lb?? That's a lot. For the OP, its normal to consider drive train losses on the VX220 (with an F23) to be approx. 9% to 11%. Thus you can take dyno BHP/torque and divide by 1.1 (approx.) to get the wheel BHP.

Edited by Nev, 14 April 2014 - 08:00 PM.