Turbo Discussion using BorgWarner Matchbot software for 2226cc engines & EFR Turbos

[s2_wot]

Don't forget, that's all theory.
It's good to approximately know what to expect rather than going in blindfolded, but in practice there are lots of other variables...
For example I am pretty sure your air-air intercooler is not going to have over 90% efficiency if you are not running water injection of some kind...

Agreed re the theory and we've all got to learn to deal with the variables. I've never seen the temperature of the air after compression shown in a chart like that previously. I'd have always figured there'd be a few degrees but not hundreds.

On the graph that you have posted in this thread you have 2 lines shown on the compressor map. In both cases they are a long way from the surge line. Is there a reason for this? I've noticed that small changes in the ambient temperature can push the dots closer to this line, is that you're reasoning? How close is too close?

[prj]

Shane, one line is from the stock boost profile and the other from 034 Stage1+ profile.

Theory to practice, here is one graph from a car I mapped.
The engine was not stock at all, but you will have a slight idea:



It's a tad too rich on boost in this graph.
But you will get a better idea on real-world boost profiles from it.

[quattro84]

Nice, squirrell performance had a similar online sheet to mess around with.

PRJ, How far are you in hacking the Motronic? As in: Can you find out and log what the MAF's calculated flow output is..? Don't know about it's accuracy though

[s2_wot]

Boost curve looks smooth, even on this run I can see your argument about the intercooler efficiency you've got a ΔT of 8°C from start to finish.

Can I assume that this was with an upgraded intercooler too?

[prj]

Boost curve looks smooth, even on this run I can see your argument about the intercooler efficiency you've got a ΔT of 8°C from start to finish.

Can I assume that this was with an upgraded intercooler too?

RS2 Intercooler.

PRJ, How far are you in hacking the Motronic? As in: Can you find out and log what the MAF's calculated flow output is..? Don't know about it's accuracy though

Yes. I know enough to write down the entire MAF->Base injection time calculation on a piece of paper with a pencil. In ASM if need be.
Without it I would not have been able to develop the hardware modifications and software calibrations to use the newer HFM5.

It's not really that interesting to log actual MAF flow though. You just log actual vs requested AFR and get them close.

[s2_wot]

Would any body care to review this layout, it's similar to some of the previous with increased more realistic exhaust back pressure, decreased intercooler efficiency, VE as per JP.

Is plot point 2 @ 3000rpm likely to be achievable based on experience?

EFR 6255 58mm Turbine with 0.92 A/R

The wastegate seems to be choked but with my limited experience I can't see a whole lot else wrong with it.

All comments welcome the target here is early boost with say 380 / 400 top end.

[s2_wot]

Here is a graph comparing theory to the actual results of hoffer's car on the Dyno last weekend.

[s2_wot]

Same turbo as above with increased turbine efficiency at lower engine speed based on the assumption that a wagner evo exhaust manifold will deliver an improvement.

EFR 6258 with 0.92 A/R requiring a T4 manifold flange

EFR 6258 with 0.65 A/R requiring a T25 manifold flange



I want to try one of these now

http://cgi.ebay.co.uk/Borg-Warner-Tu...#ht_869wt_1110

The Borg Warner EFR 6258 is the smallest turbocharger in the ultra-efficient EFR lineup. The 62mm OD compressor has a 49.6mm inducer at 44lb/min max flow - supporting up to 440hp with very large map width for outstanding power potential even at high boost. The 6258 is the fastest spooling Borg Warner EFR turbo - and fits in a small package. Ideal for small engines in single turbo configuration and stock internal or modified engines. This is an excellent turbocharger for autocross, rally, drift, road racing and street driven applications. The low inertia 58mm Gamma-Ti turbine wheel is optimally matched for maximum response and fastest spool with the FMW compressor wheel. Borg Warner EFR 6258 uses the smallest-sized EFR compressor housing, fitting in the tightest engine bays particularly twin turbo V6 applications. Ideal for use in single turbo applications for the 260-440hp range, or as twin turbo applications 400-700+hp. Ceramic Ball Bearing only, watercooling recommended (not mandatory).

Compressor Specifications:
Compressor Type: Forged-Milled Wheel (FMW) Extended Tip
Compressor Wheel OD (exducer): 62mm
Compressor Wheel Inducer: 49.6mm
Max Flow Rate: 44 lb/min
Built-in BOV: All EFR compressor housings incorporate an integrated BOV
Compressor Housing: 2.5'' inlet, 2.0'' hose coupler outlet

Turbine Specifications:
Turbine type: Low Inertia Gamma-Ti Turbine Wheel
Turbine Wheel OD: 58mm
Stainless Steel Investment Cast Housing
0.64 A/R T25 Undivided (Internal WG)
Turbine outlet: GT-Vband (aka small 3'' vband) ~92mm OD for all EFR turbos

Features:
Dual Row Ceramic Ball Bearings - lowest friction and fastest spool/response, most extreme durability, built-in oil control orifice - (aka oil restrictor) **no restrictor can be used with EFR turbos
Watercooled Center Section - watercooling is recommended, 14mm banjo bolts
Double seals on both turbine and compressor end for extreme durability and resistance to any oil seepage
Boost Control Solenoid Valve Integrated to Compressor Housing
Integrated Speed Sensor mounting provisions

[s2_wot]

To enable a closer look at how boost is built I've cheated the thing to increase the resolution. These are all using the EFR 6258 with 0.65 A/R.

2000 - 3000 RPM

3000-4000 RPM

4000-5000 RPM

5000-6000 RPM

6200-7000 RPM

No doubt there are some errors in these

[Billman]

Shane, one line is from the stock boost profile and the other from 034 Stage1+ profile.

Theory to practice, here is one graph from a car I mapped.
The engine was not stock at all, but you will have a slight idea:



It's a tad too rich on boost in this graph.
But you will get a better idea on real-world boost profiles from it.

what engine specs/turbo was there?

[Greg_S]

Which turbo did you go for in the end shane?

[s2_wot]

Which turbo did you go for in the end shane?

Greg the 1st problem with any of these turbo's is that they either need a T25 or T4 flange on the exhaust manifold and wagner cannot provide any that suit. Of course this problem can be overcome in a number of ways but I ceased having any interest after exchanging a few messages with Carsten in Wagner.

In my case I've an MTM item on the shelf if I ever get to fit it. It's a sort of a mongrel but should be good for 300+ or thereabouts.