+400hp ?

[audiman]

How did you measure back pressure?? any pictures of the setup. That some thing that i would like to see on mine. Next time its power is wound up.

[TURBOKONGEN]

What are the specs on the turbine .
Is it this ? :
-Wheel: 53.85mm w/ 76 trim
Is the turbine outlet diameter 41.7mm or 47mm ?
If you are using the .64ar with 41mm outlet , I really can not understand what you have done to get this amount of power , and with so low back pressure .
Incredibly impressive numbers .

[audiman]

What is acceptable back pressure then?? I run a KKK 26/27 #8 and hold 1.55bar at redline, just wondered how far we can push it, if i could measure the back pressure then i can see how much more we can go.

[Mihnea]

Tom, a generally accepted backpressure idea is a 2:1 ratio with manifold boost. i.e. 3.1 Bar exhaust backpressure after the turbo is acceptable on your car

Cheers,

M.

[repo]

How did you measure back pressure?? any pictures of the setup. That some thing that i would like to see on mine. Next time its power is wound up.

I drilled 2mm hole through a brake pipe fitting I welded to a collector. The I put in some 30cm of metallic brake tube and extended it with normal rubber hose. I used liquid-damped pressure gauge to avoid needle vibration.

Turbokongen - This was with 47mm exducer.

Mihnea - I have kept 1.5 x boost as a rule of a thumb for max backpressure, although I think 2:1 would be acceptable in certain circumstances. I general when EGT's stay low without running super rich. (as obvious)

BTW what kind of equipment do You Mihnea use listen pinging while tuning? I used banjo adapter screwed on intake manny's grounding point, and attached silicone hose into it. To listen the noise from the engine I have a Hazet stethoscope to attach into that hose. Works fine, although I think the proper place for that banjo would be under the bolt the Motronic knock sensor is, but it's kinda tricky place to install it afterwards...

[TURBOKONGEN]

A friend of mine just had his Nissan 200sx s13 ca18det (1.8l) mapped and dynoed using a GT2871R .86ar .
They got 390whp at 1.6 bar boost . This was with a conservative mapping done on regular street petrol .

[Tommy200rs]

Mika tuned 3 20v 5'ers that day.

RS2 with gt2871R: 458hp/519Nm, (513Nm @ 3700rpm) with lots of surging problems at spoolup.

Pekka's S2

And finally one bone stock 3b with Holset H1 54in/65ex: 450hp/537Nm with 1,6bar boost.

Some additions from ATP www pages:

Pekka's S2

Dual Ball Bearing GT25/40-R Turbo assembly with specified ar. T25 style inlet flange with 5 bolt style exit. Large 60- 1 style compressor housing with 4.00" inlet and 2.50" outlet. Very Good response turbo for 4 Cyl applications. This turbo has a flow capacity of about 450HP.

Turbine
-Wheel: 53mm w/ 62 trim
-Housing: .64 ar, .86 ar
-Maps: Not Available

In dyno it was with .86 turbine, bosch blue injectors. stock aby IC.

If there is selection process either RS2´s gt2871R or the S2´s GT25/40-R, I might consider the GT25/40-R, because it did not have the surging problems with factory cam settings (ABY inlet + NM ex). Selection process is difficult because the cam settings with the RS2´s gt2871R (was with .63 housing in dyno) were not fully optimized. Now the cam settings in rs2 are better and there is considerably more low end torgue/power at 3000 rpm onwards. Very difficult to select but if purchasing now and knowing the history, I would bet the Race horSe with GT25/40-R with .63.

Another thing is that the cross hatches (to kill the turbulences inside inlet piping before maf) before MAF are VERY crucial. The Air filter solutions and positioning and "mud shielding" of filters are the most important things for longer engine life expectations.

Pekka sold his S2, when the project was ready and fine tuned with rs2 injectors and the .63 turbine housing and now a new owner is mastering the car. Both cars have not visited dyno after the latest mods.

[Erikb]

How does these compare the gt25/40-r / gt2871r / gt3071r, considering low rpm torque and max output?

[Greg_S]

Have we got anymore news on the GT2871 and comparison with the GT3071. I aim looking for max driveability across the rev range without loads of lag and a stead torque curve

[Gringo]

No more worries about maf´s reliability.

Not to burst your bubble here, but the SportQ MAF that was in my car didn`t last one summer .....

It was located about 90 degrees off the turbo intake, 30 cm away, supported by a brace, and the inlet tubing had the cross-hatch mod. So don`t get your hopes up to much. Btw; It was also scaled for MTM program and running a K27 "motorsport" turbo.

[S4turbo]

Repo, digging up some old info here. Yoy mention good cfm/hp ratio, what can be done to an enginge to improve this?

Regards, Johan

This restrictive action was made du to the fact of bad port job made by previous engine workshop.

I saw Mihnea mentioning surging probs of Garet ballistic turbos in some thread, and appears that he is right (as usual?)

Solution for this feature (rather than a bug) would be enhancing air consumption of the base engine at 3000-4000rpm area; cam timing, or different cams maybe.

the key to reasonably big hp figure is good cfm/hp ratio, which is close to 1.47 in this particular engine. As Teppo mentioned, we gained one hp with 2bar boost, indicating total run out of compressor flow. You can also see this from the compressor map.

Exhaust backpressure was some 2.2bar at +7000rpm.

I'll post holset - 3b-setup dyno plots when I get one. This setup was intentionally made to rock at high rpm range, due to stock internals, and purpose of the car (circuit racer).

[Jamo]

I drilled 2mm hole through a brake pipe fitting I welded to a collector. The I put in some 30cm of metallic brake tube and extended it with normal rubber hose. I used liquid-damped pressure gauge to avoid needle vibration.

Turbokongen - This was with 47mm exducer.

Mihnea - I have kept 1.5 x boost as a rule of a thumb for max backpressure, although I think 2:1 would be acceptable in certain circumstances. I general when EGT's stay low without running super rich. (as obvious)

BTW what kind of equipment do You Mihnea use listen pinging while tuning? I used banjo adapter screwed on intake manny's grounding point, and attached silicone hose into it. To listen the noise from the engine I have a Hazet stethoscope to attach into that hose. Works fine, although I think the proper place for that banjo would be under the bolt the Motronic knock sensor is, but it's kinda tricky place to install it afterwards...

Been looking for this post last few days, nice way to measure back pressure in the exhaust system

[my2000apb]

did you find the holset/3b plots?

[zafra]

Have a pictures of em? Im considering make one, i dont know the benefits of external or internal Wastegate.

[Jamo]

Guys this is a 9 year old thread