Dyno RS2 comp 458 AR :63 3B

[JP]

is there a way to port the head to increase spool rather than delay it?

Yes and no, to achieve that you need to purposely unbalance the head, which makes it more prone to surge on a big turbo. On a small turbo you can get away with it. But all you will gain is midrange and no real top end gains. Realistically a properly pirates head won't make it spool faster but produce more hp per psi of boost giving smoother power delivery with improved midrange and top end. So it will give the feel of quicker spool due to improved power figs.

Espen, what would you consider the proper scale to graph on a Dynojet plot then? there are many choices... Uncorrected, SEA, DIN, EEC, STD, JIS?

here is mine for example
in Uncorrected it was 621.24 / 437.79
in SAE it was 599.13 / 422.21
in DIN it was 617.58 / 435.21
in EEC 598.82 / 422.00
in STD it was 616.62 / 434.54
in JIS it was 600.67 / 423.30

this was @ 8600 and 2.3BAR (330 kpa on the log) for my 4cyl 20vT.

just wondering, as i read soooo many people throw the terms around that this dyno is wrong, that dyno is wrong, etc. Mustang over DynoJet, DynoDynamics over Mustang, etc. i have tuned on Mustang, DynoJet, and DynoDynamics.

hell, here in USA Florida has the HIGHEST DYNOS AROUND! averaging an extra 40+ WHP! haha.

just wondering. thanks.

Weve noticed this issue for comparison ourselves. In approx a fortnight when the new driveshafts have been fitted on my mates mk2 we are going back for a final map by tweaking the cams.

Once mapped up on the Dyno Dynamics we are taking a roadtrip upto MRC to run the car up on a cartec for comparison. After which we are driving to Manchester to put the car on a Dynojet. This way we can have a look how the figures compare between the various dyno's with respect to whp and calculated flywheel.

[JP]

Engine is ported with furans race intake, big intercooler and free flowing filter Adu cams clocked,

We are thinking exhaust back pressure

Exhaust backpressure normally doesn't cause surge it normally makes spool up slower.

I did a dyno run Fri night on a cartec on a gt30r with .63 backhousing.32psi till redline no surge on a 5th gear run. We had to stop though due to a lean spike which was discovered to be due to a low supply voltage to the fuel pump.
I've also ordered a .82 backhousing to reduce high rpm EGT's on trackdays. So will see what it does then.

As for the rest of the spec, £60 eBay special intercooler, 60mm boost run, AAN intake, ported head and clocked 7a cams.

I'll post a plot up when I get home from b4 and after the cams where clocked.

Assuming your head has been correctly ported (as I've seen many with exh gains but int losses) I'd put it down to the cam setup.

[EspenW]

Espen, what would you consider the proper scale to graph on a Dynojet plot then? there are many choices... Uncorrected, SEA, DIN, EEC, STD, JIS?

here is mine for example
in Uncorrected it was 621.24 / 437.79
in SAE it was 599.13 / 422.21
in DIN it was 617.58 / 435.21
in EEC 598.82 / 422.00
in STD it was 616.62 / 434.54
in JIS it was 600.67 / 423.30

this was @ 8600 and 2.3BAR (330 kpa on the log) for my 4cyl 20vT, in 3rd gear.

just wondering, as i read soooo many people throw the terms around that this dyno is wrong, that dyno is wrong, etc. Mustang over DynoJet, DynoDynamics over Mustang, etc. i have tuned on Mustang, DynoJet, and DynoDynamics.

hell, here in USA Florida has the HIGHEST DYNOS AROUND! averaging an extra 40+ WHP! haha.


just wondering. thanks.

I prefer Mustang numbers, as they are loaded to match what is happening on the road. A pull on a properly calibrated Mustang will match rpm/s from datalogging on the road in the same gear.
Newer Dynojets are better than the old ones, and they overstate less with higher hp levels. Reason is that since they are unloaded, higher hp cars will go through the pulls faster, thus more power is absorbed by inertia. If on an unloaded Dynojet, I would definitely use 4th gear.
I use SAE correction, but correct to PS (divide hp by 0.985) when required.
Only correct 50% for altitude and barometric pressure on a turbo car, so if dynoing at 1000ft, one would enter 500ft for the SAE correction.

[EspenW]

Once mapped up on the Dyno Dynamics we are taking a roadtrip upto MRC to run the car up on a cartec for comparison. After which we are driving to Manchester to put the car on a Dynojet. This way we can have a look how the figures compare between the various dyno's with respect to whp and calculated flywheel.

Awesome. Make sure that you get the whp numbers, as some dyno operators hesitate to provide these..
Turbo Magazine did this and got numbers ranging from approx 228 to 265whp on the same car on the same day, depending on type of dyno:

http://www.turbomagazine.com/tech/0306tur_turbo_magazine_dyno_dash/index.html

[A80Avant]

nice!, im getting something like 1.2bar on 3340rpm on 4th. not bad for the 0.82AR

[gnutz2]

@ RWD19T

Do you have any info on dialing in the 7A cams.

Do you have vernier sprockets or just a pulley and did you advance retard? how many degrees??

Thanks.

[jade]

nice!, im getting something like 1.2bar on 3340rpm on 4th. not bad for the 0.82AR

Car drives well boosts quickly, but will have to resolve this problem with the surge, I will Look at the cams as suggested, I have not had a chance to measure exhaust back pressure yet, other options are possibly a bigger hot side or a combination of all.
I will take all this under advise from Repo

[repo]

Wayne, backpressure and surge issues are separate, although they both held us back.

[Audi_CQ]

is there a way to port the head to increase spool rather than delay it?

How could porting delay spool

[A80Avant]

bigger ports=less speed of the incoming air.

however, if head is ported,can the surge of a small ar turbo be reduced?

[JP]

Car drives well boosts quickly, but will have to resolve this problem with the surge, I will Look at the cams as suggested, I have not had a chance to measure exhaust back pressure yet, other options are possibly a bigger hot side or a combination of all.
I will take all this under advise from Repo

I've attached temporary plot until fuel pump issue is sorted (you can see the dip where it has a lean spike) and .82 housing fitted. For the road the .63 is lovely but on the racetrack and quarter the EGT's are borderline, so I'm using the cam timing to compensate for the larger backhousing. And then will be using the larger backhousing to allow for more top end power though ignition timing.

Note the redline is the stock cam configuration, very smooth power delivery but no real kick or wheelspin. The black line is advancing the intake cam in relation to the exhaust cam, leaving the exhaust cam relationship to the crank stock. Still no surge but much improved torque and hp delivery as much as 100hp gained at 4000rpm. Still smooth delivery but more relentless.

We also noted that irrespective of quite a radical change in cam degrees the top end power remained near enough identical indicating that we are either on the maximum the .63 housing can do or potentially the compressor is going too far of it's efficiency island. (obviously ignore the difference in whp as this is down to the change of tires).

Repo will have a better idea as to how the GT30R compares to your turbo but it should give you an indication of what the .63 housing can do when pushed.

[Jamo]

How could porting delay spool

http://www.s2forum.com/forum/showthread.php?t=21320

[EspenW]

Note the redline is the stock cam configuration, very smooth power delivery but no real kick or wheelspin. The black line is advancing the intake cam in relation to the exhaust cam, leaving the exhaust cam relationship to the crank stock. Still no surge but much improved torque and hp delivery as much as 100hp gained at 4000rpm. Still smooth delivery but more relentless.

Black one seems pretty steep, must kick pretty good betweem 3.5 and 4K.
Seems like you have a misfire or ignition pull between 4.5 and 5K?

[JP]

Seems like you have a misfire or ignition pull between 4.5 and 5K?

Ignition pull from a lean spike. Discovered only getting 12.3v at the fuel pump instead of 14+ v as measured at the alternator/battery. So fitting a relay this weekend, Mihnea who was mapping it says he sees it quite frequently on old cars and a fresh wiring feed direct to the battery has always solved the problem.

[Audi_CQ]

bigger ports=less speed of the incoming air.

however, if head is ported,can the surge of a small ar turbo be reduced?

Bad/wrong porting can of course make things worse, but a good porting job will make engine spool faster. Intake ports do not need much enlarging on a I5 20V head and with more air entering because of smooth ports and better valves, speed of incoming air will be about the same. This will create more power=more exhaust=better spool.
Better exhaust ports will get more of the energy to the turbo and spool will be better.

Porting the inlet side will help the engine take inn more air for a given boost so yes: porting can reduce surge. Better flowing valves with a good valve seat is also importent. More flow can often be gained with the right valve/seat then with the rest of the porting job.

Jamo: Can't see any proof there that porting kills spool?