I realize there isn't an exact relationship between MAF Grams and HP (variable like AFR, VE etc will alter it).

BUT,.. I was wondering if people that have dyno'd their cars could put up their wheel hp and their MAF Grams so we could get a little list going.

May be a second way to gauge hp besides 60-130 pulls.

HP, MAF Grams, AFR, dyno brand


After Sambo tuned my 997.1TT recently,.. I did a 3rd gear pull this morning and recorded 504.54 grams per side at 6,920 rpm, on 93 oct + meth, with an average AFR of 11.4

Anyone have a guess what that is at the wheels? At the crank?

I know it's just bragging rights,.. which is silly. When people ask me what it's making,.. I say I don't know,.. but the key is in it, and they can try it out for themselves. But when a good friend across the country asks how it's going with the car,...well,.. I wish I had some sort of answer.

 

Hey my friend!

Oh boy my buddy Maestro is gonna bust this door down and place a bet haha!

It's is based on a few things but I think you are at about 650+ so you are not far off on that guess. With more meth you will feel it and that will put you damn close to 700 based on the set up and mapping.

 

I did just turn it up from 1.25 to 1.5

I'm spraying 75% / 25% now, through two 1.0mm jets.

And with the scaler set at 1.5 x the IDC,.. ithe Aquamist HSF-3 system is really close to 100% duty cycle (in theory at least).

There is a gain adjustment though. It lets the system ramp up and down with IDC until a certain point,.. and then taper off or gain more. I have it tapering off a bit. So I could dial that up a touch and try again.

Or should I just go for 1.1 mm nozzles?

So unless I put in bigger jets,.... that's all she wrote.

M3Maestro knows his stuff. We PM'd back and fourth a few times before I decided on turbos (now 63.5 VTG's). I'd LOVE to hear him weigh in, even if it is to tear the place up. LOL

Never stop learning.

 

Ah yes MAF numbers! Nothing brightens up a turbo engineer's day more than seeing huge airflow numbers .

So yes HP will vary at the same airflow but you can correlate it if you have all the inputs. For example my car on 93oct and E85 runs the same airflow (~500g/s), yet there is roughly 80-100hp difference cause of timing, BSFC etc.

To keep it simple, 500g/s @7krpm is right on for a 63.5mm vtg car. You might want to give virtual dyno a try, I have mentioned it a few times on forum and others have started using it now. We have even seen it compare well against real dynos. The key is good data and correct inputs. I can help you with those if you try it out. Without seeing any of your data I'm guessing you are around 630-670whp range. I know its a big range but I have no idea how the car is tuned.

I have recently seen some data from the 68mm Sam has installed on a few cars and they look real good. You will give up a tiny bit of response which is expected but good gain in power. At 7krpm those are in the mid 500s if I recall (540-550g/s). I think on the built 997.1 engine car they ran them up to 580-590 g/s at 7.8krpm?? Sam can confirm.

From the data I have collected and the data I got from Bosch, I'm estimating 600g/s will cap out the meters. However that's not taking into account part to part variation, accuracy, etc etc. Also going up that high the curve is real steep...the measurement the sensor is giving you isn't that good in that region to be honest. Just cause it could read that high it doesn't mean it should be used there.

Hope you are enjoying the 63.5mm, they are a nice street turbo for sure. However with winter coming and the car will be just sitting there...those 68mm are tempting

 

Nope,.. no temptation to go up on the turbos.

Really don't want to build the engine,.. and I'm having traction issues as it is.

This winter's project is a Porsche Cup LSD.

Then I think I'm done. LOL

 

I'm the one who is tempted

 

Cheers guys. Maestro I'm going to do my best to keep you under control because I know what's going on in that mind of yours! One day I'm going to do one turbo charger on each side of a car and see if you catch it LOL!

Stuart your car looks really good. It's moving along and there's a lot of timing and her. I bet you if you touch up that adjustment a little bit you're going to be pretty good. If not we could bump the Jets up a notch. But I think if it gets a little more of the drink you'll feel it. On the next logs I'll show you how to come up with injector duty cycle so you can have it right there for yourself. You also want to check consistency and not load Spike. It would be nice if there was some headroom in the system though.

 

Yep. Never ever.

Just curious,.. what does it cost to have rods put in one of these?



Sam,. the methanol "system" has more capacity,.. just not duty-cycle on the high-speed valve (an in-line injector of sorts).

Being as I'm near 100% duty cycle on that,.. the next step it to jet up.

I'll check the gain adjustment and see if there's a bit left in it. Otherwise I'll have Richard mail me some 1.1's.

 

oh wait wait wait you just said no bigger turbos you are done etc. Now you are talking rods ROFL Look isn't admitting the problem the first stage of recovery? I knew after I got use to the 63.5mm I would want more...you always do.