Agree.

 

Bigger turbos do not necessarily mean faster 60 to 130s.. be careful trying to compare back to back. do not make that your benchmark... because sometimes guys will go backwards trying to go faster... if the car feels good thats all that counts...
good luck
markski

 

Thanks Markski. The car feels very strong in the range that I usually drive. I don't chase the numbers just for the sake of numbers, it's more for a benchmark to see if I'm fooling myself with the butt dyno, lol.

I did see your post in the other thread and will ask my tuner if the car is "dumping fuel" to keep itself safe in the higher rpms. I didn't think THAT was the issue, but it's certainly something to consider. My IATs have been very good but I'm not sure if that tells anything when it comes to turbos getting hot. Appreciate any comments. My goal is to have a SAFE car, not get the absolute last bit of performance from pumpgas.

 

A question about dyno tuning.....

This may seem like a silly question but Despite all the fans in place around the dyno i dont think the car is seeing as much air as would be out driving around doing pulls on the street. So if u lean out your fuel trims looking for that extra hp whilst dyno tuning, is there not a risk of leaning out too much when u out on the street where the car would presumably get more air?

 

That's not really how it works. There are two systems working together to make sure this doesn't happen.

First, on the way into the engine are the mass airflow sensors (MAFs) which are measuring the amount of air going into the engine. The amount of fuel injected is determined (in part) by the measurement of the MAF. Second, on the way out of the engine the wideband o2 sensors are being used by the ECU/DME to constantly monitor the air/fuel ratio. It is then trimming the overall amount of fuel being delivered in real time to compensate. This can be logged as short term fuel term (STFT) by the Cobb AP.

Really the only risk with the car not getting as much air as it would on the road is intercooler and/or radiator efficiency, which can raise engine temperature and intake air temp. You will generally see lower intake air temps on the street.

 

I'm running mafless, so the mafs aren't a part of the equation but the wideband sensors sure are.


As Rix said, the fans are for cooling air not combustion air.


dynotuning tells you things that the datalogs don't, and I would say the best thing is to do a combination of dynotuning and datalogging on the street.

 

Just a little update - things are going well with the fine tuning. Dzenno figured out that the torque limits had to be increased in the dme b/c these turbos can really push some air. Once that was done he sent me a more "aggressive" tune but we quickly ran out of injector! (stock injectors with 5 bar fpr). We had to tone it down a little and the current tune in low boost is super smooth and pulls strongly and steadily up to redline. The injector duty cycle is about 85% with this version leaving a little bit of a safety margin, but new injectors are in the cards...
We haven't gotten the sport mode tune done yet but I'm confident that it won't take long to dial in. Again, it can't be too aggressive otherwise we'll run out of injector!

 

You're out of injector with the stock injectors and 5 bar FPR on pump gas? I don't remember champion ever saying they upgrade the injectors, but I guess they did.

 

We do. Inevitably the choice of what injector to use is something you should discuss with the tuner, but I can tell you that we recommend at least a 750 injector and then put back the stock 3.5 bar FPR.

 

Ken has 72lb injectors on his 68vtg car with 3.8bar fpr.

I am considering ID1000s. I think they will probably be enough even if e85 becomes available. If not, I could always put the 5 bar fpr back on at that time!

 

68s can easily max out the OEM injectors even with the 5bar fpr. We now have a really great looking map on The Bogg's car. A few more tweaks we're trying to get the most out of his current fueling but its clear that upgraded injectors are a must at this point.

I wouldn't personally recommend anyone upgrade their fuel system with a 5bar fpr. Its a bandaid and it really should be done right with appropriately sized quality injectors leaving the OEM FPR in place. ID1000s fit that bill spot on with some room to spare. If you'll be running E85 on the car I'd even go a little bigger on the 68s to ID1300s but for gas ID1000s are plenty.

 

I am putting ID1300s on my car this weekend if all goes to plan .

 

Lucky you!


If I knew e85 was coming here anytime soon I'd consider ID1300s, but at half the price the ID1000 makes more sense since it offers enough for pump/race and probably "good enough" for e85 if and when it comes. The Proto 80lb(840cc) plus 5bar fpr were good enough for sub-6 60-130 on e85 with Champion 68s with 137mph et in 1/4. With ID1000s it would have a bit more headroom even if it wasn't maxing out the turbo.


Anyone figure out how many hours it takes a decent shop to change the injectors?


Right now the map above 5500 rpm is pretty much fuel limited (low 90s injector duty cycle) so we are just working on beefing up the 3.5-5.5k rpm range and it's done for stock injectors with 5 bar fpr.

 

The ID1000 are rated at 1000cc or so at 3 bar, is the injector pressure 3.8bar with stock fpr or is that fuel rail pressure or is it the same? lol. I was reading a bit about the different ways different cars regulate fuel pressure. Not sure how it's done in the 997tt but if anyone wants to explain please do!

 

I think somewhere around 4 hours with the engine in.