386 RWHP @ 13PSI, Turbo-NA w/GT4088R, Aux Bridge, etc.
 

This is basically a copy and paste from my buildup thread with the addition of the dyno sheet.

On Monday I booked some time at Chandler Techologies to run the car on their Dynocom dyno. I was initially worried that the day was not going to go so well as my passenger side front caliper stuck on the way there (what the hell? Seriously....) but then again, you don't need front brakes to dyno a car!

After the car was strapped in, the baseline run made 320 RWHP at 13 PSI. Much more then was expected (I guessed it would make 266, others guessed 275) keeping in mind that the current "tune" in boost just meant that the A/F ratios were barely registering on the gauge at something other then 10:1 flat.

With each successive run we pulled a bit of fuel and gained between 10 and 20 HP every time. After approximately 6-8 runs (I lost count) the final number was 387 RWHP, 279 FT-LBS @ 13 PSI. A conservative estimate puts that right around 420 HP at the flywheel. Not half bad for an hour on the dyno on low boost. A/F ratios are in the mid 12s until about 5 PSI, falling to the mid 11s to 10 PSI, then low 11s to 13 PSI. Timing is still VERY conservative at 10 degrees. I could put a few degrees of timing into it right now and pick up a few more HP but I'd rather wait and borrow an EGT gauge (or buy a cheap one) before I start bumping timing too much.

The video from the last few runs is available to download in two formats. The first is a high quality Windows Media file and is about 15 MB in size. You can really see and hear things the way it took place (the whine from the turbo is unbelievable). You'll probably want to "Right Click, Save As" to download it instead of opening it directly in your media player. The 2nd link is the same video on YouTube but the quality is not that great (especially the audio).

Project Tina First Dyno Runs (WMV High Quality)

Project Tina First Dyno Runs On YouTube

The next step is to install a boost controller and crank that turbo up to 17 PSI where it belongs. I fully expect 500 HP to the wheels once I get into real boost...

If you look at the dyno sheet, the torque curve is very intersting. Quite flat once the turbo has reached full boost. My only annoyance is that the wastegate seems to be stating to open around 8 PSI which is introducing some lag. This will be fixed with a boost controller.

Your car sounds so sweet!! Nice Job!!!!

Wow, really impressive. The long, detailed build has finally paid you back in excellent power... You deserve it. :)

Cool vid. I know you're planning on uping the boost, but even now, what are your driving impressions? Are you glad you went big turbo? Just curious. :D

that is insane. I'm sure you've been asked, but how much boost do you plan to run after it's tuned. I'm assuming you'll tune w/ pump gas? I can't imagine how much c16 must cost up there.

Impressions of the car...well, it's terrifying. :) Because I'm still using an open diff (the stock diff that came with the car) there is a lot of drama at anything more then 50% throttle. Tires squealing, smoke, rear end stepping out, etc. But once the car gets traction it pulls like there's not tomorrow. Forget trying to look at the tach during 1st and 2nd gear. By the time you've kept the car straight and have some time to look down at the tach you're already at 8K. Generally the 1st and 2nd gears need to be driven using the overrev buzzer.

There is some lag in this setup, but mainly that seems to be a wastegate issue. It is opening up quite early (as expected...a 13 PSI spring isn't an on/off switch that goes from full close to full open at 13 PSI). A boost controller and lower pressure spring will clear that.

I need a LSD of some kind. There are several options for the NA diff.

Drivability is really issue free. There's a few times in traffic where I can catch the idle while letting out the clutch so the car will "pig root" a little, but aside from that it starts and drives as if it was stock.

I'm happy with 13 PSI right now and there's not much point in increasing it until I can fix the diff. But I plan to run around 17-18 PSI for around 500 RWHP. With conservative timing I don't expect any problems with pump gas.

Running anything but pump gas it simply not an option since this car is a driver. I take it to work, haul stuff in it, etc.

He says right in the inital post he is going for 17psi....

BTW very nice work....

Are you planning to stay with the 7" rear diff?

It will be interesting to see how that holds up if you are. I would imangine you have already answered this question in some detail somewhere else.....(probabl more than once)...

One more question, does that specific Dyno have the ability to sense clutch slip? (reads spark plug wire for engine RPM like a timing light does)

I would worry about that, if you are running an NA transmission especially.

Even if the clutch will hold to break the tires loose in the first 3 gears on the street a Dyno can make it slip pretty easily.

makes no sense to decrease the spring if your going to increase boost
a electric boost controller has a gain feature use that to adjust response

On the good ones the setting is called "Gate Pressure Point"

You can actually set at what boost you want the wastegate to start opening...

But, if not careful you can program in your own little low RPM boost spike... ;)

I want to also have a "very" low boost setting for use in the rain or when traction could be an issue. Hence the lower PSI spring.

In reply to your earlier post, I'm not too worried about the differential right now as far as strength goes. The NA diffs have been shown to take a lot of abuse from things like V8 conversions and they rarely seem to break. The TII unit is of course stronger but I'm fairly against having any TII parts on this car. If I have diff issues, I'll rebuild it with an aftermarket center section and have the gears treated appropriately.

I have not seen any indications of clutch slippage either on the dyno or on the street. The copper 6 puck seems to be holding up just fine.

As for the NA transmission, I'm not worried really. It's already been abused a lot this year and seems to be as happy as ever.

I figure if it's not slipping in 5th gear under full boost, it's not going to slip on the dyno in 3rd either. :)

The difference of course is they strap the car down and sometimes unrealistically load the car to ensure a safe tune under all conditions. So they can load the car up even more than it would be with two people under full boost in 5th gear in a head wind. This is where my tuner sees cars clutches slip a lot. It is nearly impossible to percieve this especially with good clutches. There is no indication in the drivers seat that it is happening but good dynos have the capability to detect it by monitoring RPM signal. Less experienced tuners end up actually miss tuning engines this way.

They say it happens with those silly guys that turbo thier hondas and still have these dinky little clutches. Even with a "good" clutch and no slip on the street it can happen on the dyno. But it can also happen inperceptibly on the street too...

:lol:

I don't know what to tell you. :) Having the clutch slip is one of most minor concerns that I have regarding this car. The fabricated copper 6 puck (sprung of course) that is used in this car is something that has been used in a lot of RX-7s (and some nasty Supras) locally and it seems to hold up quite well. Could it be slipping? Maybe. Is it noticeable at all? Nope. :) The tach vs. speedometer on the dyno was completely linear so if it did slip, it wasn't much....

Why this concern about the clutch?

I think they were a little wussy on the dyno brake, to be honest. Next time I'll have to make sure to get them to really load the car because there was a noticeable lag in boost.

I'm not sure what that means. Are you saying I'm wrong? Or right? Because there are a lot of 11 second cars running the NA diff...

congrats Aaron keep on proving em wrong!!!! :icon_tup: NA turbo power!!!

the N/A units that do NOT break are the open diff units, because they can let one wheel spin and release the torque that would rip an LSD apart (stub shafts FTL).
you really need a TII clutchpack all freshly rebuilt in there if you plan on doing any hard launches.

good luck on the project man it sounds like an animal! WOOOHOOO!
rock on!
more pics!
:)

I think you will probably find out quickly enough, and it was just a thought for discussion. I was not predicting anytihng. I would guess a good clutch setup even in the N/A transmission is going to hold quite a bit of power.....

ive been told that the higher compression N/A rotors dont mesh good with high psi and that if you plan on going above 8ish psi you really risk alot of knocking, is this true? thanx.

Wow, that's very impressive...great work!

That makes sense, and is kind of where I'm at right now. First one wheel lets go, then they both do. :) Makes for some fun driving, but slow E/Ts in the 1/4. I'm quite against having TII parts on this car so what I will likely end up with is an aftermarket center section and then a set of shafts made by the local driveline company.

More pics?! There's already more then 500 out there! :)

The transmission seems to he holding up like a champ. No noise or slop has developed and obviously it's not failed catastrophically. When I start getting more rear traction there may be some issues but then again, I've never broken an NA transmission due to power (only due to wear and lack of oil).

Not true. Like anything else, if it is tuned poorly, there will be problems.

nice job. sprung 6 puck FTW!

Nice torque curve

I'm curious as to why you didn't dyno it from idle... just to see how it reacts from going to full vacuum to full boost.

Showing the torque curve from 3K and up just seems like cheating.

is it true!>?!>?
what do you think his car is :shocking: