Saga continues....

I converted my TII motor back to FI with a Microtech LT-8 and took her down to the Dyno for re-tuning. After some time and 5 Dyno pulls, my BITCH pulled 439 HP at 13Lbs of boost. After a few minutes of contemplating what we were going to do, my tuner and I decided we would give it one more pull to try and be at an even 450HP....

Well she didn't agree with us and now I have a cracked front plate. I have already pulled the motor apart and sourced a new front plate. I will be pinning the motor this go around and will hope to get closer to 500 HP. I will update everyone once it is running again..

L8R

 

'85 Rx7 Limited

13b bridgeport
Turbonetics T76
Tial 44mm
880/1700cc inj

430hp atw 18psi

Cracked apex seal due to poor maintenance from previous rebuild.

New motor just built and running in, will post up new figures when tuned.

 

http://www.youtube.com/watch?v=g6wwr773Uek

170whp four times in a row with no cooldown period or fan in front of the car. Coolant temp never went over 180-ish.

I'm happy Can't find the dyno plot but the peak power wasn't very high up - 7000-7200rpm.

S4 N/A rotating assembly, rotors lightly skimmed by hand for clearance and bearings LIGHTLY polished

OEM everything seals except new-ish oil control O-rings, FD corner seal springs, Atkins cryogenically treated apex seals clearanced to Judge Ito specs.

~100psi oil pressure... at idle. My first 13B build and I'm really paranoid about the rotors hitting the side housings at high RPM.

S4 13BT housings, big-ish street ports (the trailing edges of the side seals BARELY fall in, so there's lots room to go bigger) and decent sized exhaust ports (again, more room for more port).

Harbor Freight O-rings for the dowel pins and front cover, Right Stuff and 18 gauge wire (yellow for speed!) for coolant seals. I can assemble two engines for less than the cost of one Mazda coolant seal.

S4 T2 intake manifold that has had all the weird bumps and ***** removed from the lower. Needed lots JB Weld to fill in the ACV passage since you will hit air if you do this. S4 N/A throttle body flipped upside down, Autozone cone filter stuck directly on intake elbow.

Aluminum flywheel from... someone. Came with the N/A core engine. Really light. It's red. Can't tell much of a difference from a stock flywheel.

MSD 6AL driving both leading and trailing coils through distributor. Locked timing. So that's 27 degrees, leading and trailing, all the time. I haven't played with timing yet, it seems like it might like less but I don't want to take any out until I have a way of adding it back under cruise.

Megasquirt 1.01 driving 2x680cc injectors. The injectors don't *quite* go static but they are at 85% at 7000rpm. Will be 4x480 when I change the exhaust.

Mind-Train 12A header ovalled/ported to fit on a 13B. Hacked and slicked and re-hacked and re-sliced 2 1/4" converter, stock 12A midpipe, unknown muffler, possibly Mind-Train, definitely a chamber style muffler since it looks kind of like a dumpling right now after all the BANG BANG BANG. Will be 2 1/2" with three straight-through mufflers Some Day Now, Really, I Mean It, I Just Don't Have the Time. (It makes more power than I can use. Why mess with it?)

 

Is anyone updating the graph anymore??

 

Just a little update...
Got home from the Dyno about 30 mins ago and we left all as is. I am encountering ALOTT of wheel spin and it made no sense to up the boost. My tuner decided that it would be smart to make her a bit more durable versus making higher numbers and not being able to get it to the ground.
I have someone that made me an offer on her so I may be selling her soon so time will tell...
Here is a very short vid a friend of mine took with his cell phone. I took the camara but the %$@& battery was dead.....



L8R

 

12a stock port (~100000 miles on it)
RB Dellorto carb and intake
RE street exhaust
2GDFIS
Electric fan (dual from a MR2 MKI)
Resurfaced 82 flywheel
Centerforce stage 2 clutch/pressure plate

I have to say I don't think I can get much more out of this 12a unless I crack the keg.
Very pleased with the results.

 

I think you can do better, looks like something is really restricting the top end there. Your torque curve should be alot flatter if you've maxed out the engine. Whats your AFR? Also how big is your exhaust? and what size carbs do you have?

 

This is hp to the rear wheels, so add back in conservatively 12% drive train losses and your at
about 150 hp at the flywheel. I don't think you can get much more than that out of a stock port
12a. I may be able to squeeze 5 hp from it with more tuning and dyno time but I doubt it.

I think the torque curve is shifted over mostly due to the long intake runners of the RB intake
that came with the carb. That curve would probably shift over and flatten a bit with a shorter
intake like a lake cities or the australian weber intakes that are sold now. I don't have an AFR
guage setup or the bungs to put a sensor in, this is an old school car, we didn't have that stuff
back in the 80s

If you have some secret for getting more out without boost and without cracking the keg I'm all
ears. I have thought about a cold air box on the Dell but haven't bothered yet with that.

 

The scale makes it look more peaky than it really is.

 

Thanks I forgot all about that. Notice the torque and hp cross over at the magic 5200 mark pretty much exactly as Yaw describes it in one of his articles.

 

You can still get an AFR reading from hooking up a device to the back of the tailpipe, its not as accurate but still give you a good ball park.

You're intake is definatly not the restriction in this case. I have the same intake (assuming its the DCOE style racing beat has) and i'm making my peak torque at 7000 rpm, even on yaw went back to the S4 or s5 style manifold for the longer runners to bring the torque down, which is something that I'll be doing but making a custom intake manifold out of tubes.

What size carbs are you running? Could be your determining factor. I have 47mm ITBs, although a bit different but should yield around the same power whether its carbed or ITB. just how much you can play in the center is what the difference is mostly. But ya it could just be carb size too small.

 

I'm running the Dellorto 48 DHLA with I think it has 36 chokes in it. The carbs plenty big enough, in fact with rejetting it and a choke change it can run a SP or a bridge no problem.

Running ITBs with fuel injection is a whole other world. Not interested in running a stand alone or computer on this car. I'd like to keep it all analog.

So to the wheels, if you think I can get more, what number do you think I can get too? You keep saying I can do better but I have yet to hear any firm estimates of what your expectations would be.

Like I said I'm all ears for any analog ways to increase hp without a rebuild. Two areas that could use work are the air intake (make it colder) and the ignition (changing plugs and/or using an MSD) both of which I doubt will yield much more than maybe a few hp so they may not be worth it.

 

I'm not talking mostly about peak power, but overall power by smoothing out the torque curve a bit (~6-10 ft-lb in the 5000-6000rpm but also ~ 3-5 ft-lb by 7000rpm) so ya around 140whp at peak.

Like I said if you could go and get AFR reading that would be kinda key to look at to see if AFR could be improvised on. If you're floating in the mid to high 12's you're most likely loosing abit of power from being too rich. You're going want to be over 13.2 roughly (Every engine is going to be different, but thats always been a decent starting point for me, and then from there lean it out a tad in one run and richen up a bit in another and see how the graph is moving.

Another thing too is split timing. Alot of the EFI gas (just because thats what I mostly know), are running 0 or about zero split between the leading and trailing. Not sure if you can do that with the distributor or not, but the less split as you go up in the rpm the better normally (I've even seen a few cases run negative split). But me personally going from about 13 degrees split to 0 I definatly noticed the difference right away in acceleration, engine feels 100 times more alive and seems to pick up quite a bit more in the top end. I don't have dyno figures of that yet, but once I hit back the dyno I'm definatly doing a run with my old split map and my new one and see how much more it actually picked up.

On the same topic of ignition, play around with just timing itself can do quite a bit. When I had my holley we were playing around with the distributor timing and that can easily cost you about 10whp if not set right. Surprisingly, when I initially set mine up (just with the engine idling and slowly going up till I hear the engine fall back again, was the best setting. Also for reference I wasn't running any vaccum advance to it neither just so you know)

Lastly, having fresh fluids in engine, tranny, and rear end will be good for maybe 1-2 hp depending how old the stuff is in there, and lastly one that is sometimes overlooked is all the bearings in the rear end (diff bearing, and axle bearings)

Hope that helps in anyway

 

JDM 12A turbo, running NA
Extend port, race exhaust
Dowelled, studded and oil pan girdle
Haltech E6X
Electric water pump and power steering

Sheet below.

 

Now with boost..



Im to tired to get into details, so ill get to the specs later..

 

made 113whp and 106tq.
rb dual header, exhaust shop special center section, collected to 2 1/2". Stock intake/ carb with no emissions. primary fuel jets drilled to .055" and secondaries drilled to .076".

i'll see if i can scan it in a bit, but the tq and hp curve are for the most part flat

 

Definitely need to open up that intake. You can free up at least 20 ponies with a modded nikki (aka Sterling) or a big webber.

 

I've since installed a RB SP exhaust, the dual one to the over the axle pipe
with a much freer flowing muffler than the old RE setup I had. It feels like I
have more power. Now I just have to get back to a dyno sometime and see
if thats true. I had just put it on before we went to ZoomFest.

Your car looked awesome at ZoomFest BTW.

 

yup, i was also running a tad rich at 11.8 afr, and i have a side draft manifold, but need a carb. car spends most of its time between 5-8k rpm so not too worried about the lack of bottom end that i'll get with the weber

 

Drilling the secondaries to .076 killed you. Leave them stock (.063) & wire up your secondaries.

 

thats the thing, all the carbs i have measure out to .073 jets on the secondaries, so its not much of a difference. and as for the primaries, i had them measure out a .27 stock and i drilled them to .055 which is what you recommend on your site.

and it has mechanical secondaries by the way

 

All of what carbs have .073 secondary jets?
-Not stock jetted Nikkis.
The velocity going through the small Nikki secondary venturi provides a much greater signal to the main circuit than that of a Holley's secondary venturi. So the jetting that's good for a Holley has nothing to do with jetting for a Nikki.

 

well, ok, they are all stamped 180 secondaries and 60 primarys.
do the math it comes out to a .070 on the secondaries and .023 on the primaries

 

I put my car back on the dyno this past weekend and it made 484.9 RWHP and 367 RWTQ at 21 psi on a T67 turbo. It was also on a dyno that was known to read low. Maxed out the NPR intercooler...

 

Just for the record HP and Torque Curves will always cross at 5252 RPM. This is due to the mathamatical equation which translates torque (force applied in a circular motion through a lever) to HP (amount of work that can be completed in a given amount of time, in our case its relevant to revs per minute) dont quote me on the definitions but look them up if you want im just going off of memory.