ITS Ford Mustang(s) Build - Stripper Stang Part II

[Ron Earp]

And on the technical side, work continues at Stangwerks. We’re putting together motor number four, the second motor for the green car. The green car’s engine is still running well but the build is not of the quality of the engine in the red car. Len Hoffman from www.hamheads.com is doing the flow work and head prep for this new engine, while the block prep was done by a local machine shop. There will be a number of differences between this motor and what is in the green car: max 9.5:1 compression, good head work, torque plate bored, piston clearances, aftermarket OEM pistons (required, Ford doesn’t supply a 0.040” over), better ring package, carefully selected rods, different strategy for setting up the pushrods/lifters, and a few other changes.



We hope that this engine will perform better than the one in Sleestak. The red car’s engine is doing very well, although we are not generating any more top end speed at VIR. The mid-range we have is fantastic and we are probably in the upper percentile for off-corner power. But at the end of VIR’s back straight we won’t be doing much more than 123-125mph. I suspect the frontal area and Cd is just something we can’t get around. We are contemplating one more rear gear swap and avoiding fifth entirely because we can clearly see that when we have to use fifth the game is over, but that would cause us to have to use second in a couple of places on track and containing wheel spin with the high torque multiplication of second is going to be an issue. Anyhow, for the time being I think we’re going to struggle a bit on tracks that require a high top speed – VIR and CMS come to mind, we got nothing for the Acura and TR8 unless we manage to make some time in the short bits.



Lately we’ve been having a lot of problems with the red car and communicating with the ECU. We think we have it figured out, but in doing so we created a test rig for the bench where we can hook up an ECU outside of the car and program it. Dr. Giordano was the major motivation behind this job but it’ll definitely help us out for the future. We’re planning to mount it on a panel with switches, not this rigged up mess here, so that all you need to do is connect it to 12V, connect the laptop, and you can do whatever you want with the ECU. Programming the ECU in the car is what we generally do but this will help us prepare spares and test stuff out. We’re also planning to equip the ECU with an external EPROM so that we can load five pre-defined tunes into the ECU and switch them with a rotary switch, no laptop or reprogramming needed. The ECU program we’ve developed fuels very well but every now and then it needs a tweak. If we had four tunes with air fuel and timing targets, like 12.4, 12.8, 13.1, 13.3 we could quickly adjust up what was needed based on visual info off the wideband.



Work on DR COOL is progressing too. DR COOL is getting a dual peltier device engine, better insulation on all lines, a much better R value water reservoir, and an overall much lighter package even in comparison to the traditional water/ice cooling system. The goal is to have DR COOL in the car and functioning for the April RRR race.

[Ron Earp]

And we did a bit of clean up in the Mustang parts warehouse. I think we have enough parts above my garage to build another Mustang.





Took some different head castings apart for exploration. There are a good number of heads to work with on these cars, although the differences among them seem to be minor. Len has the "best" heads from what we can tell.



The number of blocks Ford has used, now that is a pain in the ass. We have discovered at least three different types of blocks for 94-98 MYs. No advantages among them that we can tell, but you've got to keep them separated because their critical bolts are not interchangable. We have sorted them into:

A - large coarse man cap bolts, short head bolts

B - small fine main cap bolts, one row short head bolts, one row long

C - smal fine main cap bolts with provisions for windage tray, long head bolts on both rows

We prefer "C", but it appears we've only got a pile of As and Bs, with both new motors having to be built from As.

And we got the Torino fired up and ready for the street.



However, the Torino could not hit the street. We worked with a local Ford guy in Mebane NC to have this motor built. But, he went too racy on the cam and what we've got is a big block Ford with all forged internals that wants to rev to 7k+ but won't idle worth a damn. We worked with the carb for 3-4 hours on adjustments to try and get it to idle but at 2k, running smoothly and purring along, it only generates 14" of vacuum. When the RPM hits 1500 that drops to 10", and as soon as we try and go lower the vacuum becomes non-existent and she won't run. Timing, fuel, idle, it seems that nothing will do the trick. But holy hell, rev this thing up and it sounds flat out awesome, like a NASCAR screamer. Anyhow, new cam and intake manifold on the way that is reported from a BB Ford builder and guru to cure this issue.

+------------------------------+

I've had a couple of people comment to me on the huge amount of time put into these cars and the relatively rapid development. No doubt, we spend a lot of time on the cars but having two cars being built at once provides more that twice the amount of development data. And it is less than twice the work. In looking back over the last 16 months we have disassembled three SN95 cars for parts, taken apart seven 3.8L Ford V6s of various years, built four race motors, built five rear ends with four different ratios, tried two different traction devices, tried out three types of brake pads, developed 20+ ECU tunes, dyno tuned at least five times, rebuilt two transmissions, run multiplr track widths, changed out springs rates four times and always going up in rate, Lots of changes in camber/caster/toe/corner weighting and had three separate exhaust systems built plus a lot of other things that I can't remember. For a single car/single driver team, in particular an oddball, this might normally take much, much more time. All I know is you're never at the end of development for an IT car although we're looking for the pace to slow down a bit.

But not yet. I'm out to Henderson at the crack of dawn to get a 2001 dual port 3.8L V6 as used in the ITR cars. Got an idea.....

[Ron]

Ron keep up the work. My parts area looks like yours. I have rows and rows of tried and failed parts. And the different motors, the 2.3 is just as bad. We have 3 race motors in development all the time and every block is different from ford. No real difference in "power" just little things that make them all their own.

I have had to take some time off from the car. Kids in college demand a ton of $$$$$$$$. I mean metric tons of $$$$$$$$. But we will be back, maybe with a different car powered by the same motor.

I am very lucky that I have great friends who have offered rides in their cars while mine is dormant. Wonderful friends.

[Andy Bettencourt]

Best build thread on IT.com

[Ron Earp]

Best build thread on IT.com

Thanks, we're trying to keep the fans happy.

Ron keep up the work. My parts area looks like yours. I have rows and rows of tried and failed parts. And the different motors, the 2.3 is just as bad.

Man, Ford is bad with parts. I just was reading through some of my info last night and Ford had used, up to 2001, ten different blocks for the 3.8. The variations are slight and mean little (other than the FWD/RWD distinction) but can create headaches for building engines and using parts on hand.

The 1999+ split port 3.8L engine is one hell of a motor. We got one yesterday and disassembled it to have a look at what it is all about. Mostly it is the same as the 3.8L single port motors like we have, but the heads on this engine can really breathe. They have two intake ports and larger valves to boot. The exhaust ports are tiny, but, they are way undersized for the gasket and unless the water jacket is a problem they could be improved even under IT rules. The motors are internally balanced therefore the crank is different than our engines.

Anyhow, for ITR I think these motors could really put down some power. They are rated at 190hp from the factory but they would see significant gains with a proper IT build. However, my main reason to purchase it didn't pan out so well. I wanted the windage tray from this engine since the 94-99 units are NLA from Ford and we're out of them. But, this motor is a 2001 and Ford decided to change the windage tray unit to be a stud girdle/windage tray that I can't use. At least the front cover was the same though and I can use that. Front covers are fragile and we've a pile of cracked ones.

Ron come to one of the race weekends and you can have a drive of the Mustang on a test day or race. I think you'd find it to be like your ITB car, just with a little more power. After all the underpinnings are essentially the same, very honest handling and fun to drive.

[Ron Earp]

Thanks but I'm sure lots of folks do some of this stuff, it's just people don't post about it. The vibrational analysis is Jeff G's forte. He's an engineer for a large company and that's his daily job, and, his Ph.D. is in vibrational analysis as well. Of course, that makes him extremely sensitive to vibrations but he's not been wrong about that aspect of the development.

Buried back up in the thread is the fact that the red car has a very odd, and sometimes extremely strong, vibration at certain RPMs. The green car does not have this problem, although it has a little vibration but not nearly the magnitude of the red car. We've done many experiments to rid ourselves of the problem: we've changed motor mounts, subframes, transmission mounts, two motors, one motor with a different balance percentage, transmissions, driveshafts, flywheel, pressure plate, pinon angle, u joints, axle shafts, tri-link, and axle housings. Still, the problem persists and the red car has broken three tailshaft housings while the green car has broken none.

We think we have a handle on it now though. We knew from Ford engineering papers that the 3.8 has a primary pitching moment fore-aft. With the measurements we think the moment can be particularly strong and believe the tailshaft became the weak link when the bellhousing would tag the chassis (clearance is extremely tight on the 3.8, about a pinky width at tightest point). So we're resolving some solutions to the problem and the green car will get them for good measure.
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EDIT:
For what it is worth, we now have a third Mustang build on the go and it's detailed on another forum. The car will be built to be IT-legal, but its primary, at least initially, purpose is LeChump so we decided not to build it here. That build thread will be more detailed than this thread since we're building even more items from scratch - panhard, trilink, perches, etc. will all be fabricated from steel by us to keep costs extremely low. On these stangs we paid over $1200 for a rear end setup we ended up only using half of, but with the new build we're spent $16 on steel to make the entire rear suspension, although with many more hours of work. Here is a link to the photo album with build pictures, although for narrative you'll have to go to the other forum.

https://www.facebook.com/Ron.Earp/me...4789574&type=3

[Steve35]

EDIT:
For what it is worth, we now have a third Mustang build on the go and it's detailed on another forum. The car will be built to be IT-legal, but its primary, at least initially, purpose is LeChump so we decided not to build it here. That build thread will be more detailed than this thread since we're building even more items from scratch - panhard, trilink, perches, etc. will all be fabricated from steel by us to keep costs extremely low. On these stangs we paid over $1200 for a rear end setup we ended up only using half of, but with the new build we're spent $16 on steel to make the entire rear suspension, although with many more hours of work. Here is a link to the photo album with build pictures, although for narrative you'll have to go to the other forum


What is the "other forum"

Steve

[Ron Earp]

Best build thread on IT.com

Thanks, we're trying to keep the fans happy.

Ron keep up the work. My parts area looks like yours. I have rows and rows of tried and failed parts. And the different motors, the 2.3 is just as bad.

Man, Ford is bad with parts. I just was reading through some of my info last night and Ford had used, up to 2001, ten different blocks for the 3.8. The variations are slight and mean little (other than the FWD/RWD distinction) but can create headaches for building engines and using parts on hand.

The 1999+ split port 3.8L engine is one hell of a motor. We got one yesterday and disassembled it to have a look at what it is all about. Mostly it is the same as the 3.8L single port motors like we have, but the heads on this engine can really breathe. They have two intake ports and larger valves to boot. The exhaust ports are tiny, but, they are way undersized for the gasket and unless the water jacket is a problem they could be improved even under IT rules. The motors are internally balanced therefore the crank is different than our engines.





Six intake ports, three cylinders. We're going to keep the parts around for the possibility of building an ITE motor for the stang we have, or maybe one day building an ITR car. Anyhow, for ITR I think these motors could really put down some power. They are rated at 190hp from the factory but they would see significant gains with a proper IT build. However, my main reason to purchase it didn't pan out so well. I wanted the windage tray from this engine since the 94-99 units are NLA from Ford and we're out of them. But, this motor is a 2001 and Ford decided to change the windage tray unit to be a stud girdle/windage tray that I can't use. At least the front cover was the same though and I can use that. Front covers are fragile and we've a pile of cracked ones.

Ron come to one of the race weekends and you can have a drive of the Mustang on a test day or race. I think you'd find it to be like your ITB car, just with a little more power. After all the underpinnings are essentially the same, very honest handling and fun to drive.

[Ron]

Thank you for the generous offer. I'm so glad that the car is a good handling beast. I'm sure it still is not light and nimble but perdictable and forgiving. Find the tracks that suit it best and you will continue with your success.

What I enjoy best about your build and development is that you and the team is that you are attacking several issues at the same time. None of this "lets improve braking first" "then fix handling" "Power now". You guys are hitting almost all of it all the time.

I, any many other non-traditional car developers, appreciate the effort in time and money it takes to make a car that doesn't come with a play book become competitive.

Well done boys, well done.

[lateapex911]

Good update, and great thorough work! Andy is right, best build thread here.

[Ron Earp]

Uh...it's like Fight Club I'm told. I can't link there.

Header piccy. We had the header off the other day for measurements so figure a picture would be worth putting up. Stainless steel, SS collectors as well, all properly sized. Version 3.0 but it was worth it for the midrange and top end gains.

[Ron Earp]

And gotta bust it up into multiple posts due to limit on pics. Anyhow, Jeff is still analyzing the data and looking for resonance effects from various vibrational modes.

[adamjabaay]

these have to be the two most developed cars in IT history. Truely inspiring, and intimidating, stuff ron and jeff.


unbelievable


what sort of go-faster-ness data come from the vibrational analysis.... Your way over my head!

[Ron Earp]

And more vibration analysis has been happening. This is from last weekend and fitting the chassis with three sensors as well as an RPM pickup to monitor the chassis, engine, and tranny throughout the RPM range.

[Ron Earp]

Been a long while since any updates but development has been continuing heavily over in the Stangwerks. Back in the May time frame we spent a lot of time at the dyno over two separate sessions. What we were trying to do was get the MAF transfer function to precisely fuel the car over the entire RPM range and pick up gains from our new exhausts. With A/F close doesn’t cut it because we do see differences when we’re off by 0.2 A/F ratio, and obviously as the difference becomes greater the power variation is higher.

Here is a plot from logged data in pulls through a couple of gears. As you can see the A/F drops a few tenths of a point over the RPM band. As the mixture gets richer the power tends to drop off and we end up with holes in the power band.



Here’s a close up example of what I’m refering to, with an original and corrected power curve in a fairly narrow 800 RPM wide window. In this particular section of the curve, down in the 4k region, the original pull was deficient about four horsepower in this section. And, this wasn’t the only area of the curve affected as there were a few other areas that needed attention. When we can get the engine to run consistently at the target A/F of around 12.9 it is noticably sharper and pulls with more authority throughout the RPM band.



The way we fix it is by re-mapping the MAF transfer function and shifting the limited number of cells for the curve to the RPM range of interest. As develiered the Ford ECU has most of the resolution of the curve focused in the 0-2500 RPM range and have very few points above that RPM. Furthermore, the Ford ECU V has adaptive learning so it starts to correct these values in the trasnfer function so that the operable RPM range becomes extremely well behaved.However, our operation is entirely different. We are only interested in WOT and the adaptive learning doesn’t not function at WOT, and, we don’t care about low RPM operation. What we do is use more cells/points in the 3000-5500 RPM range, thus allowing higher resolution there and more accuracy for delivered fuel.



The ECU can still apply modifiers based on intake air temperature, coolant temperature, load, and a few other things that affect the ultimate fueling. And we’ve learned the hard way that these modifier tables themselves need doctoring because they can be too intrusive to the detriment of power, however, they can be completely shut off. Anyhow, the end result of the work was that we had two independent MAF transfer functions, one for each engine, that performed far better than what we had at the outset. At CMP and RA we had dead nuts accurate fueling that resulted in more horsepower area under the curve.

We still haven’t had time to get one of the cars down to the chassis tuning dyno but I hope we have time in September. Our new trilink in the rear is behaving wonderfully and we’d really like to see some hard numbers, measured instead of calculated, to go along with our efforts.