JRP944

The torch has been passed and @Tony5 is the new steward. Excited to see this on a slightly hot-rodded motor.

JRP

Tony5

So I'm just staring at my engine bay mentally preparing for ITB install.
Issues identified so far:
1) My early fuel rail with the S bend fuel in line probably won't jive with the plenum. I may try heating and bending the S shape to an L shape to run under the plenum, or use a spare fuel rail from a 1984 engine where the fuel in is at the rear of the rail.
2) If I remember correctly the AOS hole sizes are different from early to late cars, so I may not be able to utilize the AOS JRP944 is including, I may need to modify my current AOS.
3) My strut tower brace may not play nice with the plenum height. We'll cross that bridge if/when we get there. I would definitely like to keep the STB.

I've long since disposed of my AAV/IAC stuff and the only vacuum lines I have left are going to the brake booster and the FPR/FPD, so it should be a pretty simple install with almost no ancillaries in the way or in need of vacuum. Im pretty excited to get this setup up and running.
Future plans (distant future) for the engine relating to the ITB's and squeezing more power out are just to install the 944Store stage 3 head. The ports on that head are based on the 2.7L head and the ITB runners will need to be matched to it. CFM gains are substantial if you believe the graphs and the valvetrain is significantly lightened so I'm thinking this thing will end up singing pretty good up high.
Maybe a full standalone management system way down the line to really fine tune things, it couldn't hurt since with this purchase I'm putting all my chips on NA life and putting any thoughts of forced induction to bed.
No plans to open up the bottom end of the engine at this time to add stroke or compression, so this will end up being a near maxed out 2.5L NA as far as bolt ons can go.

JRP944

Sounds like you’ll be building what I ultimately dreamed of. Just ran out of steam before getting it all done. You will certainly have a unique engine when complete!

JRP

Tony5

Update inbound when I get some spare time. For now I'll just say these things are awesome.

Tony5

So 200 miles later, I've got some thoughts on these ITB's.

But we'll start from the beginning.
If anyone ever has the opportunity to deal with @JRP944 do so with confidence. Great communication, fast shipping and he packaged the kit up to be bombproof.
Upon first inspection, it's a work of art. It's exactly what I would've dreamt up myself, but brought to life better than I could have done. Attention to detail, finish and futureproofing are all top notch. Everything works smoothly, no binding, no rough spots. Everyone whose seen it in person so far immediately thought that it was a thoroughly engineered product being made by some name brand company for retail sale. Even the hose clamps he sent with are nice yellow zinc plated pieces.

Install was very straightforward. If I had a late car it probably would've taken me less than 1.5 hours. I had to cut down my early AOS and install the late AOS top cap on it for clearance. I have plugs in the two 1/4" NPT holes and a 90° elbow to 3/4" barbed hose fitting in the 3/8" NPT hole, I was able to spin my old AOS hose upside down, cut 2" off and reuse it. Single 1/2" hose to my brake booster, one small vacuum line to a T running my FPR/FPD. I had to heat up and re shape my S bend fuel in hardline that originally went over the plenum, I made it more of a hockey stick and ran it under. My throttle cable is too long for the cable stop to slot in to the throttle cam, so zip tie to the rescue till the new set screw cable stop arrives.
At this point the car started right up, idled great, revved easily. Then I smelled the gas. Loosening the stubborn S shaped fuel line cracked my fuel rail. It took two hours up to this point.
Day 2, I buy some longer fuel hose and install a spare fuel rail off of a 1984 car, where the fuel comes in at the rear of the rail. Again, car starts right up and runs great.

Maiden voyage, the exhaust immediately sounds different. Lower tone at low RPM's and some of the raspiness is gone. You can hear more intake noise and some whistling that sounds kinda vacuum leakish, but nothing drastic while I make my way to some open roads and let the car warm up.

Then I finally get to let it rip. Huge disappointment. It sounded cool, but i spent the next ten miles trying to decide how I was going to convince my friends that cool sounds were a good trade for massive power loss. By the time I got home I decided that the throttle wasn't getting to 100% open. It had to be that, because I couldn't accept that the car was so slow. I had one of my kids step on the go pedal while I watched underhood. Nope, it was going wide open. More disappointment. Then I noticed the gold paint on throttle linkage #1. And then the gold paint missing from the underside of my hood. So I closed the hood, pushed the pedal as far as it would go and popped the hood release. The pedal went probably another 30% further. What a relief.
This hood is scheduled to be replaced by an FG one when my paint guy finally gets caught up, so I had no qualms about cutting a chunk of the under hood bracing material out for clearance. Throttle feels like it's working now. Test drive 2# starts off well enough. Way more power when I have all the pedal travel. But I didn't cut out enough hood bracing and my throttle occasionally sticks at WOT. That's not a great experience in case you were wondering.
A little more clearancing, everything works now and day 2 comes to an end.

Day 3 and I can really start laying on some miles. The sound is great. The car is definitely louder, but not from the exhaust. The pedal feel takes some serious recalibration to get used to. It's stiffer, but not linear, it's also got quite a bit more travel. It gets stiff enough at 3/4 travel that between the stiffness and the increased travel, I often think I'm at WOT and I'm not even close. And that's important, because unlike with the standard manifold where 80% throttle seems to get you 95% of the ponies, it's now much more of a 1:1 ratio, if you have the pedal at 90%, adding the last 10% gives you noticeably more power. The one other person that's driven it so far thought I was being pedantic when I told him this. Then he ended up describing it the exact same way.
Speaking of power, I do believe there is more of it up top. There's also less torque down low. I'm fine with the trade, I only own this car for fun and I'm not sure if I've ever shifted below 4k rpm, so more fun up top is great.

But the sound is the real star of the show.
I'm gonna warn you up front, I've made multiple in car and drive by videos, and the in car ones are terrible. It doesnt do the ITB's any justice.
I thought the drive by videos did better but my cameraman said they were garbage. A day later I was able to be the cameraman, and yes, the videos I got on my phone do not capture half of what you hear in person.
Seriously, if someone with quality recording equipment in the northern IL or southern WI area wants to do right by the music the car makes, hit me up and we'll get some real footage.

I made a quick before/after video, and the difference is there but I feel like I need to delete it now after hearing it properly from outside the car.

VilleJKL

Tony5 are you running standard injection including the AFM? You probably know already, getting standalone management will gain you 20hp and get your midrange back. Nice sound, by the way, and the landscape ain't bad either. I wish we had empty roads like that to open the throttle.

JRP944

@Tony5 Great update! You really made quick work of the install and getting things sorted out. I'm super stoked that these are working out so well for you - much better than them sitting in my garage collecting dust. Can you share some pictures of the kit installed in your engine bay? I'm curious to see the intake plumbing since I know you're running the MAF.

I'd also love to see some other pictures of the whole car. It looked good in the drive-by!

JRP

Tony5

I'm currently running the Lindsey MAF. I'm happy enough with it for now, but I'm sure some day I'll get the itch to optimize further with a standalone system.
I was pleased with the sound till I heard it in person, the video is pretty disappointing after that.
And yeah, lots of empty roads out here in flyover country, that's just a random one a mile away that I made the old video on months ago. Figured I'd make the latest one there for continuity.

Tony5

I'll get some engine bay pics once it's all put back together. The newfound interest in high RPM's that my engine has motivated me to track down a high RPM misfire issue I've had for a couple months.
At 6k it acted like it had a rev limiter. A kinda soft one, like it was just on one cylinder and I could maybe get it to rev higher if I kept my foot in it.
I've been lazily checking various electrical, ignition, fuel and timing components for a few months and pretty much narrowed it down to something mechanical, I had my money on a broken valve spring. Took the cam housing off Sunday, lo and behold.

Kinda hard to see in the picture, but that's definitely a broken inner valve spring. With some luck I'll have it back together this Sunday and I'll get some engine bay pics.
As for the rest of the car, it looks a lot better driving by at 90mph than it does standing still. I pulled it out of a field where it sat for years. At this point it's pretty well sorted mechanically and aesthetics are next.
I've got a euro rear bumper and a 924 CGT front bumper getting installed while it's in for paint, (hopefully in the next couple months) and early turbo cup mirrors on it now. Other than that it just looks like a lowered 944 on Joengblood Racing wheels. I'll definitely gets some pics posted after the paint job.

JRP944

Great! I look forward to some more updates and good luck getting the valve spring issue sorted.

JRP

VilleJKL

Replacing AFM with MAF should do the trick power wise. Maybe it would be worth checking that Lindsay chip actually uses MAF reading to calculate fuel at WOT. 944 ecu with stock program uses fixed fuel values which would cause "lean" combustion with ITBs.

JRP944

This could also be the WOT contact on the TPS. As I had said before, the “wiper” inside the TPS had a bit of a loose fit on the throttle shaft, and as such it didn’t always want to make great contact for both idle and WOT. You might be missing out on the WOT fuel enrichment due to lack of proper contact.

@Tony5 I updated the 3D model for the wiper to hopefully correct this issue and will send that to you along with some of the other documents and spare parts.

JRP

Ish_944

Tony, thanks a ton for the drive-by video! The difference in sound is clearly audible, even if you're not satisfied with the quality. The ITB setup's sound really reminds me of BMW M cars, for obvious reasons.

The loss of low-RPM torque is for me a bit concerning, because I normally use the car between 2-4k when just running around or transporting the family. This is why I put the 3l crank into mine. I wonder if this could be mitigated by lengthening the velocity stacks?

@JRP944 Have you made up your mind regarding the CAD data? Are you still willing to share, or was it kind of sold together with the hardware?

Tony5

I think the low end loss is somewhere between minimal and imaginary based on the completely different pedal feel. If it's real I still wouldn't sweat it for daily driver use, unless you floor it a lot at 2k rpm while driving around town.
For the plenum design to work I don't think the runners or velocity stacks can really be any longer. The plenum is getting close to the brake system and the oil fill is already a pain to get to. Maybe the plenum could be shrunk a bit but it would be at the expense of easy straight airflow into the trumpets.

Tony5

No real updates from this weekend. I got the throttle cable stop properly assembled, no more zip ties.
I managed to sneak out for an early morning 2.5hr drive and I'm still loving the noise, even if I know that bystanders are getting the best of it. I can hear some of the howl pretty well on a narrow road through dense forest and it's awesome. Had an elderly leather clad biker dude accost me at a gas station to ask what was under the hood. "Wicked" is how he described the sound. I can happily talk cars/bikes with almost anyone, but I usually find conversing with muscle car guys and Harley guys to be a lot like talking to a brick wall, so this was a new experience for me.

Still keeping an eye out for someone with quality equipment to get some proper footage.