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My search for better performance


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2seater

I thought I should continue the Reatta story a little bit further. I have been looking for photos of the first long distance trip, and I can see them in my minds eye, but they may not be digital being from about 1996 ?

 

Anyone that has seen my posts with mostly performance "adjustments" knows these aren't professional in nature but more of a trial and error process, plus it is a learning experience. I will try to synopsize what and where I have looked for improvements with varying levels of success. 

 

Initially in the '90's it was the usual homemade air intake with a cone filter. Then it was a colder 160 degree thermostat sourced from a vendor of Grand National parts and tuning. This was coupled with a new PROM from ED Wright at Superchips. This had the net effect of a slight increase in performance at the higher end at this expense of low speed crispness and requirement for premium fuel. Also had the coolant fan operations changed to match the thermostat. 

 

Along the way, discovered and corrected the rear exhaust manifold restriction plus had all of the engine exhaust parts ceramic coated inside and out in titanium gray with heat shielding eliminated. That worked just fine and looks good, but costly. They hang on the wall now. Around this same time, about the turn of the century (which I never thought I would say), I spoke with a guy in Iowa that worked with the GN guys enlarging stock throttle bodies. I sent him one and he machined it larger internally and made a new throttle plate to match. The bigger throttle does have a tiny effect but I had to close it almost to the point of sticking in the bore to get the idle down. This same guy made an adapter cone for my first turbo to throttle body connection when that experiment began. Somewhere in there I removed the cat and replaced with a straight pipe. This was about the same time I came upon a flowbench forum that promoted homebuilt plans and techniques. I believed it evolved to be called Flowbench Tech now. I did build a very simple but reasonably powerful bench of my own which I used at first to test things like the stock cat. vs the straight pipe and later a replacement cat. 

 

Not satisfied, I purchased a junkyard engine, an '89, to "build". Bored .020" over, L27 replacement pistons with more compression height to approx. zero deck, hand ported stock heads and first use of flowbench for conventional testing. All very Rube Goldberg but educational. The stock engine with 92k miles on it went on a stand and parked in the corner. The new engine worked well. Definitely gained some performance in conjunction with my previous items. Of course I couldn't leave that alone so decided to try turbocharging since I had a welder and various collected used turbochargers. I also collected used exhaust manifolds and I think this is when I brought a used camshaft home from a donor engine that I was stripping of parts to cut up and modify. More on that later. This where the throttle body adapter comes in to blow directly into the MAF from the compressor of the turbocharger. A friend donated some used GN injectors and the whole works was built and installed with the replacement engine still in the car. The first drive was a revelation. The faster I went, the faster the car wanted to go. It boosted very quickly and it wanted to go. I had no tuning at this point, just the stock chip. Two things come together here, caused by my lack of knowledge. It boosted very quickly and had knock issues. This is when I got involved with Ryan at GM Tuners and he burned several chips for me over time. I had put together an engine that worked well naturally aspirated but when turbocharged, the quench or squish distance was in a bad place for suppressing knock, plus there was no intercooler to cool the inlet air. Over time we got it better, adding alcohol injection, changing the fueling and timing, adding a tps improver to get full fueling earlier, but the factory ECM can only read up to 170gm/sec and we blew right through that threshold within seconds of launch. That meant everything beyond the ECM charts was a guess. It did work well but had to be relatively gentle and aware. I put about 38k miles on that engine in both N/A and turbocharged form. More to follow

 

Photos: First gen Flowbench from 2005, raw first gen turbo piping B4 black ceramic coating from 2003, first ceramic coated stock exhaust manifolds and first turbo installed from 2005

Flowbench with MAF.JPG

Turbo piping.jpg

20190405_223617.jpg

Reatta turbo left.JPG

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Ronnie

I really enjoy all these interesting Reatta stories. All of them have been great. I hope we get more of them.

 

2seater, I knew you had added a turbo but I didn't know you had done so much experimenting with enhancing performance. That was a great story and the photos tell a story of their own. I look forward to more. Your story tells me how much time and effort you have put into your Reatta. I look forward to reading more. I would have been doing something similar a coupe of decades ago. I just don't have the get up and go anymore.

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Ron Walker

This may not be the place to comment on 2seater's post above, but I'm curious about whether all the performance mods made (and it seems extensive) yielded measurable improvement, in say 0-60 times, 1/4 mile times, etc. and whether any mods to the transmission were necessary for the improved performance. 

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2seater
2 hours ago, Ron Walker said:

This may not be the place to comment on 2seater's post above, but I'm curious about whether all the performance mods made (and it seems extensive) yielded measurable improvement, in say 0-60 times, 1/4 mile times, etc. and whether any mods to the transmission were necessary for the improved performance. 

I was a little hesitant to post this stuff in this thread but it seemed like an extension of the introduction topic. I know I am straying way outside the intention of this thread which is to provide a place for newbies to introduce themselves. I would be happy and maybe more appropriate to create and move some of this content to a different space? I do enjoy discussing this stuff but it is pretty narrow in focus and the last thing I want is to pontificate because it is all about learning and experimenting for me. I have posted lots of stuff in the past about many engine related items but it seems there has been little interest. What say you Ronnie??

 

In answer to the performance increase: I have little concrete evidence because I try to restrain my right foot so as to preserve the rest of the drivetrain, which is all stock at this time at 144k miles. I do have early scan tool data from a Auto X-Ray that I sent to Ryan at GM Tuners to try to work out a chip. Later I used a laptop and TunerPro software and I now work on my own PROMs. I can tell you that the initial aggressive trials the LV (load value) of 255, which is the maximum, and is the Y axis of the timing chart, would be exceeded in one frame, which is about one second or a bit more. The best way I can suggest to monitor any performance improvements one might do is to watch the MAF reading. From info gathered over the years, our stock engine is around 65% VE so it boils down to 1.32 times the MAF reading in grams per second is the approximate horsepower being produced. Even if the onboard sensor isn't totally accurate, if used for comparison purposes, it can be useful to see if the butt dyno is correct. As long as the engine is pretty much unchanged internally, increasing flow in and out should increase performance. Of course atmospheric conditions, altitude and other factors need to be monitored as well because it does make a difference, especially in an N/A engine. From the scant data I have collected, a stock '89/'90 will max around 125gr/sec, an '88 will be over 130gr/sec, and have no data on a '91. In my stock '90 engine, but with a used '88 cam cam in place, I got up in the 138-140gr/sec area under similar conditions from the 125 baseline. As it is now with the original engine around 100k miles, with hand cleaned up and mildly ported heads, enlarged T/B, and the aforementioned '88 cam, plus turbocharged to a maximum of five psi, the car will step a little to the right if the throttle is jabbed from a stop. This is with 225R55/16 VR directional tread summer tires. How's that for a non-answer ?

 

 

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DAVES89

I find what you are doing to be interesting, but as you know it is beyond my scope of doing, so I usually post no comment.

 However as some of us know, when I was to the point where I wanted to swap the engine trans [rebuilt trans] you were instrumental in pointing me in the right direction with the '88 cam and higher compression pistons. Then of course the porting of the heads a bit and cleaning up the exhaust.

 And using your formula I calculate I am about 180-185 HP. Not the 200 I was hoping to get to, but enough that I really enjoy putting my foot in it on an occasional basis. And because the engine isn't overbuilt I don't have concerns about blowing out the tranny.

 

 

 

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Ronnie
36 minutes ago, 2seater said:

What say you Ronnie??

As long as people are posting on the forum I'm happy. When it gets quite is when I get discouraged. If you would rather have a topic about performance that would be OK. I'm fine with it either way. I always enjoy reading what you post about performance.

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2seater

Okay, I will keep it here. I figured it was a sort of continuing story but I don’t want to put people off either. Thanks 

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Philbo

2Seater, I really enjoy reading your stuff actually even if I don't comment on it. I would love to get into that stuff more myself some day. Also I've been on other forums where the moderators are such sticklers for what you post and where and all this stuff. I want to say I really appreciate how chill you all are. 

 

I plan to do an intro myself soon, just have to carve out the time ?

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Ron Walker

Thanks 2seater. Your explanation is, well, a bit over my head. I do understand "step[ping] a little to the right if the throttle is jabbed..."

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DAVES89
2 hours ago, 2seater said:

Okay, I will keep it here. I figured it was a sort of continuing story but I don’t want to put people off either. Thanks 

I could always revive my series of posts on my engine/tranny swap. I think it is interesting and has real input from Ronnie and 2seater

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2seater
1 hour ago, DAVES89 said:

I could always revive my series of posts on my engine/tranny swap. I think it is interesting and has real input from Ronnie and 2seater

You have actually done more extensive work in that area than I have, more than once if I remember right. I just pull the engine and work on it at my leisure on a stand, hence the need for another so the car isn't down. My projects are always slow moving and sometimes take years?

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2seater
2 hours ago, Ron Walker said:

Thanks 2seater. Your explanation is, well, a bit over my head. I do understand "step[ping] a little to the right if the throttle is jabbed..."

All it boils down to in the long winded explanation is the engine is just an air pump, so anything done to make it pump more air, is generally good. If the built in efficiency of the pump is not changed, then using a gauge or meter of some kind, the MAF in this case, can be used to get a sense if that ram air, or fancy muffler or some such thing just installed actually improves the throughput. Sometimes the brain can be fooled by the sounds and visceral feel. I know, I have the tee shirt? I know I have learned things aren't always what they appear to be and the factory did a pretty good job of matching all the parts, so improvements without major surgery will be in small increments.

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2seater

I will try to pick up where I left off. The replacement engine I had built, with a measured and calculated compression ratio of 9:1, was fine normally aspirated, but I didn't know enough at the time that reducing compression for adding boost would have been much better, but of course it didn't start off with boost in mind. I was so unconfident in my first attempt at turbocharging that even with the wrap around piping to bring the rear exhaust to the front, the entire turbocharger assembly could be unbolted and removed and the stock crossover pipe under the throttle body could be dropped in place so the engine would revert to N/A operation even though the exhaust path was non-conventional. I was glad I did that even though it required some compromises to what would work best. I actually did that a couple of times while trying to get knock under control. This was my daily driver in summer months. Aside from the compression ratio boo boo, the wastegate on the turbo wasn't designed to keep the boost pressure down far enough while working out the bugs. It would spike up to 10 or 12 psi despite being set for about 7psi, or 1/2 a bar. I did drive it like that for several years and put about 38k miles on it but then it started to lose oil pressure, most noticeable at low engine speed and idle.

In the mean time I had installed a fresh timing set and the used '88 camshaft in my original 92k mile original engine. I had written down of the original '89 camshaft lift and duration when I disassembled the junkyard engine described previously. I did the same for the '88 cam and then did a hand plot on graph paper for the two of them. The '88 has more lift and duration on both lobes so a plot shows the '89-'90 cam lobes fit completely inside the '88's. I had stumbled onto a good thing, in my opinion, completely by accident. With that in mind, the rebuilt engine was pulled and the original engine reinstalled, in original N/A form.

A dissection of the rebuilt engine revealed the 2nd design timing chain tensioner was worn completely through in one section causing the chain to become tilted and the front cam bearing was worn badly. I believe this was the cause of the dropping oil pressure as that front cam bearing is the first in line from the oil pump pressure passageway. Photo below. My belief is the Cloyes timing chain, which has a more saw like top surface, cut through the softer material of the later model damper. Comparing the Cloyes to the original Morse brand chain shows this to be true. 

 

Photos: This is a stock throttle body on the left vs the enlarged version. I just realized I have them rotated 180 degrees from each other so it looks like different models, but it's not.

The two chain dampers referenced above, the left being the 1st style with 92k miles on it and the 2nd design, and the way I found that destroyed damper with 38k miles. A crude hardness test with a spring loaded center punch revels the original style damper had a much harder plastic rubbing surface vs the second design. Poorly designed IMHO. 

DSC01025.JPG

DSC00975.JPG

DSC00969.JPG

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Ronnie

Good write-up Hal.  You describing how your throttle body was modified reminds me of a huge 2 barrel carburetor Jon Kaase made for a friend of mine back in the '70s. You may have heard of Kaase. He builds a lot of engines for the Pro-stock drag racers now. There is an interesting story on how Kaase building that carburetor came about. My friend TF Harrison had a '68 Camaro with a 427 and Kaase had a  Mustang from about the same year with a 427.  Both had four barrel carburetors. They were both in the same IHRA class and both of them wanted to be the World Record Holder in their class.

 

We were going to all the same big IHRA races all over the southeast that Kaase went to and we got to know him pretty well. At that time it was class racing where your dial-in was the world record E.T. in your class when you raced against cars in other classes. You couldn't just write your dial-in on the windshield with shoe polish like most drag racers do today. TF and Kaase kept bumping up the record when they ran against each other in their own class and doing that was hurting both of them when they had to race people in other classes for the eliminations.

 

At one of the Rockingham, NC races Kaase came over to TF and said he wanted to make a deal with him to stop the record bumping that would allow both of them to be record holders. Kasse pulled out a two barrel carburetor that he had modified by boring it out so big that it cut into the body of the carburetor and had to have a sleeve put in it (much like pressing a sleeve into an engine block) and a new throttle plate had to be made as well as a lot of other modifications. He handed it to TF and said, "!f you will get out of my class I will give you this 2 barrel carburetor for free and I guarantee that you will be the record holder in the two barrel class." TF asked him why he didn't put the two barrel on his car. Kaase said he was sponsored by Ford and they wanted him to keep his Mustang in the four barrel class.  TF agreed to give it a try and signed up in the two barrel class. TF's E.T in the 1/4 mile only dropped about a tenth or so with that two barrel. He set the record in the two barrel class at that race and held it until he flipped his Camaro on it's top near the end of the racing season. When he built a new Camaro race car he switched to a small block for the coming year and started running a four barrel again.  TF's had several race cars over the years but he has always kept that carburetor that Kaase made for him but never ran it on any other cars. He still has it in his garage as a conversation piece.

 

P.S. If you take a look at the rear quarter on the Camaro it has IHRA World Record Holder written on it.

 

TFs Camaro].jpg

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2seater

Great story! Yes, I do know who John Kasse is and he is still going strong. A lot of Ford stuff, the Boss Nine heads being one. Not limited to Ford though and a very tough competitor in the Engine Masters competition using different brands. A master of finding ways to bend contest rules without breaking them, a sort of Smokey type.

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Ronnie
25 minutes ago, 2seater said:

A master of finding ways to bend contest rules without breaking them, a sort of Smokey type.

Yep. You just described the Jon Kaase I knew.

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2seater
19 minutes ago, Ronnie said:

Yep. You just described the Jon Kaase I knew.

Yah, two inch thick head gaskets on a Y-block?

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Padgett

Years ago I helped Glen drop an L-67 and 5 speed Getrag into an 88 keeping the digital dash. Today might do something different but cheated, bought a nice 89 Allante with 273 lb-ft of torque for chump change. 270-300 lb-ft of torque makes for a nice cruiser.

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Ronnie

Roy Johnson is another person TF use to race with.  He was a local guy from Greenville, TN that went to all the tracks we did I knew Roy well.

 

Later on after he got older Roy built engines for his son Allen Johnson who use to be a big time Mopar pro-stock racer. I always rooted for him when I saw him on TV.  I don't know if they are still in drag racing or not. Below is a photo of Roy's car when TF raced him in the '70s. The red headed guy on the right is my friend Dennis Tucker. TF's Camaro was in the left lane and out of the picture.  I was probably there somewhere.

 

roysdragpak004.jpg

 

EDIT: Looks like Roy and Allen retired from racing in 2017. That's Roy on the bicycle.

 

 

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2seater
2 hours ago, Padgett said:

Years ago I helped Glen drop an L-67 and 5 speed Getrag into an 88 keeping the digital dash. Today might do something different but cheated, bought a nice 89 Allante with 273 lb-ft of torque for chump change. 270-300 lb-ft of torque makes for a nice cruiser.

Was it Glen or Greg? My memory is cloudy but I think I know who you mean and miss his input. 

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