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Tomorrow gonna load onto the trailer, go to the exhaust shop, and maybe dyno if we are lucky.
Todays accomplishments:
Brazed in the opti vent
Installed the Auxbeam switch panel
Wired in the fuel pump inertia switch
Cut, formed, and riveted in the shifter sheetmetal and installed shifter
Reinstalled hood
Rerouted fuel lines (hitting the hood)
Installed new PS reservoir (OE was leaking)
Checked fuel pressure (44psi engine off)
Installed shock tower brace
Grounded drivers side head to frame
Fuel pump, Rad fan, Coolshirt pump, and Overtemp & Low Oil Psi Alarm override.
All exhaust shops in town were either busy this week or wanted me to bring it by and give me a quote. Nah. I decided to just do it myself. Not the best and the flex tube might not last very long but we shall see.
OE down pipes My hack job modification.
I’m sure that flex tube will break. It’s just a matter of time.
I also had to cut a significant portion of the trans crossmember out to fit the 3” pipe through it. I had to reinforce it. I spent most of today doing that. Didn’t get a pic. Embarrassed to show that hack job. It holds the trans strong and flows exhaust through it.
First time it’s moved under its own power in 2 years. Drove it around the block quietly as possible tonight just to see if the clutch and trans were gonna work ok. Off to the Dyno tomorrow.
All of the sudden the power steering is whining really bad. It goes away if you let it idle for awhile but for the first 5 minutes of running it whines. And, my radiator fan seems to run now no matter if it’s commanded on or not. So I gotta chase that down.
Hoping the power steering pump survives the dyno tomorrow.
Gonna post some results. First I want to show the previous dyno results from the 305 TPI engine I was racing with. This engine's bottom end lost oil pressure and needs rebuild. So I decided for an LT1 swap to get some better overall performance and reliability.
This 305TPI engine has 350 vortec heads milled down for 305 compression and ran shorty headers per class rules. Notice its power band was realistically from 2750rpm to 5300rpm topping out at 4600. Useable RPM range was very limited and average horsepower and torque were way down. 145hp@2750 rpm increasing to 255hp@4600rpm.
Before: 305 TPI Dyno Chart.
The next picture is of the LT1 dyno today. And the Dyno says 275hp / 315tq at the wheels. Runs super smooth and pulls smooth down to as low as 1000rpm. Incredibly happy with todays results. Just the fact the clutch held, and nothing broke, the car runs smooth, sounds super healthy. I couldnt be happier. Notice the average horsepower for the entire curve and also notice instantaneous torque all the way down low. The useable RPM range is from 2000rpm really all the way out to the rev limiter of 5900rpm. 150hp@2500 and 262@5300 but i can stay in gear up to 5900 which is likely to reduce the number of gear changes needed to stay competitive during a short or medium high speed straight. Although both engines were within 7 peak hp and 4ftlbs of torque, the LT1 looks way better on a graph to me. We shall see if it results in better actual performance on the track in traffic with my Camaro Mustang Challenge friends.
LT1 Final Dyno with 42mm restrictor plate. 262hp/308tq. Thats 2hp over and per my rules I'll have a 25lb penalty. Oh well, I probably gained 25lbs over the holidays anyways.
Eric @ AGN Motorsports is a true racecar guy. Although he specializes in 11,000rpm 600hp All Motor Hondas, he likes to see the American Thunder roll into his shop occasionally. Never charges much.
A bit surprised the descent of your torque curves at higher rpm are virtually the same between the two platforms. Wondering if that is due to you still using the “Y” TPI air filter housing?
A bit surprised the descent of your torque curves at higher rpm are virtually the same between the two platforms. Wondering if that is due to you still using the “Y” TPI air filter housing?
Im using a super cheap eBay cold air intake. I wanted to use the original intake but the LT1 intake manifold sits so much lower than the top of the radiator support where it rests. I also have a MAF to deal with now. So, I couldn't fit it all in there correctly. This cheap eBay CAI is only 3" diameter. If you look at the pictures, you'll see the MAF is bigger than the intake tubes. This might have cost me a few horsepower but I had to use a restrictor anyways as it was to get the HP down to 262hp target.
The torque curve looks like every other LT1 curve I've seen so far. Im not surprised. I am very happy with it.
Last edited by 64GunPilot; 12-10-2022 at 01:44 PM.
I could've swore the torque curve on TPI engines was more like this?
Maybe the shorty headers help out? I also thought the torque curve on the LT1's ran out a little farther than 4K rpm. I'm used to looking at mine with long tubes where the torque curve runs out a little past 5,000rpm before petering out.
His TPI was about as good as you could possibly get it to fit in the CMC rules. And yeah, that flex pipe isn't long for this world. One good off road adventure and that thing is hosed!
I could've swore the torque curve on TPI engines was more like this?
Maybe the shorty headers help out? I also thought the torque curve on the LT1's ran out a little farther than 4K rpm. I'm used to looking at mine with long tubes where the torque curve runs out a little past 5,000rpm before petering out.
A couple things. My old TPI had vortec heads and shorty headers. It also struggled to make the HP numbers, but had plenty of torque. Previous owner/racer installed an adjustable cam timing sprocket on the crank. I believe the cam timing was retarded 6 degrees to help up the horsepower while taming the torque down a bit. That might be part of the differences.
About the flex pipe.....we will see. Hopefully that crossmember can protect it to some degree. But I too believe this is a half measure. I need a professional shop to bend some pipe at the right angle to get it through there like that.
Here is a clip of the shakedown track event. Good day. No major breaks. Minor Stuff. Thank you for all the help from everyone on this thread. I could not have done it on my own. This forum is a great source. I am very pleased with the results.
Here is a clip of the shakedown track event. Good day. No major breaks. Minor Stuff. Thank you for all the help from everyone on this thread. I could not have done it on my own. This forum is a great source. I am very pleased with the results.
Im using a super cheap eBay cold air intake. I wanted to use the original intake but the LT1 intake manifold sits so much lower than the top of the radiator support where it rests. I also have a MAF to deal with now. So, I couldn't fit it all in there correctly. This cheap eBay CAI is only 3" diameter. If you look at the pictures, you'll see the MAF is bigger than the intake tubes. This might have cost me a few horsepower but I had to use a restrictor anyways as it was to get the HP down to 262hp target.
The torque curve looks like every other LT1 curve I've seen so far. Im not surprised. I am very happy with it.
V6 Y is different. Used one on a LT1 swap I had a hand in. MAF fits too and looks like it could have come from GM that way.
Here is a speed density swap using the speed density V6 Y.
Can you run scoops under the air cleaner housings or are they against the rules too? Those would help by supplying the filter housing with cooler air with the car in motion but not change the performance on the dyno. I am kind of a Smokey Yunick when it comes to cheating with rules that are not written on paper.
Look toward the end of this thread. Add the factory Y from a V6 and fab up some ducting if it is not against the rules. Then leave them wondering why you are motoring around people with the specified weight and power on the dyno.
I appreciate the help and advice. I’ve seen those pics from the LT1 swap guide. I wanted to do that, but didn’t think the MAF would fit. I could have hacked up my TPI bellows and made it work, but I chose this other route. I plan to reuse the TPI in another project later, so I decided to save my bellows and intake.
Unfortunately Ram air is specifically outlawed in our rules. Also our rules are written such that, if it doesn’t say you CAN, then you most definitely cannot.
That shifter bobs around quite a bit, how's your trans mount and is it tight?
For the PS pump, find a virgin LT1 pump and send it to Turn1 in MI to be rebuilt and modified. They do racks too by the way.
Edit: I posted the above at the 2:00 mark, am I good or am I good?
You're definitely more patient/cautious than I am. I can take it easy for 2-3 turns and after that it's full send even in a shakedown run.
I did make a few hard laps with it. 95% anyways. This was the first DE I went to that the faster cars had good competent drivers behind the wheel. I’m usually passing the z06s and the Porsches but not this time. So I had to lift at least once or twice per lap to allow them by. Anyways.
The transmission Mount bolt came out completely. Yea I see in the video it must have been coming loose for awhile. Just never noticed that on the track. Once it was completely out the trans slid back and forth around the curves and I could hear something clankin around so I ended the session and found the bolt missing. Loctite next bolt that goes in.
Last edited by 64GunPilot; 12-18-2022 at 11:44 PM.
I appreciate the help and advice. I’ve seen those pics from the LT1 swap guide. I wanted to do that, but didn’t think the MAF would fit. I could have hacked up my TPI bellows and made it work, but I chose this other route. I plan to reuse the TPI in another project later, so I decided to save my bellows and intake.
Unfortunately Ram air is specifically outlawed in our rules. Also our rules are written such that, if it doesn’t say you CAN, then you most definitely cannot.
Not only is ram air outlawed, we have our own definition for it. A couple years ago I made a shroud for my cone filter to keep hot air away. Before aiming some brake ducting at it which sourced air from the fog light hole I piloted that rule change. I think Fast forgets I'm a director. If OP is gonna cheat I think he knows better than to post it in his build thread.
Back to the trans though, keep an eye on the bolts that hold the mount to the car itself too. For some reason they all like to come loose, but that bolt you lost is the worst offender. To lose it in that few sessions I'd venture to say you just didn't have it tight enough the first time. And watch those 2 long torque arm bolts, they love coming loose too.
Not only is ram air outlawed, we have our own definition for it. A couple years ago I made a shroud for my cone filter to keep hot air away. Before aiming some brake ducting at it which sourced air from the fog light hole I piloted that rule change. I think Fast forgets I'm a director. If OP is gonna cheat I think he knows better than to post it in his build thread.
Back to the trans though, keep an eye on the bolts that hold the mount to the car itself too. For some reason they all like to come loose, but that bolt you lost is the worst offender. To lose it in that few sessions I'd venture to say you just didn't have it tight enough the first time. And watch those 2 long torque arm bolts, they love coming loose too.
Yea, that bolt was too long and I had several washers so I could get the proper torque on it. Idk. I’ll put loctite on the next one.
Im still new to this class and still in rookie status. Last thing I need is to be labeled a cheater. As a rookie, if I ever do win a race, the other racers will scrutinize the crap out of my car. Also once a cheater always a cheater. Hard to live it down. An honest mistake is not a terrible DQ, but intentional is not the reputation I want in this community. Not only that, winning in this class is specifically about car setup skills and driving skills. That’s why I love it so much.
As a rookie you have a lot of wheel time ahead of you (if you're like most) before you get to the pointy end. I once beat a car that was 25whp over (showed up out of the blue with no Dyno so we sealed his hood after the weekend). I've also had my car work some magic which forced me to redyno and plate down mid season. A few extra hp isn't going to be night and day. It can create opportunities, but it's not a game changer. Plus it's a good way to get blacklisted. Better to invest in yourself.
Edit: I wanted to add this to clarify that I don't believe you have any desire to cheat, the above was more of a generalized statement for other readers. If you've never done this, the things that you think will make you faster won't and the things you think won't will.
12-07-2022, 01:48 AM
