1000whp + 160mph 1/4 or bust build thread

So to start off I am opening this thread to detail my journey. I've built several cars and never documented it and this would be a shame to forego

Run down
2003 Sonic Blue Cobra with 64k miles I purchased as a complete roller with trans, built engine, ported C heads, stock blower, etc for $11,000 from a great member here. Quickly this snowballed into where I am now. Currently I am $8000 into the Cobra after selling the stock blower / headers.

Goals
primary goal 160mph capable car that’ll run low 4’s 60-130
1000whp+ secondary goal however the trap speed is way more important

ingredients:
4.6 Teksid with K1 rods, CP pistons, stock crank, and ported C heads with stock cams. All ARP hardware everywhere.
Racecraft K-member
CG fab SX400 single turbo kit with 4” downpipe
Turbosmart 45mm Hypergate and 50mm BOV
CG fab cold side
Fore lvl 2 3x 450’s
ID1300
T56 Magnum stock gear ratios
3.90 rear gear IRS with complete Steeda bushing kit
McLeod RXT 1200HD with McLeod 8 bolt steel FW

the engine will be back to me within the next week or so. the only thing i don’t have picked out is a turbo. stuck on a 76/88 SX400 ETRHO from Forced Inductions with a 1.25 AR T4 or a 7675 PTE

i will be taking pictures of all my progress so i will update as things go

thanks for stopping by

Low 4's 60-130 on the street is nothing to sneeze at. A somewhat attainable goal, but you're going to need more power. I would go with a better/bigger turbo, some Todd Warren custom cams, and you'll need a plan to manage power delivery. Either boost by gear or boost vs time. Traction control via a standalone computer helps tremendously. I assume you have 15" wheels on the back? With a stick, you'll have a hard time making those low 4 sec dreams come true if you are talking about those times from a roll. Good luck

Thanks for the advice. At this time my build is locked in the way I have it and I believe will carry me to my goals. I'm curious on why you're suggesting a larger turbo that a Borg SX400 76/87 as that's a big unit for a 4.6 especially at a 1.25 AR and a stick. That turbo should carry me to ~1100whp pretty easy which would be a mid 4 second car from a roll. I agree a 7675 PTE is going to be begging for mercy on my setup that's why I'm leaning towards the Borg. Most cobras have been trapping in the 150-160 range with 950-1050whp which should be a 4.3-4.6x 60-130 car from what I've seen. This is probably my 10th build so I don't expect to hit my numbers right off the bat however I am confident my setup will get me there after dialing it in. As far as tires I'll be making it happen on a 17". I've had a few 135-145mph 7-850Rwhp stick cars that did well on 17" so I hope my luck continues however not afraid to go to a 15" if need be. Not so obsessed with the ET as I am with a car that just is a riot/handful on the highway. A guy with a very, very similar build - AC - Ported heads but + cams went 9.1@156 recently on a sx476 6spd IRS car and I believe he's on a 15" or 17"

Sounds like a great build. The IRS is going to be the weak link here. Need to definitely get it on Bias Ply for a shot in hell to make this hook on the street.

Mack Verde said:

Thanks for the advice. At this time my build is locked in the way I have it and I believe will carry me to my goals. I'm curious on why you're suggesting a larger turbo that a Borg SX400 76/87 as that's a big unit for a 4.6 especially at a 1.25 AR and a stick. That turbo should carry me to ~1100whp pretty easy which would be a mid 4 second car from a roll. I agree a 7675 PTE is going to be begging for mercy on my setup that's why I'm leaning towards the Borg. Most cobras have been trapping in the 150-160 range with 950-1050whp which should be a 4.3-4.6x 60-130 car from what I've seen. This is probably my 10th build so I don't expect to hit my numbers right off the bat however I am confident my setup will get me there after dialing it in. As far as tires I'll be making it happen on a 17". I've had a few 135-145mph 7-850Rwhp stick cars that did well on 17" so I hope my luck continues however not afraid to go to a 15" if need be. Not so obsessed with the ET as I am with a car that just is a riot/handful on the highway. A guy with a very, very similar build - AC - Ported heads but + cams went 9.1@156 recently on a sx476 6spd IRS car and I believe he's on a 15" or 17"

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Mark, you have the makings of a very nice build without a doubt. I've been 3.80's from a roll on the street with 1200whp through a turbo 400. My new setup (1500+) will be 3.60's or better. I can tell you this, track times have nothing to do with what power you can put down on the street. I know when my car ran mid 4's four years ago, it made about 1000 through the 400. The dragy is an incredible device, but it can also be a heartbreaker. It will be much harder to do all that through a stick also.

When I was 900ish wheel many years ago, I had a big problem trying to plant the power down on the street on a 17" radial and had to move to a 15". I still would do more turbo also btw, an 83-88mm. You don't want the turbo maxed out, you want to be right in the efficiency range. Good luck on your build

Go with the 80mm over the 76mm. I have had three Turbo's from Julio and the 80mm spooled up just as fast as the 76 and made a lot more power.

But the 85mm spooled up almost as fast as the 80mm and I made over a 1000 whp on 93 pump gas with the 85mm so thats probably a better choice for u and u need an auto. Wont happen with the stick imo.

badcobra said:

The dragy is an incredible device, but it can also be a heartbreaker.

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Ain't that the truth!

Agreed with everyone in here, you need more than that 76mm. You're not in a class so no need to hinder the performance of the car using such a small compressor inlet.

Yes the draggy has broken many of my heart's but helped me get the car where I needed it

So you guys suggesting go bigger on the intake side maybe a 78-80/87? Looks like I might be grabbing a set of turbo cams and I need to make sure I don't mismatch them to the turbo

Mack Verde said:

Yes the draggy has broken many of my heart's but helped me get the car where I needed it

So you guys suggesting go bigger on the intake side maybe a 78-80/87? Looks like I might be grabbing a set of turbo cams and I need to make sure I don't mismatch them to the turbo

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Yes definitely go bigger. Look for an 83-88mm compressor wheel so you're only doing this one time. You'll have to cut all the supports and lip off the radiator and push it forward most likely to get enough room. Contact Todd Warren Cams for your custom cam selection. If you are not on Facebook, you can email him at [email protected]. With a big ass turbo, the right cams will make it all work and Todd has this down. Good luck.

So Todd and I are working on a grind now

Forced inductions is building me a SX400 76/87 1.10 AR divided T4 housing with the upgraded exhaust wheel and race cover. He was very confident in that turbo supporting my goals. We also talked about a 80/93 but he felt it may not be as responsive for a stick car