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So my goal is to break 200mph in the half mile with my car.
Currently the car is mid-engine, stock LS3 power (430hp), Quaife LSD Transmission….1800 lbs. 2000Lbs with me in it.
It will consistently do 160mph in the half and beats everyone to the 1/8 and 1/4 mile mark. Sometimes I beat em to the flag but my top speed is lower…so I lose. It’ll do 0 to 100 in just a hair over 3 seconds.
I want to install a new “normally aspirated” engine to get me to the 200mph mark. That’s a requirement.
I’d also like to stay with an LS engine as the rest of the car is designed for it…..computer, digital dash, Quaife bellhousing, Dry Sump system, etc….That’s a requirement.
I also need to “order” a complete engine as I don’t have time to do the work and reliable technical help is very hard to find…..That’s a requirement.
My current path is to just buy a “build to order” LS7 700 crank horsepower and see where that goes. My concern is it might have too much TQ and create wheel spin whereas now I have none…maybe just driver acclamation.
Any thoughts?
I have the same goal, but in the mile. Even at 2800 pounds I struggle for traction in my rx7. I’m building a 427, but using a Holley sniper, wide cam center, and a little bit extra exhaust duration to try and bleed off some mid range torque.
I’m shooting for a ~7500 rpm peak, and shift before 8000.
I considered a de-stroked engine but you do give up horsepower by losing cubes. I may one day build a short stroke engine if the chassis can’t take the torque, but for now I’m trying to make the 427 work as I need the power to meet my goal.
Heads? LS7 265?, 285?
Cam? Just big for top end?
Rockers? (I just don't want to have valve cover issues, been there)
Manifold? Just Stock LS7? or high rise with an elbow? I just want to retain current throttle system.
Thanks
I can tell you that aero is going to be just as much of a factor going 200 in the half as power will be. You really don't want the either end of the car getting light at those speeds, especially in a car that only weighs 1800lbs. Gearing is another factor. You want to be able to keep the engine in it's sweet spot as much as possible. Building an engine that revs north of 7000rpms will help.
From my experience with half mile racing, a full weight "street" car (ie. 3800lbs or so) needs about 1200whp to hit 200mph. I would think that depending on your aero, considering your weight, 750-800whp will get you there. I like Darth's idea of a smaller engine that makes its power with rpm rather than torque. It will help you get the power down out of the hole and the rpm will keep you in the powerband down the track.
What kind of car are you running? I see you're in socal. Are you going to the Shift S3ctor event at the end of the month? If you are, come say hi. We'll be the tent with the CTS V wagon and the 2JZ swapped FRS.
I have the same goal, but in the mile. Even at 2800 pounds I struggle for traction in my rx7. I’m building a 427, but using a Holley sniper, wide cam center, and a little bit extra exhaust duration to try and bleed off some mid range torque.
I’m shooting for a ~7500 rpm peak, and shift before 8000.
I considered a de-stroked engine but you do give up horsepower by losing cubes. I may one day build a short stroke engine if the chassis can’t take the torque, but for now I’m trying to make the 427 work as I need the power to meet my goal.
Oh Yeah......Traction is elusive with big power
I have a C6Z06 heads and Cam on E85, 590whp. Stripped down to 2950lbs. No traction in 1st, Maybe with 50% throttle in 2nd, roll to full in third......does 170-175 if I drive it right.....150 if can't leave my foot off it.
That car would probably do 200 in the mile.
I can tell you that aero is going to be just as much of a factor going 200 in the half as power will be. You really don't want the either end of the car getting light at those speeds, especially in a car that only weighs 1800lbs. Gearing is another factor. You want to be able to keep the engine in it's sweet spot as much as possible. Building an engine that revs north of 7000rpms will help.
From my experience with half mile racing, a full weight "street" car (ie. 3800lbs or so) needs about 1200whp to hit 200mph. I would think that depending on your aero, considering your weight, 750-800whp will get you there. I like Darth's idea of a smaller engine that makes its power with rpm rather than torque. It will help you get the power down out of the hole and the rpm will keep you in the powerband down the track.
What kind of car are you running? I see you're in socal. Are you going to the Shift S3ctor event at the end of the month? If you are, come say hi. We'll be the tent with the CTS V wagon and the 2JZ swapped FRS.
Yup.....other concern is at 200 it may take flight.....we'll see.
Car is a Palatov made in Oregon....kinda wedge shaped but may need more aero....then with aero will need more power, its endless.
If I go I won't be taking the Palatov because the motor is coming out.....Trying to complete new power by June.
As Doc350 describes above . . . aero is definitely going to be a factor. Wind drag here will slow you down. You really need to consider smoothing anything that catches air including the underside of your vehicle.
Rolling resistance in the tires will also slow you down. Look at what the Bonneville Salt Flat high speed guys do for tires.
It just needs to carry the acceleration that it has in the first 1/4 mile
I've had it to 170 before down the straight of willow.....it felt very stable.
But I could convert to the newer body style.
Yes on the new body style. Just the exposed front wheels and fenders on the first car is too "dirty" aerodynamically.
My engine and build in my C5 Coupe was Planned to do ~203-207 MPH in 1 & 1/2 Miles at Mojave. I estimated
550 RWHP @ 6700 RPM 5th gear (.8 X 3.42:1)needed for ~205 MPH (My Engine made 590+ RWHP).
In 1 mile ~800 RWHP, 1/2 Mile may need Power Adder even at 1800 lbs with good aero ~800+ RWHP.
That 197 MPH Corvette with excellent Aero and Long tail is making 820+RWHP IMO.
NA will require A LARGE Solid Roller and Big RPM 8000+ Minimum.
3.625" Stroke X 4.155" minimum bore, Big Plenum Short Runners, HIGH Compression, Race Fuel or E85,
Great Heads & Valvetrain, Dry Sump Oiling.... on and on.... $25K+
Turbo 5.3 junkyard for much less than 1/2!
LOL
Good Luck
Last edited by NAVYBLUE210; 04-06-2019 at 03:11 PM.
The primary force you're up against when going 100+ is air drag. Drag force increases by velocity squared. That means if you double your speed, you quadruple the wind resistance.
LS3 block will work with Darton MID sleeves which will allow bores up to 4.2" and along with studs top and bottom will make for a much stiffer stronger platform. A drive by wire ITB setup like Harrop with a pair of 400+cfm heads would see 8000rpm easily on a short stroke and love it. Stay small, big strokes make power but won't like WOT for extended periods at 8000rpm. Stock LS3 stroke is perfect and witha 6.125" rod gives you a great 1.69:1 rod stroke ratio. No power in that but it'll be happy singing the song of its people all day at high rpm
I'd be more worried about the Quaife trans. The boys in Supertourers over here in NZ had a LOT of issues with those 6 speeds behind STOCK LS7's with a very mild cam change (575hp). They're not even close to being as strong as the Hollinger.
As others have mentioned you need to make it more aerodynamic as that car will hit a brick wall above 160mph and the calculation is that you need 3-4x more power to go from 150-200mph not even factoring in aerodynamic challenges. You will not achieve it naturally aspirated.
I've driven/owned a bunch of FD RX-7's which are super aerodynamic.... one was a 427ci LS7 making only 520rwhp/472rwtq and it did 165mph in the 1/2 mile with a widebody kit and mirrors still on... no wipers.... windows up. A similar narrow body car with 595rwhp my buddy owned and 275/35/18's all around went 196mph in the mile (TX Mile 2009). My stock narrow body FD RX-7 with a turbo LS9 making 1000-1200rwhp (boost by gear and unable to use very much until 4th gear..... and then really pour in the power using 5th gear) went 195-198mph on a crappy surface (Coalinga airstrip) without traction control. We only had boost by gear/time via the Holley Dominator for traction aid. With traction control 200mph would be much more possible and certainly a less dirty track (pebbles/dust on track surrounding by agricultural fields).
The 441 is the way to go. Make the heads, intake and cam large enough and it will rev the same as a destroked engine. Stroke doesn’t limit rpm, airflow does. You’ll need cubes to make the kind of power you need, or go for a squirt of nitrous and keep the engine more usable in 99% of your applications.
The 441 is the way to go. Make the heads, intake and cam large enough and it will rev the same as a destroked engine. Stroke doesn’t limit rpm, airflow does. You’ll need cubes to make the kind of power you need, or go for a squirt of nitrous and keep the engine more usable in 99% of your applications.
Partly true. Given enough air flow a long stroke engine will rpm as high as a short stroke motor until it literally explodes.
Making a long stroke motor where pistons speeds exceed 5000fps live up there for extended periods is something only the very best engine builders can do.
Plenty of 441's pulling 8000rpm on the drag strip. Not so many lasting 1 mile, let alone doing that over and over like a short stroke motor could built to the same quality specs.
Can it be done?
Sure. There's people on here that could make that work (Kurt being one of them re the 441 listed for sale above - sounds like a good one)... but we're talking close to NASCAR level quality control to make a big stroke rpm ...for a long time
On that note - a refreshed NASCAR motor would be perfect lol
Thanks for the input.
I need more real test data.
I think what I'll do is slap H/C/I on it and get the power up to 600+ (from 430) then test it from there....
That's about 40% increase in power, then we'll see what it yields in speed.
Then we'll have the makings of an equation.
I've been nothing but impressed by this car since I got it.....on the track and on the street (yes.....its street legal)…...so maybe it has another upside surprise in it.
Ya know an F1 car is an "open wheel" car....1500lbs, approx. 750hp.....they hit 200 all the time during qualifying.
I know its not an F1 car and I haven't spent bazillions on wind tunnel testing....but it is "open wheel".....so that can't be totally bad.
04-05-2019, 09:33 PM
What LS Engine will take me to 200mph? 
