Whats the right amount of horsepower?

Old 09-18-15, 11:55 AM
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Whats the right amount of horsepower?

Yeah yeah I know, you can never have enough. Well, Im wondering what a good amount of horsepower would be for my ls1 swap. I was thinking 400, but then started to think I might want 500..

Anyone, speaking from experience, know if 400 hp is enough in an rx7? or if 500 hp is too much for the street in an rx7? Whats the cap for the street before it becomes impractical as a weekend/daily?
I have a 93 fd Btw.
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Old 09-18-15, 11:56 AM
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Will be a street car only, wont be tracking it
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Old 09-18-15, 06:03 PM
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I feel like between 450-500whp is perfect for Houston.
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Old 09-18-15, 06:28 PM
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So the car still runs pleasantly at 450-500 horsepower?
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Old 09-19-15, 10:28 AM
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Originally Posted by gabescanlon View Post
So the car still runs pleasantly at 450-500 horsepower?
With Toyo R888's it is great as long as it isn't cold or raining.
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Old 09-19-15, 10:53 AM
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400whp is plenty fast on most tracks on performance street tires. you can never have enough on long straights. in other words, if your rush comes from trying to bury speedo needle as fast as you can on freeways, you will never ever have enough whp. do keep in mind though, at over 400-500whp, you can literally kill yourself and other people quite easily. so respect the power and be safe. at double or triple the power, it can only take a split second of misjudged WOT to ram into other cars, trees, and people. I only say that because it sounds like it's your first time going into 400-500whp range. it's quite something else.

Last edited by stickmantijuana; 09-19-15 at 01:35 PM.
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Old 09-19-15, 11:48 AM
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Most race cars (touring, ALMS, etc) have about 400HP. Any more and it becomes harder to drive fast.
Spinning tires don't make you go faster. heh, They just make it scarier.

On the other hand, I agree with stickman. If you wanna smoke people at stop lights and "light 'em up" then by all means, put a 500R in there, turn up the boost, and don't forget the fuel rail.
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Old 09-21-15, 05:55 AM
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Are we talking HP at the wheels or at the crank? My old FD had 330hp to the wheels and it was pretty fun and enjoyable to drive. Most days it felt like it was more than enough for a daily driver. I agree with stickman and Natey. Personally I found out that it was better for me to invest time at the track learning to drive faster than to add HP. The car was much easier/enjoyable to drive when I was not trying to fight the steering wheel etc. Keep in mind that your tire will also make a big difference as to how the car behaves. Sometimes its best to work your way up and see where you are comfortable before you find yourself in serious trouble.
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Old 09-29-15, 03:07 PM
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400-450 WHP will be a VERY fast car. There will be few cars on the road that can hang with you.

My FC has 400 WHP and is a bit lighter at 2600 lbs. At the track the car pulls on or hangs with nearly everything on the straights.. New Vipers, 458 Ferraris, Turbo Porsches, C6 Z06s.

In a FD street car 450 will get the job done but you will need big tire's to really use the power. As you get past 525 or so WHP it will become unusable. The sweet spot is between 400-500 WHP depending on your skill and setup.

Last edited by LargeOrangeFont; 09-29-15 at 03:09 PM.
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Old 09-29-15, 04:01 PM
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I do know 420/420 rwhp/rwhtq in a turbo rotary isn't enough in a 2,500lb FC for me.

However, you only need enough HP that you are never at full throttle.

I never once spun the tires in 5th gear even at full throttle.

For an LS swap I would aim for 1,000hp and turn the boost down for reliability if you never find yourself using full throttle.

That is my plan if I LS the FD. I mean, a twin turbo kit is the same price as a pair of LS swap headers- so why not?
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Old 09-29-15, 06:55 PM
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Originally Posted by LargeOrangeFont View Post
400-450 WHP will be a VERY fast car. There will be few cars on the road that can hang with you.

My FC has 400 WHP and is a bit lighter at 2600 lbs. At the track the car pulls on or hangs with nearly everything on the straights.. New Vipers, 458 Ferraris, Turbo Porsches, C6 Z06s.

In a FD street car 450 will get the job done but you will need big tire's to really use the power. As you get past 525 or so WHP it will become unusable. The sweet spot is between 400-500 WHP depending on your skill and setup.
Agreed with everything.
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Old 09-29-15, 09:26 PM
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Originally Posted by BLUE TII View Post
I do know 420/420 rwhp/rwhtq in a turbo rotary isn't enough in a 2,500lb FC for me.

However, you only need enough HP that you are never at full throttle.

I never once spun the tires in 5th gear even at full throttle.

For an LS swap I would aim for 1,000hp and turn the boost down for reliability if you never find yourself using full throttle.

That is my plan if I LS the FD. I mean, a twin turbo kit is the same price as a pair of LS swap headers- so why not?
FWIW I'll be upping the power to about 450 WHP and calling it good. The car lays over in 5th, but part of that is the tallish 5th gear in the T56 I have in the car. I can't fix that without swapping the trans.
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Old 09-30-15, 11:25 AM
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This 20b has made over 740rwhp on 22psi, with plenty of room to go. I built the car for big HP and hardcore interstate pulls.

Truth is, after a year of building it and dreaming of these huge #'s, lowest boost possible @ 10psi 500rwhp scares the living **** out of me in 1st and 2nd gear!

I've swapped out the wastegate spring to run a max of 12-13psi, and have never even tried more power than this besides the dyno!

550-600rwhp in an FD is just flat-out insanity. Anymore and you're a nutjob. This car barely stays planted in 3rd gear at WOT at 13psi. Its stupid, overkill. I feel ridiculous for choosing an 80mm turbo and shooting for 800hp.

This isn't a supra or a GTR, its a lightweight toy machine.
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Old 09-30-15, 05:48 PM
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Originally Posted by LargeOrangeFont View Post
400-450 WHP will be a VERY fast car. There will be few cars on the road that can hang with you.

My FC has 400 WHP and is a bit lighter at 2600 lbs. At the track the car pulls on or hangs with nearly everything on the straights.. New Vipers, 458 Ferraris, Turbo Porsches, C6 Z06s.

In a FD street car 450 will get the job done but you will need big tire's to really use the power. As you get past 525 or so WHP it will become unusable. The sweet spot is between 400-500 WHP depending on your skill and setup.
Stamped & approved.
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Old 09-30-15, 10:47 PM
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Mosnterbox said it best, numbers arent the same for thee things as they are with other cars. At 468 WHP my last LS1 fd was fast enough to hurt plenty of 900 hp club feelings at the track.

People get caught up in the hp numbers and disregard all the other variables that should be considered.
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Old 10-08-15, 07:15 AM
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For my S2000, ~150hp (about what it makes out of VTEC) is sufficient for 99% of my street driving.
For the FD, ~525hp was only enough for ~185 in the standing mile, so obviously it needs more. Hence new 6.9 LS3 now installed, bout to get dyno tuned
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Old 10-08-15, 07:28 AM
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Mine currently has 305whp and will be mainly road course/nice weather used. It is power to weight faster than my previous higher HP cars (2005 E55 AMG/2011 Mustang GT) and feels it especially since it does not have any nanny assistance.

My plan is to get used to what I have and then maybe add longtubes and a more aggressive cam to get it to around 400whp and call it a day after that.

I can tell you that tires make a huge difference in the usability of the power. When I got the car it had 255/40/17 tires on rear that were run flat and you could get sideways very quickly at even higher speeds/gears. Now has 275/40/17 Nittos and the grip is so much better and more friendly.
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Old 10-08-15, 06:36 PM
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400-450 is more than enough on a V8 FD
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Old 10-12-15, 08:12 PM
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Best guess my FC is somewhere a little north of 550 rwhp (429 LS2 stroker with a great deal of breathing work). After I lost it lighting up third--on 295 summer tires and 3.55 gears mind you--I can say that's a bit too much power for the street. Worst part... I have a racelogic box setting on the shelf I hadn't gotten installed.

Damage wasn't bad, but it was a bit odd to feel like I actually found the limit of fun street HP.
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Old 10-14-15, 04:28 AM
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It's funny, at 420whp and 375rwtq I could easily walk c6 Zo6's and lightly modded gt500's. The combo wasn't right though. Felt like a dog down low. Completely redid the top end. Gained at least 30whp and 40rwtq and feels awesome down low. I will tell you that about 450rwhp is about the happy number. Sure there will always be fast cars on the long interstate but on the track it's just right with some 180 tread wear summer tires. Or r888's if you really want to stick.

My vote is for 400whp with 220+ tread wear tires and 450whp for softer tires. I can tell you that 300 tread wear 285 wide tires is freaking useless with 375rwtq in 1,2 and 3rd. (4.10 rear)
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Old 10-14-15, 11:51 AM
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300 tread wear 285 wide tires is freaking useless
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Old 10-15-15, 04:28 AM
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Unless you are driving a long way and don't have a big tire budget. I'll certainly never buy them again but as I said in my last line. They are useless indeed unless it's your daily driver.
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Old 10-15-15, 12:22 PM
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Yeah, it just seems to me the primary market for high treadwear wide tires is people who buy an expensive performance car and then wear the stock high performance tires out in no time.

They cheap out and get low performance tires because they are cheaper and will last longer and they don't drive their cars hard enough to notice a difference or care.

Really, they would be better off with the non performance version of their car that came with narrow wheels and tires or at least those wheels/tires.

A 285 sucks in the rain and snow whether it is an all season or not- would be better off with a 245.

That is all I mean.
A performance tire size in a non performance compound just seems like a poor compromise to me. Even for just looks, anyone who knows performance looks at a car's tires first when judging a car's performance potential.
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Old 10-15-15, 05:58 PM
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Absolutely agreed. In fact, when someone is talking trash I will just look at their tires and be able to see if they are serious or not. Above 100 tread wear and you won't get my respect, lol.
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Old 10-15-15, 07:42 PM
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Treadwear numbers are not directly correlated with grip. Particularly grip on the street. At 50F in normal street driving conditions, good high treadwear all-seasons can have significantly more grip than Max or Extreme perf summer tires.

Best tires for grip depends on usage conditions. And even for dry track usage you shouldn't assume lower-treadwear # => more grip. There are tires that have poor grip and wear out quickly.
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