Hi,

I currently have a fairly built bseries in my hatch.

I'd really like an additional 40-100 ft-lb of tq across the board, with lots available down low.

The SCCA rules for my class (smf) have the following weight restrictions:

1550 minimum weight + 125lbs per liter

Turbo or supercharger adds 1.4l penalty

*cars running 275 or less wide may compete at a minimum weight 200lbs less than their calculated weight.

My goal is 300whp and 200 ft-lb.

Does anybody have weight comparisons for jrsc'd bseries vs k24/20?

Working this out it looks like this:

Bswap (1.8l) = 1550 + (1.8 x 125) = 1775

Bswap (1.8l) + jrsc = 1550 + (1.8 x 125) + (1.4 x 125) = 1950

Kswap (2.4l) = 1550 + (2.4 x 125) = 1850

So I really have to see if the powerband of the jrsc'd bswap is worth 100lbs penalty plus the required (IMO) Lht air to water cooler.

Also, there's the consideration that the kswap might be a lighter overall package (considering it doesn't include the added weight of the blower.

Oh and here's a couple more for ***** and giggles:

Kswap + jrsc = 1550 + (2.4 x 125) + (1.4 x 125) = 2025

K20 swap = 1550 + (2.0 x 125) = 1800

Dart talldeck = 1550 + (2.1 x125) = 1812.5

Of special consideration:
-cost
-powerband
-gearing
-weight (and where it's distributed)
-traction with 275/35/15's
-reliability

Does this look right to you guys?

 

Your numbers look right.. you might want to look into a turbo b16.. if money is no object. you can get the HP numbers you are looking for easily, without the weight penalty of the 1.8 or 2 or 2.4L. Either that or a straight up type-r swap.

B16 + turbo = 1925lbs
B18c5 = 1775

Several of the cars in my region are B16 turbo for that reason.

 

Also, is cost not one of your "special considerations"?

If so, it should also be a deciding factor.

 

Very much so.

Fixed the original post.


Sanimalp, I currently have a c5 in there making 190whp.
I feel like I could use a little more oomph though.

 

I am all about running the lightest car with the biggest tire. Remember FWD is not nice to your front tires. Your front tires like to be treated nice. Figure out how to be nice to them and they will make you happy. (wait am I talking about a car or a woman) HHHMMMMMM.

 

Is this going to be and stay mainly an autocross car? If so, I think the LHT'd JRSC with your existing engine is the way to go.

FWIW, I have a JDM ITR swap and an LHT JRSC setup and mine is primarily a track car, very little autocrossing.

Im still putting things together for the upcoming season so I dont have much to tell you in terms of performance and driveability.

 

Make it time trial legal and you will quit autoxing and get out on the track.

 

*
(Cars running in SMF using tires with a nominal width of 275 or less will NOT receive the weight adjustment as stated in the SM class.)

Just noticed this in the 2012 rule book. I would like to see what a honda in SMF trim that weighs less than 2000lbs with 275 tires looks like. I don't know where all the weight would come from, maybe I'm just missing something.

 

The 200lb weight break does't apply to SMF cars.

A stock ITR motor won't cut it. You need more oontz than that.

How light do you think you can get your car if you pulled out all the stops? From there, figure out the cheapest engine combo that reliably hits your power goals. IMO, you quickly hit a point of diminishing returns once wtq hits 200lb-ft, so all else being equal I would sacrifice some wtq to run at a lighter weight if it were me. (assuming I could hit the lighter weight that is....)

 

I'm going to try and build to the limit of the rules if at all possible.

That being said, 1988 std hatch + k24/k20 head na seems like it would give me the best power to weight. I could gear it to reach 70-75 in 2nd gear on 275 Hoosiers.

Whaddya think?

 

Im not trying to say that you cant do it, and not trying to argue anything, because I think it would be great to hit the minimum weight with that kind of power. Here is what I was thinking as far as the weight goes, and this is mostly rough ideas on weights.
Start out at 1950ish lbs, add 100ish for the motor swap, then factor in that the car is weighed on pizza cutters so the wide rims an tires have got to add 25lbs? for all 4, 15X10, with spacers, again this is just off the top of my head making up numbers that sound fair, numbers could be higher or lower than what I posted. So now your at 2075 lbs, and in smf you can remove back seats, do carbon front end, so you are looking at 50 lbs saved, you can get about 20lbs out in sound material, there is weight to save by switching out the driver and passenger seat. But now your still up 55lbs from where you started at about 2005 and you would want to still loose 205lbs, so if you find another 50 lbs that im not thinking of you would still be 155lbs off from your weight, still very light but not hitting the goal your looking at. Again im just thinking out loud and would love to hear what your thinking as far as weights. My thought is that no matter what engine combo you pick, your going to be off the weight by about the same amount, and if I were doing the same thing, I would opt for the setup that will make the power and cost less, even if it means the cars minimum weight goes up unless you find a way to hit that minium weight.

 

for everyone that says you need more power to run smf, i point you to last years 6th place holder in smf....


this is how it ran in sts form. all he did was swap out to some 13x9 hoosiers, and got 6th. true he's a great driver, but it shows that you don't really need all that power.

 

SO... your saying that with more power the car wouldn't have done any better? I dont think you "need more power" but having a light car that makes 280whp and is about 2000ish pounds is going to give you a edge over a 180hp car at the same weight, driver will play its role as well but anything that puts the odds in your favor is going to be worth it IMO.

 

Ahh touché!

But I'm a mediocre driver and need an extra 100 ft-lb to compensate!

 

sorry missed my point when i posted that.

i meant to point out that, with every turbo charged, k24, b18, super charged, front wheel drive car (which was 18) he ended up in 6th place, and made podium.

true that you do need more power, but im pretty sure if he would have been making 140whp(b16 swap, instead of 100whp stock d16), he would have probably won. the guy in first place had a kswap 93 hatch(making a estimate 240whp if i remember what the owner said), and could only pull a 4 sec lead on him.

this goes to say, op, you don't need that much power. may be down the line when the class DRIVERS get them self sorted out and can drive their high horse power fwd cars, then i would see fit that you should build it to the maximum spec. as of right now, keep the c5, and learn to drive your car.

 

will probably slow you down.

 

Only one way to find out.

Currently I find that coming out of corners in 2nd gear at lower rpm's I am starved for tq , not traction.

Either displacement or boost would help here IMO.

But for purpose of the discussion in this thread, I can't fathom how more power would hurt if building to the class minimum weight requirements.

 

then you need to look at your lines then. how you set your self up for the entry of gate, and the exit of the next.

from experience, i've only had the urge to want more horse power/torque in only a few corners, but that would be inexperience in me finding a good line. i have done ride a longs with people that would take that same corner faster then i would(same class) but take other corners i would take fast, they would take it slow.

and when i mean you would probably be slower is a two fold with the said above about taking a good line.

if you were to not take a good line, that extra hp/tq would ether go up in smoke, or you would have to pedal out of the turn.

 

Wow, ok you presume a lot.

It sounds like to me you are a national level champion.

I don't know what it's like in your region, but in ours (ATL) there are some pretty tight courses and no matter the line I'm invariably stuck at less than 4k rpm in 2nd gear at least a couple times.
It wouldn't make sense to shift to first again and lose time shifting.

But that's beside the point.

The purpose if this thread is to ascertain how to achieve class minimum weight with the best power output.

The subject is driver independent.

Your example of 6th place would be more relevant had he won the class for example.

Beyond that, you seem to think he would've won had he a b16.

Well he didn't and hasn't. Great driver or not.

4 seconds behind the class leader is an eternity.

Would you be happy with 6th place?

I sure as hell wouldn't. (Well at nationals sure!)

The top 4 places in smf for our region are within a second many events, and as you know; any advantage is worth it.

Hell, I've placed first by thousandths of a second.

But if I'm building a car for my class, then I don't want to have to redo it over again.

Keeping the c5 for now would require me to later cut the mounts off the racecar, then weld on the kseries mounts, and of course sell the bswap stuff in order to go K.

 

Im my region courses are designed by the old farts most of the time. They all drive rwd cars, so I get the same thing you are talking about, we end up with slow 180 turns that have no good fwd line, our event sights are smaller so the courses are tight. In the end there are better and worse lines and techniques for the corners but there are some that you come out at 4k or less and just have to power out of, actually thinking about it, there are quite a few. But the low end torque from the JRSC setup will do what your wanting. When I come out of corner at a low rpm I dont think much about it because when I get back on the gas the torque is still there and the car pulls out of the corner.

 

I am also attempting to build a SMF civic to the class limits.

One thing to think about on the weight issue is that there has been talks of raising the minimum weights to encourage non honda makes/models to join the class. the number i have heard being tossed around is roughly 200#.

I am currently running an 89 dx hatch that weighed 2090 on the scales this weekend at the dixie NT.

I have done minimum weight reduction as i have been mainly focused on driving for the past 3 years. My cars minimum weight is 1775.

My plan is also adding either a small turbo or jrsc to my setup now, get some aero r&d and dropping as much weight as possible. Id like to get it down close to 8 to 1 power to weight. thats the goal anyway. as it sits now im at about 14 to 1 pwr/weight.

 

this is just my opinion and suggestion. which is you don't need that much hp, take it for what it's worth. it's your decision, and car after all the fact.

 

90ex,

I'm not sure what that has to do with it, but I've been autoxing with the ARSCCA since 2000.

I enjoy a good debate as much as anyone.
I appreciate your input and perspective.
I do see some bias in your posts though:

I remember people posting things like 'learn on street tires / Azenis' and 'power covers up mistakes' when talking about people getting on course.
I get a similar feeling when reading your posts.

Of course driver is the best upgrade that you can do.
Nobody is debating that point.

The problem with the "make do with the itr swap" mentality is two-fold:
- the swapping to kseries later means downtime and expense in the future
- the swapping to kseries later requires relearning the car

That also means more development and tweaking of the package down the line - when that could be done earlier in the season, with the powertrain in place.
Furthermore, the kswap has a better weight distribution for lhd cars.
Bonus!

I wouldn't recommend someone set up their car (or race) on street tires if they're building for a class that allows race tires.
Learn and setup your car on race tires.
It will handle differently on street tires and you'll be tweaking and relearning all over again if you do it this way.

Now let's look at the 88crxsi in question:
Tom O'Gorman placed 9th of 35 drivers in sts with that car (#77) at nationals.
His score was 137.699.
Andrew Canak placed 1st in sts with a score of 135.428.

That same 88crxsi driven by Mike Snyder placed 6th out of 18 drivers in smf with a score of 134.730.
Brian Karwan placed 1st in smf with a score of 130.131.
(to put it in perspective, the top 3 finishers in smf were all less than a second off).
Dave Hardy placed 2nd (.7 sec off) with a nicely setup 89 ef and dseries+turbo.

It looks like those guys should get together and make that crx an smf car!
Idk the level of prep on that car, but it isn't uncommon to see moton and Penske.
Also, the powerband of a d16 vs a b16 isn't really that much different until after vtec crossover.
A b16 really doesn't give you much of an advantage over a dseries because you're mostly in the midrange at autox.
(I know you know this though.)
I still say a b16 wouldn't have put mr Snyder in 1st place.
It would help some, but not a ton. (Maybe not even a second on that course.)
Now if he had more displacement or boost, then that would give more midrange and help a lot more IMO.

In the years past, there wasn't an smf class and those of us who were swapping motors had to run sm against rwd and awd turbo cars.
I also noticed during those years that the st cars were turning better times than the fwd sm cars in many cases. (jdm coilovers and itr swap anyone?)

Now that smf has been recognized for a couple of years, we are starting to see the development of the cars with the level of prep for the class.
(aka hey some of these guys have moton too! Plus a kswap!)
Of course some guys are still thrown into that class because they cant fit anywhere else.
(ls-v + koni yellows!)
*I honestly can't speak to the level of prep on the smf entrants this past year bc I wasn't there.

 

I think what 90 EX Civic is saying is, until you are driving your car at 100% of it's abilities, adding more power isn't going to make things better. It's simply going to cover for the lack of driving skill.

Aside from that, having too much power can be a hindrance as well.