STL engine builds?

[TomL]

Intentional, to keep STL from poaching away ITS drivers. It was a double-dipper "gimme", not an intended performance evaluation.

GA

Huh?? As Ron noted above (and has been noted many times previously), setting the RX7 weights at their IT level makes little sense given the STL philosophy - basically "IT-with-engine-mods". All the non-rotaries get more horsepower from cams and compression and many of them get weight reductions, while the rotaries get -- absolutely nothing. Based on your 12lb/whp baseline, the ITS RX7 ought to come in at maybe 2160 and the ITA RX7 at around 1560 (!!). Plus RWD adder, of course. So the rotaries are at an absurdly high weight if the stated philosophy were being followed. (2680 vs 2225 for 13b and 2280 vs 1600 for 12a.)

But of course it isn't. But the "keep STL from poaching ITS" rationale is laughable. Considering practically every STL eligible car is an ITS (or A or , why is it necessary to give RX7s such "special" consideration? Is any one worried about poaching Miatas (or CRXs or Integras) from ITS or ITA? It seems the real reason is that, for whatever reason, some people don't want rotaries in their class (except as IT level field-fillers). If that's so, why not just be honest and allow them in as IT cars along with the SMs and be done with it, instead of pretending they are being admitted to the class on the same basis as other cars?

Or am I supposed to be thankful that the request to increase the weight of the rotaries got turned down?

[Andy Bettencourt]

So Tom, we have to realize (even though I am not sure where it's printed) that this is a piston-based class. The rotories were allowed in to fill fields and give racers a place to try a National class (even though STU already allowed that). They were weighted intentionally high so as not to become competitive. We have to accept that is the direction of the class and not try and force the rules to 'make sense' - meaning they are in there on a peripheral basis so we have to keep that in mind.

The larger fear is that if you set the weight properly (at the 1.8 weight) for the 13B, it will find it's way into a Miata and dominate. Remember, conceptually, this is a FWD piston-based engine swap class with parameters to allow other platforms with penalties.

[TomL]

OK, I'd never seen that stated as a criterion, but if it is why wasn't that stated up front. The assigned weight makes it clear that it was intended that rotaries were not to be competitive (as I was complaining about, obviously). But my question is, "why shouldn't the rotaries be classed on a competitive basis?" Or put another way, if someone puts a 13b into a Miata (classed at the same lb/hp as any piston engine) and wins, what is the problem? Or is this the same problem that there was with putting Mustangs and Camaros in IT - there's no rational basis, it just "doesn't look right"?

[TomL]

Greg, obviously the rotaries can play in STU, but with the rules as written, the cost of building a proper STU car is substantial (dare I say ridiculous?), since you get totally redesign the suspension, do major body mods, etc., in addition to developing the engine.

I'd be interested in running STL with an upgraded engine in an IT-level chassis, just like anyone else gets to do. No major expense beyond the engine upgrades, and I can be reasonably competitive. (Yes, I know that engine development is expensive if I want to win Nationals, but I can get 90-95% of the way there for not much money). I could understand keeping rotaries out if they would produce significantly more HP than a 2 liter piston engine, but that isn't the case - a street port 13b shouldn't make much if any more than a good 2.0 liter. If that's the case, I ask again, what reason is there for not assigning the rotaries a weight that is the same as for a piston engine of the same power? Or is in fact there no reason beyond, "it doesn't look right". (or "this is a piston engine class", even if we never said so)

[Andy Bettencourt]

OK, I'd never seen that stated as a criterion, but if it is why wasn't that stated up front. The assigned weight makes it clear that it was intended that rotaries were not to be competitive (as I was complaining about, obviously). But my question is, "why shouldn't the rotaries be classed on a competitive basis?" Or put another way, if someone puts a 13b into a Miata (classed at the same lb/hp as any piston engine) and wins, what is the problem? Or is this the same problem that there was with putting Mustangs and Camaros in IT - there's no rational basis, it just "doesn't look right"?

Well some of us have been preaching that if this class is to succeed, it needs far more diversity. The IT (internally unmodified) 13B in well-tuned preparation will churn out 180whp. That is WELL within the 1.8L weight and HP targets. Why they won't allow it? No real good answer has been forthcoming and frankly I can't think of one.

Look at STL like this and you'll be a lot happier: It's NASA Honda Challenge by SCCA with some provisions for other cars to compete in a peripheral fashion. Seriously, it's a piston-based swap class conceived for FWD, and compensated for RWD.

[Rabbit07]

I am not trying to contradict Greg here, but the way I remember the 13b getting classed was this. A couple of STAC committee members have personally seen 13b RX7s making around 181 whp. Our bogey in STL is 100hp per liter. A 2.0 liter with 200 crank should be around 170-180whp. The 13b was set at the 2.0l weight plus the RWD adder. Anyone that feels this weight is in appropriate please send some data and a letter and we will look at it. I actually think that either an RX7 or Miata with a 13b in STL will be competitive.

[TomL]

Thanks Andy. And I'll take your advice and just forget the whole thing.

If I may ask, is this coming from the CRB (or BOD) or from the STAC?

[Andy Bettencourt]

Thanks Andy. And I'll take your advice and just forget the whole thing.

If I may ask, is this coming from the CRB (or BOD) or from the STAC?

It's coming from me. Just read the threads on this board and others and form your own opinion. I have NOTHING to do with this class if you thought I did.

Chris: 181whp is pretty damn close to your 100hp/L target at the 1.8L weight. Why assign it the 2.0L weight? (forgetting for a second that somewhere it is written this is a piston-based class). Besides, IT-built 1.8L GSR Teg motors are already at that target - BEFORE additional STL prep allowances. The HondAcura powerplant clearly exceeds the target yet the 13B is saddled into no-mans land.

Wait, are the class targets based on WHP or crank HP? Has to be WHP or else the Teg is around 120hp/liter at the crank assuming 185whp on the light side.

[Rabbit07]

The numbers are Crank.

On the Honda's remember the cam lift limits. The GSR is close even stock and the K20 is over the Limit. This was intentional.

It is impossible to see every possible combination that could come out of this. What really ticks me off is all the negitive talk about how it's a Honda class, and it's a FWD class. I am seriously looking at building a 99 Miata for STL. I see no reason why this car couldn't run with Greg's GSR. I still think a DOHC Neon can make the power needed to compete. I also like the M42 BMW, but don't want to build an E30 (too old).

[Ron Earp]

Well some of us have been preaching that if this class is to succeed, it needs far more diversity. The IT (internally unmodified) 13B in well-tuned preparation will churn out 180whp. That is WELL within the 1.8L weight and HP targets. Why they won't allow it? No real good answer has been forthcoming and frankly I can't think of one.

I too think it needs diversity. I think there was great opportunity to have a multi-marquee class with higher than IT-prep sans the crazy Prod crap. But various rules such as the displacement cap and no model for various engine architectures, coupled with the age limits and the SCCA's obsession with over/under classes and a seemingly chassis/engine bias mean the class is predominantly a import FWD fest.

Look at STL like this and you'll be a lot happier: It's NASA Honda Challenge by SCCA with some provisions for other cars to compete in a peripheral fashion. Seriously, it's a piston-based swap class conceived for FWD, and compensated for RWD.

Thank you. I now understand.

[Greg Amy]

All the non-rotaries get more horsepower from cams and compression and many of them get weight reductions, while the rotaries get -- absolutely nothing.

You're mistaken, Tom. The 12A and 13B get to "Street Port" (same exact mods as in E Prod), at which point they're fully compliant to run in STU. If you want to weight less and more mods, we very much encourage the 12A and 13B to come play in STU.

Modified rotaries have pretty much zero chance of playing in STL at either a lesser weight or with mods (please read my signature below). If you still think that's laughable, feel free to make a request to the CRB that they strike the rotaries entirely from the STL allowances (you wouldn't be the first.)

GA

[R2 Racing]

By my calculations which could be wrong, would put me at ~195 whp which would seem to be pretty difficult within the rules for my specific motor(my choice to use it I know).

2340/195 = 1 HP to 12 LBs

I have seen a lot of non VTEC 1.8 B18 motor dynos and build outs and that seems like a difficult number to hit with a 10/10ths build.

The Integra B18s are reportedly hitting high 130s whp in IT trim, and that's before the cams and compression allowed in ST...they've left almost another point-and-a-half compression, and a good bit of lift and duration, on the table.

I need to try to find these IT B18A/B1 specs to see how they are making the power and go from there. I looked at the Ruck ITA integra end it says 150 hp I just dont want to assume whp.

Why don't you guys just ask? 150whp for an ITA Integra (B18A1/B1) has kinda been "the norm number" for years. "High 130s whp" would be dog meat at their 2600lb weights.

I have no idea what the B18A1/B1 is allowed to do in STL, but my FP B18A1 most certainly doesn't make 195whp. That's a 11.5:1 compression and .450 valve lift build, with a stand-alone ECU, IT port matching and intake manifold rules, pimpy exhaust, cold air intake, .040" overbore, balance, blahblahblah. I have started on a brand new FP B18A1 build for 2012, which I do expect to be better than my current one, but still ain't gonna be 195whp! I'd bet that's possible with the B18C1, but that engine also isn't going to make near the torque of the B18A1/B1. That'll be your tradeoff. I'd expect about a 15-20whp difference between the two, but probably a 15-20wtq swing too, but in the opposite direction.

[R2 Racing]

I have no idea what the B18A1/B1 is allowed to do in STL, but my FP B18A1 most certainly doesn't make 195whp. That's a 11.5:1 compression and .450 valve lift build, with a stand-alone ECU, IT port matching and intake manifold rules, pimpy exhaust, cold air intake, .040" overbore, balance, blahblahblah.

I don't know why I typed 11.5:1, as that's incorrect. The FP classification is 12.0:1.

The Honda 1,8L B18B1 (single-cam engine) won't make as much power as the Honda 1,8L B18C1 (dual cam)? Shocked, I am.

You're so not a Honda guy....

These are all 1.8L, DOHC engines:
B18A1 - non-VTEC, and produced from 90-93.
B18B1 - exact same as a B18A1, but produced from 94-01 with a little more exhaust lift, 1mm bigger throttle bore, OBD2, and +2hp & +3tq.
B18C1 - the "GSR" VTEC version, with +30hp over the B18A1/B1.

[coreyehcx]

I don't know why I typed 11.5:1, as that's incorrect. The FP classification is 12.0:1.

So where are you at with that setup? (Im guessing 170 based off your site)

STL is at 11.0:1, .425 lift, port matching/gasket but no additional mods to the intake. So I would assume those increases alone would produce pretty decent power on a b18a/b1 with that type of compression and lift for FP.

I would have thought you could be at the 200+ mark with the allowances in FP but I guess not.


b18b1 had different fuel maps on the factory tune as well to help produce the additional power .



I just thought about the bastard rare b17a1 vtec motor. edit: i saw what i was looking for on this.

[mossaidis]

^ b17a1 I *think* hits the sweet weight min spot for my EG. Rare is an understatement.

[Greg Amy]

You're so not a Honda guy....

Thanks for the schoolin'.

Greg, how is your setup coming along?

I'm not planning on any engine changes this coming year, built too many this last year. Might work on a better intake/exhaust but the focus is to get the car down to its minimum weight, work on chassis and aero, and qualify to attend the 2012 Runoffs.

^ b17a1 I *think* hits the sweet weight min spot for my EG. Rare is an understatement.

2210# min weight, 160/117 hp/tq stock. Probably a revver? Can it be built from scratch from common other Honda parts?

Then again, the B16A2(?) from the Civic is 160/111 hp/tq stock, more readily available, DEFINITELY a revver, and you can weigh 130 pounds less... (back me up on my data there, "Honda guy"... )

GA

[coreyehcx]

Rod stroke ratio is 1.63 on the b17a1, 9.7:1 compression compared to the b16a2's 1.75 r/s and 10.2:1 comp so it should stand to gain more by getting to the 11.0:1 limit. The revving is going to be similar with the allowances on the motors and the r/s ratio still keeps it in the spinner zone.

The heads are pretty much identical with the same pr3 cast and it has all the lego compatibilities as the whole B series family.

It would be a very interesting choice, they only made I think 5k total 92-93 gsr's so sourcing these engines is a problem and they have a higher premium because of it.

It is not impossible to source a short block, get a pr3 usdm head and go to town.

Is it worth it over the b16? Probably not once the additional weight is added for the extra 100cc's. I have not seen very many b17a1 builds over the years so Im not really sure what they are capable of, they could possibly be a decent option for this at the weight given.

[R2 Racing]

So where are you at with that setup? (Im guessing 170 based off your site)

STL is at 11.0:1, .425 lift, port matching/gasket but no additional mods to the intake. So I would assume those increases alone would produce pretty decent power on a b18a/b1 with that type of compression and lift for FP.

I would have thought you could be at the 200+ mark with the allowances in FP but I guess not.

More than 170whp, no where near 200whp. The highest output all-motor B18 I've ever built was a JDM ITR B18C engine, with CTR pistons and shaving for ~13.0:1, leaded race gas, complete aftermarket intake manifold, Hondata S300, pimpy exhaust, a huge, lumpy cam, and a valvetrain that let it rev to the moon. It did 201whp.

2210# min weight, 160/117 hp/tq stock. Probably a revver? Can it be built from scratch from common other Honda parts?

Then again, the B16A2(?) from the Civic is 160/111 hp/tq stock, more readily available, DEFINITELY a revver, and you can weigh 130 pounds less... (back me up on my data there, "Honda guy"... )

GA

Corey & Chip got it. If I could reach minimum weight for the B16, I'd pick it. If not, go with the B17. Yes, the B17 is real tough to find.

Jake - saying the B16 & B17 heads are "ITR heads" isn't exactly right. The molds are very similar, to say that they do indeed flow well, but they don't have the machining done to them that the ITR head does. The GSR B18C1 head is the "bastard child" of them all, with a totally different manifold bolt pattern and worse flow.