STL engine builds?

[coreyehcx]

I was curious if anyone has completed an actual STL vehicle specifically built for the class?

I'm finishing up my own and I'm curious to see what type of power some of these engines will be making. I hope to dyno mine at some point in the next few months (b18b/civic) ans was looking for something to compare to.

Thanks

[Greg Amy]

I don't think there's any 10/10ths builds out there yet. But when/if STL goes National the floodgates will open!

I think our target (I'll have to check) for whp/wt is right around 12, so if you're around there you're in the ballpark (and don't hold me to that number as a hard fact). Generally speaking, the larger-displacement cars will not be able to take advantage of the cam lift and compression ratio rules as much as the smaller ones can, so that should help a lot. - GA

[TStiles]

Here's some insight in regard to where the miata guys think they will come in :

http://mazdaracers.com/topic/201-miata-stl-builds/

[Mrsideways]

The car I want to build on paper says about 200-210whp and 2340lbs mid engine. But I have a STU car so it's just bench racing.

[coreyehcx]

Thanks Greg,

I'm not holding you to anything because I know its changing all the time.

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.

I'm assuming my current build is probably around a 160ish whp. I guess 190 is possible and I wont know until I dyno my own build which is probably a 6 or 7/10ths build.


Thanks guys for the additional posts I just saw. I'm just trying to see where people might be at to see if I need to go the distance on the few things I skimped out on. I'm new to club racing and look forward to it all in 2012.

The things I didn't have done were gasket matching, overbore, blueprint and balance, and left a little on the table in terms of lift @ .423, .413.

This is a dynojet from an almost identical build as mine except I have a better header, compression ratio is 9.2:1 and mine should be right at 11.0:1 limit.




I'm just looking for help/knowledge, I'm not trying to start a debate or an argument about engine allowances or anything.

Thanks again.

[Greg Amy]

What B18 engine are you building? Maybe the Integra B18A1/A2 from the Integra? That dyno chart shows "B18A", which is a Japan-only engine, not really related to the US-market B18s...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'm running the B18C1 (Integra GSR engine) and I'm hoping to hit that 195hp number; any twin-cam head should get pretty close.

[coreyehcx]

B18B1, I tested it for the first time at Roebling this past weekend so its finished for the most part. I'm assuming that's what they tested (B18A1) and if not the differences between motors are .2 in compression between USDM/JDM. Those motors are identical outside of that so they are related just like a JDM B18C-non R and a USDM B18C1.

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.

Going from 130ish to 195 is a pretty big jump from cams and a point and a half of compression. I can see it happening with a ported head on the B18B1 since the airflow for that head is pretty dismal.

I wouldn't imagine you plan on discussing how you plan to hit those numbers with the B18C1?

[Greg Amy]

Ah, but head porting is not allowed in ST Light...

The B18C1 is reportedly making 175-ish whp in ITS trim, and it has another half-point of compression and some cam tuning to go (but not much in the intake lift; that's already at .423"). The nice thing about when we ran that engine in ITS was that I noticed the thing would pull all the way up to redline, and feel like it wanted to go more. So we'll throw valve springs and retainers to take advantage of that, do the overbore, add some compression, do some cam tuning on duration (and add lift on the exhaust), use adjustable cam gears, windage the bottom end, and stick the intake some place where it's very, very cool...tune the Hondata to sweeten the pot and couple it to Type R gears and a numerically-high final drive I think we can get there.

All it takes is time and money, right...?

GA

[coreyehcx]

Definitely, time and money in the development is probably where a decent amount of power is hiding. I made very good power with a B18C1 I built just as a track day vehicle.

I see that motor (B18C1) being able to get there, I'm just having doubts on my selection after seeing these numbers for whp/wt.

I know there are some extra little things I can do here and there outside of oversized pistons etc. I guess if I cant get it close, I could always use most parts and swap them over to the VTEC motor that fit.

I'm really over thinking this, I could have a 10/10ths build and not be competitive due to my own abilities lol.


Thanks for this, pretty good thread.

Here's some insight in regard to where the miata guys think they will come in :

http://mazdaracers.com/topic/201-miata-stl-builds/

[shwah]

I'm running the B18C1 (Integra GSR engine) and I'm hoping to hit that 195hp number; any twin-cam head should get pretty close.

No VW group motor will. Not without porting, or allowing non US market NA 20v motors.

[Chip42]

"L/LU" suffix (mid 80's to early/mid 90's era) toyotas won't either. but the non USDM ship has sailed, apparently.

Corey, we've talked offline, but I think there's a lot of small change you can pull together on that B18B, and if you decide to go balls out on it that small stuff would add up to a pretty good gain. likely not as much as a good header over a crap one, but gains. and there's the real consideration that most "known gains" are from all out drag / drift type unrestricted builds or some kid with a new cam, a blowmolded case of sockets and a camera who swears up and down that he's only seeing 3hp, yo. either way, the formulae we deal with in IT and ST are restrictive in ways that traditional engine builder logic is still seemingly oblivious to. doesn't make the knowledge wrong, but it doesn't make it right, either.

your car runs well, and there's a lot left in the package - from the loose nut to the tires. develop that and build in iterations.

[coreyehcx]

I need to go get it dynoed and go from there.

The motor feels good, maybe it makes more power than my estimate.

I have a few small cheap items I can do to generate some additional power too on top of what we discussed.

[Rabbit07]

I wanted so badly to get Non-USDM Engines in ST, but the CRB would not have it. Actually I think that everyone on the STAC wanted Non-USDM engines. We'll keep trying, but I worry that we need a huge change of the guard on that one.

Happy Racing

[coreyehcx]

In my case by using a jdm head increases airflow by about 29 cfm putting it just a little behind a B16 head.

[lateapex911]

I keep thinking about STL, and the relatively small number of car/engine combinations that could yield really competitive fruit. Seems everything I think of (other than the known core cars like the CRX, Integra, etc) has a "gotcha".
I'm not a Prod guy...I still have a distrust of the 'system' and the abuses it's shown over the years, and the all the whining of the Prod guys over their world and crap has soured me. So that's not a National racing path for many.
ST is objective, and that's similar to IT, which I helped get rolling in that direction. It's new, fresh thinking (well, in a National category), and has an approachable (sort of!) ruleset.

But finding a RWD car that could be competitive, even as a thought experiment, has proved impossible.
My latest "Hmmmm, I wonder?" idea:

The new Subaru or Toyota BRZ/ FRS thing. 2.0 litres, 170-ish hp stock, RWD, and it looks like a good basic platform.

OK, the $$ aspect is nuts, but assuming wrecks become available in a year or so (or less, LOL), what could that engine make? Are my calcs right that it would currently weigh 2665?
I KNOW theres some "gotcha" that will make this car unacceptable, LOL. What am I missing/

[Ron Earp]

I
OK, the $$ aspect is nuts, but assuming wrecks become available in a year or so (or less, LOL), what could that engine make? Are my calcs right that it would currently weigh 2665?
I KNOW theres some "gotcha" that will make this car unacceptable, LOL. What am I missing/

Seems heavy compared to the uber-Hondas.

Why does the RX7 weigh the same as it does in ITS trim, 2680 lbs? That seems mighty heavy for a 180 rwhp car with a horsepower curve resembling more of a spike than a curve.

[Greg Amy]

Seems heavy compared to the uber-Hondas.

Same exact weight as any other allowed 2L RWD Honda...

Why does the RX7 weigh the same as it does in ITS trim, 2680 lbs?

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

GA

[lateapex911]

Same exact weight as any other allowed 2L RWD Honda...


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

GA

So, are you inferring that the Toyobaru won't be allowed???

[Greg Amy]

So, are you [implying] that the Toyobaru won't be allowed???

I cannot imagine how you inferred that. Methinks you're degrading to the "black helicopter" side...

[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?