Going backwards in size

[FieroRacer]

That was something else I may not have mentioned. 1 3/4 primaries are too big for this motor. You won't be anywhere close to the power output needed for that size. 1 5/8 would be a much better idea. 16:1 is way too lean. 12.5:1 is a better starting point for dyno tuning. 14.7:1 is stoich.

I forgot to add headers in my sim. It pulls to 7k now, but def want 1.625 primaries instead of 1.750. Also, you have to account for the exhaust runner from the seat to the end of the port for your primary tube length. I think its about 3" off the top of my head. Been a bit since I measured. Im not sure if the 37.5" I used is optimal or not but I saw 260-270 and 7k peak.

I think you misread my post with the header calculations. You were using the outside diameter, but for calculations it is the inside diameter that is important. The outside diam is pretty fixed in 1/4" increments, but you can get the tubing in different wall thicknesses to come close to the ideal inside diam.

In my spec's I showed 1.75 outside diam with .020 wall thickness. The inside diam, which is what the engine sees, was 1.36. To arrive close to your sim's spec's, I would have to use 2.0 diam tubing and .020 wall thickness (for a 1.61 inside diam - what the engine sees).

I rough measured (measuring tape stuck up an exhaust port) the 2.8 and came up with 2", don't know what the 3100 heads are. But on the 2.8 I showed the ultimate primary length to be 36.5, thus the 34.5 tubing length. Our programs were an inch off from each other.

I have noticed that there are often big differences in the different engine programs around when using the same data. I think that is what we have here. My program wants small diameter, long tube headers. Yours wants larger diam primaries, but also long tube headers (we both used 7000 RPM, it seems). The small difference in length is incidental, but the over 1/4" primary diam is a factor. I will re-run my figures to ensure I didn't miss something.

Thx for the help, BTW

[FieroRacer]

You would just follow what GM did....

Use the same length connecting rod and use a piston with a lower pin hight. To get technical, GM actually went the other way, because they started with the 2.8L then stroked the engine to 3.1L where they kept the same rod length, but moved the pin hight closer to the piston top, to compensate for the longer stroke.

I like you plans so far, basically you will simply be de-stroking a 3100, to make a "2800". It has been talked about, but no one has done it yet to my knowledge, simply because no body so far has been limited by any sanctioning rules that had talked about doing it.
Stroke is just a small part of making power, the more air and fuel you can get through an engine the more power it will make, so your idea is on the right track.

Now, might I suggest a bit of grey area rule exploitation, at least from what you've mentioned it might be worth exploiting.
You say you can't bore the block more than .060" over, what if you used a block with a larger bore to start with? The 3400 block has a 3.62" bore size, which is up from the 3.503 spec bore of the 2.8 and 3.1/3100. Keeping the shorter stroke 2.8L crank, this will give you a "Short Stroke" 3.1L The thing should rev like no tomorrow and make a very good amount of power. I had thought about doing this previously, even had a 2.8L crank to do it, but just didn't get to building it, and I wasn't restricted by any rules, so with DD2K telling me the longer stroke made more torque down low, I've always stuck with the longer stroke. The short stroke 3.1 would require custom pistons. I wasn't overly sucessful in inding any stoke application pistons that would work for me at the time.
I also felt the 2.8 reved a little nicer than the 3.1, but I haven't had a chance to drive a 2.8 with a gen3 top end or a "2800". I believe the rod ratio of the 2.8L is a bit better than the 3.1/3100 anyway.

I like the idea of the 3400, but it mathematically would be illegal. I am allowed .060 over stock, which equates to 3.563 - the stock 3400 is 3.62 or .120 over - - making me illegal. I will HAVE to use the 3100 block, and am not comfortable going more than .040 over FWIW - 3.543.

If I read the quoted post correctly, I could use a 2.8 crank and pistons in the 3100 and it would work OK (because of the correct piston pin location), give me a "2800" engine, and still maintain a good CR? If I were to bore the 3100 to .040 over, get another set of 10.5:1 Wiseco pistons, a CompCam with the same or similar specs as the one in the 2.8 now, and the performance heads and intake setup - - I should have a pretty potent setup?

Since the 2.8 is already built, that will be the one I use. But I could also build a "2800" - - it never hurts to have a "back-up" engine at the track. I just wonder if the "2800" would have any benefit or power gains over the 2.8? I can't see where there would be any, but what do I know?

[FieroRacer]

Another teaser, an autocrosser/road racer at the dragstrip - - they were baffled by slicks on all 4 corners . . .

[SappySE107]

I will have to read the manual again on how it uses the exhaust specs. I didn't spec anything for optimal, but using the same length and going from 1.75 to 1.63 helps slightly.

[FieroRacer]

I have run two different header calculators and they both came to 1/4" of each other on lengths, and were dead on with the diam:
Primary Inside Diameter 1.36 ( 1.36)
Primary Length 34.5 (34.77)
Collector Inside 2.13 ( 2.17)
Collector Length 13.9 (14.53)

[hklvette]

FieroRacer, how were you able to legally run in FP with a Q4? From my understanding (which may be incorrect) of the current rules, engine swaps aren't legal except for XP and mod classes.

I'm planning on running my Fiero in XP with a turbo (and possibly de-stroked) LA1.

Section 17.10.G of the 2010 Solo II rules:
1. The original or a specified alternate cylinder head shall be used.
Any valve guides and valve seats may be used.
2. Compression ratio may be altered by machining, using any head
gasket(s), or elimination of head gasket(s).

The only exception to this rule is in XP, where engine setups are unrestricted.

You would just follow what GM did....

Use the same length connecting rod and use a piston with a lower pin hight. To get technical, GM actually went the other way, because they started with the 2.8L then stroked the engine to 3.1L where they kept the same rod length, but moved the pin hight closer to the piston top, to compensate for the longer stroke.

I like you plans so far, basically you will simply be de-stroking a 3100, to make a "2800". It has been talked about, but no one has done it yet to my knowledge, simply because no body so far has been limited by any sanctioning rules that had talked about doing it.
Stroke is just a small part of making power, the more air and fuel you can get through an engine the more power it will make, so your idea is on the right track.

Now, might I suggest a bit of grey area rule exploitation, at least from what you've mentioned it might be worth exploiting.
You say you can't bore the block more than .060" over, what if you used a block with a larger bore to start with? The 3400 block has a 3.62" bore size, which is up from the 3.503 spec bore of the 2.8 and 3.1/3100. Keeping the shorter stroke 2.8L crank, this will give you a "Short Stroke" 3.1L The thing should rev like no tomorrow and make a very good amount of power. I had thought about doing this previously, even had a 2.8L crank to do it, but just didn't get to building it, and I wasn't restricted by any rules, so with DD2K telling me the longer stroke made more torque down low, I've always stuck with the longer stroke. The short stroke 3.1 would require custom pistons. I wasn't overly sucessful in inding any stoke application pistons that would work for me at the time.
I also felt the 2.8 reved a little nicer than the 3.1, but I haven't had a chance to drive a 2.8 with a gen3 top end or a "2800". I believe the rod ratio of the 2.8L is a bit better than the 3.1/3100 anyway.

Unfortunately, the prepped rules already account for that:

Section 17.10.I.1:
The block may be rebored no more than 0.0472 inches (1.2mm)
over standard. US-produced six-cylinder and eight-cylinder engines
may be rebored no more than 0.060 inches (1.52mm) over
standard. Alternate blocks which are of the same material and
nominal dimensions as standard are allowed. Critical dimensions
for piston engines are deck height, cylinder bore, cylinder spacing,
vee angle, and distance from crank centerline to cam centerline.
Critical dimensions for rotary engines are epitrochoidal curve,
working chamber volume and eccentric shaft location.

so basically, you could use the 3100 block, but have to use the iron heads and 2.8 crank (if they'd fit), unless you changed classes.

Luckily for you, you can shave weight down to 2100lbs and be legal. For some strange reason, class DP (for the 2.5 fieros) requires a min weight of 2625lbs, which the car sometimes doesn't even weigh from the factory! That's the main reason I'm ditching the duke and putting the car on a diet to fit in XP.

[FieroRacer]

Please, before you try to degrade my progress with this engine, let me introduce you to FieroRacer.

First, I will tell you about my Fiero racing experience. I started autocrossing a Fiero in 1989 in an '88 Formula. However in 1992 with the advent of the Miata, the Fiero instantly was not competitive. That's when this particular racecar was born - - and yes - - it had a Rocketparts Quad 4 (the same engine that the Olds Calais were tearing up the track in IMSA). We played with that setup in regional GT2 in Club racing, and in autocrossing in E Mod until 1995.

Neither the car nor the driver were all that competitive in either venue, FWIW - 1900lbs was too heavy and a 267hp, 2.3 liter motor was not powerful enuff to be competitive in E-Mod (1600lbs and at least 400hp was the class norm). Plus a full chassis Fiero that still had the space frame was too heavy and not nimble enuff to play with the tube framed "real" GT cars. But it was still fun to drive.

In 1995 the SCCA did one of it's famous class re-structures, and allowed GT prepped cars to play in the Prepared class. Since the Quad 4 was legal in GT, it also became legal in FP (or AP, depending on which year - the SCCA seemingly re-classed at will during that period). However, in 1999 they did yet another re-structure of Prepared and the Q4 was illegal in Prepared once again, thrust back into the realm of the 1600lb, 400+hp beasts in E Mod.

I interrupt my story to tell where I - as a person - was at that time. In 1999 I was a 2 year member of the Board of Directors in our region, 4 years regional Solo Chair, and the Regional Solo Safety Steward. In 1999 when the SCCA made that last ruling of which I spoke, I resigned all positions with that organization. I failed to renew my SCCA membership after 12 consecutive years, and I joined the growing NASA ranks. Plus I sold this car (which I bought back 8 years later with an iron head 3.1).

I have (from time to time) still autocrossed at the regional level in my Caddy powered daily driver Fiero, first in SM2 and more recently in XM - - but only as a non-member. I have never and doubt that I will ever again rejoin the SCCA, but FWIW my NASA membership is still active - as it has been for the last decade. Now, if my math is still anywhere near accurate, that's 22 years total in Solo and Club racing - - and almost all of that has been in Fieros.

Additional credentials - - - I was a NASA Regional Director for about a year before retiring from my job and moving here, and I also have a pretty good standing in the Fiero community. I formed and was Performance Director of Classic Fiero Owners International (CFOGi) until 2004, and in that role I organized and ran several Fiero track days (Waterford Hills at the 20th reunion was one of them), autocrosses (Wheatstock), and drag races (including two at the Fiero Factory swap meets) all around the country. In 1997 I founded and still moderate the 600+ member Fiero Racing List, and also founded both the Cadero Owners Forum and a Fiero club in the town I used to live in.

With that introduction, I will answer your letter. First, this car will never see SCCA Divisional or National level competition, only local (non-member) runs - - if that. It WILL however see a lot of NASA track and Time Trial events. The only reason I would like to be SCCA legal is that doing so would magnify the target audience significantly if I ever sell this car.

Now for details. You don't seem to have a problem with the 3100 block with 2.8 crank and pistons (.040 over), or 3100 intake (intakes are unrestricted), so I am just focusing on the only thing that you DO seem to have a problem with - the cylinder heads as discussed in 17.10.G - as you quoted. The ONLY wording that would make a "2800" engine questionable is the wording "The original or a specified alternate cylinder head shall be used". Please show me the list of approved "specified alternate cylinder heads", or tell me where I can find such a list . . . .

All that being said, it matters not to me whether the SCCA allows a 2.8 with DIS and aluminum heads (since those were stock in other GM cars in '87 and '88 ) in Prepared or not, but a letter from Howard Duncan says yes, it is OK. The next step to making the "2800" a legal engine for SCCA Prepared is my awaiting a response to a letter sent to the SEB quoting Howard's letter and asking clarification, and then after that petitioning them to broaden that clarification (using their own wording from their response) to allow any 60 degree head to be used as long as it meets the rest of the allowed specs. You know, one step at a time! We'll see what those responses are (you see, I understand how to go about these things from my former affiliation with those folks. Of course the letters aren't in my name because of - - well, let's just say that my name is known . . ).

Now a little about the weight. The car has pretty much always weighed about 1900 - 2000lbs (without driver) even with an iron head 3.1 and a half tank of fuel. I have added a roll cage and replaced the aluminum seats with a little heavier Corbeau FX Pro seats, and a few pounds of ballast in the right front corner (my lightest corner) as a plate under my battery. Which currently brings the car to 2100lbs exactly with 1/2 tank of fuel. So, once again - - legal.

So, in spite of your letter - - at this moment the legality of this engine/car in SCCA Prepared is at best questionable, or to put it another way - pending. But legal or illegal, this is the way it will be built - protests at the local level are unheard of anyway! If we get too much flak from the solo community, this car/engine might end up doing NASA drifting competition (says he with a sh*^ eating grin on his face) in addition to seeing a lot of laps at the new road course just a few miles from my front door, and the new 2.1 mile track being built an hour south of me.

But thank you for your interpretation of the rules and concern for my legality.

[FieroRacer]

A picture of the racecar with the Quad 4 (taken in 1997) and of the "dash" of the Pegasus Motorsports car. The third photo is of the "2800" engine, still in progress. I will send photos of the entire car as soon as I get it back from the shop that is installing and welding the cage. The third photo is of the Caddy powered daily driver at a local SCCA ax last February, just for grins.

The "2800" engine hasn't been installed yet. It started as a stock 2001 engine with bad rods and crank (and badly sludged up with signs of overheating). We rebuilt it using a reground 89 2.8 (DIS aluminum head) cam kit and rods, This photo was taken before the DIS module with Accel Super Coils and the front end from a Fiero (double timing chain with only the alternator and short shaft water pump and pulleys) were installed. We are currently swapping computers and wiring harnesses before installing this engine. After I get the "real" race motor built up with the wild cam, and using the WOT heads and intake as discussed earlier it will be an easy one day swap to replace this motor with the "real" race engine . . .

[hklvette]

FieroRacer,

Thank you for taking the time to reply. I hope I did not sound condescending in my post, as that was not the intent. Not knowing your solo background, I wished to make sure that you were aware of the rules before making modifications, as I have been bitten (in a bad way) by doing just that when I started gutting the interior of my Fiero before I really read over the Solo II rules and realized what class I would be put in. Obviously you have for more experience than I with the rules of SCCA, and I am glad to say that I learned a lot from your posting about what can (and can't) be done to make a competitive and law-abiding Fiero.

Two other things, if I may:
1) You have piqued my interest about NASA racing. Where can I find more information on them?
2) How did you like the Q4 when you were using it? It's been suggested by a member of my region as a powerplant, but i have no first-hand experience with it.

Thanks!
-Henry

[FieroRacer]

NASA has an autocross program in a lot of places, but not all. Here in Colorado for example, there are so many venues to autocross (SCCA, Porsche Club of America - PCA, a couple Corvette Clubs, etc) that the Regional Director here has not started a NASA-X program. Instead they have a NASA drifting competition locally.

What NASA does have is what they call HPDE - High Performance Driving Events. The SCCA has mimicked this program in some places, but being as they try to goop it up with more rules and structure (like they have a habit of doing) it just isn't the same. HPDE is a program that is one step beyond lapping days or track days. It follows what is commonly called "gentleman's racing" rules, passing only in specified straights, etc. And you can play with anything on four wheels (except open wheel cars) out there, with about the same safety tech and dress rules - helmet, hard sole shoes, etc. If you and your car can autocross, then it will HPDE! No classing to contend with , no "you can't run an '88 cradle in an '85 Fiero - even though they are on the same line - because you have to drill a hole" type mentality to put up with.

NASA - in every venue of motorsports they are involved in - is more relaxed, more "fun" oriented than "rule" oriented (unlike the SCCA, which is the opposite). Research them at http://www.nasaproracing.com/

The Quad 4 was the first of many multi-valve 4 cylinder engines, very "primitive", loud, rough - but fast (for it's time). The beauty of this powerplant is that it was light and could easily produce more than 100hp per liter. In the road racing version it produced 270hp+ from 2.3L. What it didn't have is a lot of torque, and being a multi-valve engine it required a lot of RPM, the power curve came on at around 3000RPM and wrapped to about 6500RPM where it dropped off. (I de-tuned my Rocketparts engine to 237hp which brought the torque up to 208 by doing so. Adding torque - even at the expense of horsepower - made the engine more drivable between the cones. (In autocross, torque is more useful than horsepower, as I am sure you know).

When we were putting this car together initially in the early 90's, the Olds Calais was killing cars in it's class with the Rocketparts Quad 4. We had the Fiero stripped to just over 1900lbs with this engine and a full 6 point cage (the Q4 long block was less than 200lbs). And that made the car very fun to drive - but not competitive in E-Mod. You are looking at the likes of Tamandli's 1600lb tube frame, Rover racing V8 powered Fiero, or Turners 1600lb tube framed 600hp/600lbft Triumph TR8, or more recently his JDM racing rotary powered 1600lb Miata for competition. The Q4 was fun to drive - yes. But competitive in E-Mod?? Not hardly. That's why when it became illegal in Prepared for the 2000 season I moved on. So I guess I would need to know more about what you want to do with your car, such things as whether it will be a dual purpose (street and weekend racer) Fiero, or just how you plan to use it. But keep in mind that my current choice for a powerplant is NOT the Q4 but the more torquey 60 degree V6 . . .

I would also suggest you join the Fiero Racing List@yahoogroups.com and get their feedback and suggestions - - - there is a lot of talent on that list! And if you would care to, send me a PM telling me where you are located and I will see if I know anybody near you in either the Fiero or the racing community - - or possibly even both??