Circle Track 3.1L (Modded)

[sharkey]

the 2.0" exaust is a real killer, most 60*v6 engines came with bigger than that from factory.

i wouldnt rule out a dohc swap. with minor tweaking well over 225hp is possible, so it would be worth it even with the 100lb weight penlty. even if you did go with a pushrod motor, how much do they enforce the rules??? you could do the 3400 with camaro 8cc pistons and have 12.7:1 compression, but are they going to tear the motor down for inspection???

the rules seem very open to interpertation. now it says the tranny and converter must be stock, but is that stock as in no modified, or stock as in came in the vehicle??? if you can, id run a th125 and a factory 2950 stall converter. didnt come stock in that car, but all oem stuff. the 125 would save a bit on weight and rotating mass. you could run an obd1 harness and ecm for a 5 speed, and burn chips for it.

[ForcedFirebird]

We show them the same kindness now...but no one ever links to them anyway cause they have nothing worth looking at.

I go there mainly because there are some knowledgeable forced guys, even thought they are on 90* motors. I was going to PM community to get him here anyways, but he found you . I think it's crap that you can't post links to "unsponsored" sites, they just want to get your money Ben, LMAO.

I also like that even though you sell your service, you don't keep secrets and we can all benefit form eachother

[SappySE107]

We show them the same kindness now...but no one ever links to them anyway cause they have nothing worth looking at.

We can certainly set you up with a stock appearing motor other than the plenum will be larger than stock. Get the blank upper off a 3400 from 96-99. Some cars got them, some got 3400 on them. There is a rare car with a 3100 labeled large port plenum that uses the 94-99 EGR. 3100 mpfi posted it, and I forget what it was now.

First main issue is your ECM. It has to go. Wire it up for OBD2, or wire it up for memcal OBD1. 94-95 3100 ecm is not programmable and will make any real effort of power a waste of time and money. Depending on your dependency to that vehicle, it may be easier to get a newer vehicle.

For what you are doing, I wouldn't decline on the DOHC. 94 DOHC is tunable if you swap the wiring harness. Will love higher revs and has a better powerband for circle track than a 3100. You can leave it stock appearing, change the cam timing (not keyed so you can time it however you want, meaning you can tweak your powerband for the track with the right tools). Use thicker oil and it should be good. You can go with lighter lifters, as I doubt those would be inspected and if they were, you would have to know that stock weighs more to notice. There is a performance belt from cloyes now, though no one here has it yet that I know of, or at least used it for any length of time to determine its worth.

Get a trans cooler. Overfill the trans 2 quarts. Use type F fluid. Im not sure what trans mods you can do but if you can modify it, shim the accumulators and install the shift kit. Possibly more, dunno budget.

If you want to stick with the pushrod, we can make it good but porting the manifolds would be trick. Acid porting maybe? Never done it as I don't have to follow rules for street cars.

Wanna go crazy? 3.4 DOHC pistons, 3500 heads, 3400 engine. on a .040 overbore I measured 12.4:1 compression using the 96-97 pistons.

[ForcedFirebird]

The link was also to here for the plenum for sale in the buy/sell/trade section. I can't believe they edited out all links to this site when they only have people with limited knowledge on the 60* motors. Come on, they are still convinced that the 3500 heads will fit a 3.1/2.8 bore and Ben (SappySE107) has the pics on here to prove it, who BTW runs the site and the store.

[ForcedFirebird]

Glad to see you made it over here . And you even quoted me with stuff I learned here
EDIT : The FWD pistons was meant to 26.4, not 24cc. You can find that info on the CRCalculator located in the left sidebar.

[communityracingchallenge]

1994

[SappySE107]

What year grand prix?

[communityracingchallenge]

First off.. Since this is my first post after lurking for a little while.. I thought I'd do a real quick intro. My name is Patrick, some of you might have responded to a similar thread I had at another GM V6 site, but since this sites seems so much more active, I thought I'd post here also.

Since what I'm wanting to do is modify a 3.1, I thought I'd put this thread here... I hope this is the right place.

I race a 3.1L Grand Prix on Friday Nights at Spartan Speedway in Lansing, Mi and on Saturday Nights at Springport Motor Speedway in Springport, MI. Both are oval tracks.. SS is 1/4 mile while SMS is a 3/8 mile.

Its the the Pure Stock Class at both tracks. This class of racing puts V-8 RWD cars and V-6 FWD cars on the track at the same time and against each other. The rules severely limit the performance modifications you can "legally" make to the cars and good V-6 run very competitively versus the V-8s.

I'm hoping to find some GM V6 Experts who will help me dial these cars in so we can start running up front. Currently, I'm getting killed by V6 Dodges and V6 Fords (SHO) and all the V8 Chevy's.

I get in, thru, and out of the corners better then the V8s do, but I'm getting absolutely crushed on the straights.. more then I can make up on the corners... especially as the car first comes out of the corner, there is just no get up and go. Versus the other V6's, they get through the corner as well as I do, and leave me on the straights.

The track "rules" are posted at the very end of the thread, but I'll tell you know, I don't really care what they say. Racing is full of Pirates, so consider them more like "guidelines" and until I'm running in the Top 3, no one is going to care anyhow. In other words, I'm going all out till somebody makes me start taking stuff off.

I have gotten a couple of suggestions so far:

3500 heads w/ exhaust mani, modified 3500 lower intake mani and a slightly ported 3400 intake plenum will look exactly like a stock motor if your given the open hood inspection. that little combo will juice you up for sure

and some better more detailed advice:

The 3400 heads on a FWD 3.1 will net the same compression since the FWD pistons have a dish yielding 24cc (if they are aluminum heads). If you go to RWD F-Body/Camero (12cc) the compression will be 11.74:1 (with .060 gaskets).

I didn't read the rules word for word, but in the engine catagory it didn't say anything about a re-ground cam ,available on non-roller lifters (adjustable rockers) only.

Circletrack, you didn't specify the year for your engine but I'm guessing you already have aluminum heads?

Note the 3500 plenum flows far better than the 3400. And the 3400 heads ported will outflow the 3500 heads unless you use custom gaskets since the 3500 aftermarket is close to nill at the moment.

Make sure the heads you get are 170 or 487 casting numbers, they have larger valves and ports and the LIM to match. They came on some earlier 3400's, and all 3400/3100 after '99 IIRC. Use the TB/plennum from a 3500, the CAMARO pistons.

The heads you can come by if you watch on ebay, I got a set for $25 (shipping was $40,lol) and was the only bidder. Just look for the casting numbers I gave you.

I think you will need to get the matching exhaust manifolds to take advantage of the D shaped ports

At least one person has suggested I just take the 3.1 out and replace it with a 3500. Another suggested a 3400 (not a 3.4 DOHC).

SO.. Do you guys agree ? Do you have more suggestions ?? What would you do ???

The mid-season championships are next weekend and July 7th starts the 2nd half, I'd sure like to get off on the right foot for the last 10 races.

Thanks in advance.

Patrick

--- Track GUIDELINES ---

SECTION 17
PURE STOCK (FWD) RULES

A. BODY AND CHASSIS
B. ENGINES
C. DRIVE TRAIN COMPONENTS
D. BRAKES
E. SAFETY


--------------------------------------------------------------------------------


Notice # 1: The Pure Stock division is new for the 2006 season. It was added in an attempt to provide a more affordable option to racing. Due to the many makes and models available for use, restrictions and minor changes may need to take place during the season as we learn more about this new division.

Notice #2: Any interpretations of the rules are left to the officials, whose decisions are final. Just because it is not written, does not mean you can do it. The two words to remember in this class are STOCK ONLY. In the event a car is deemed to have illegal parts the car is subject to being banned from all future race events at Spartan and Springport Motor Speedways. The driver is subject to loss of points to date, all prize money for the night and suspension from property.

Notice #3: If you are considering building or purchasing a Pure Stock we highly recommend you receive pre-registration approval prior to doing so. There may be cars that have been permanently suspended Spartan because of rule infractions.

A. BODY AND CHASSIS:

Any American made FWD V-6 model (no convertibles, 2 seat coupes, super charged or turbo).
The vehicle must remain in its original form. No alterations are allowed unless specifically stated in these rules. (See notice #3)

a) Wheel base minimum: 104.5"
(NOTE: Small-bodied cars not allowed. If you're unsure, call first)

b) Weights: (post race with driver) 3000 lbs.
(3800, DOHC, multi-valve add 100 lbs.)

c) Bumpers must be stock appearing.

d) Tow hooks are required.

e) All doors must be welded shut.

f) Rub rails are allowed (no sharp edges).

g) Must be able to open trunk and hood without use of special tools. Hood pins required.

h) Rear and side glass must be removed. Windshield may stay or be replaced with 1/8" thick Lexan. All other glass must be removed including but not limited to taillights, headlights, turn signals, mirrors, plastic, upholstery, carpet, etc.

i) Any after market add ons must be removed. Ex: trailer hitch

j) The battery may remain in the original factory location provided it is in a safe location and securely mounted. If the battery is relocated, it may only be relocated to the trunk area. Batteries mounted in trunk must be secured by (2) two 1" metal straps. No batteries mounted in driver's compartment.

k) Fuel tank to be mounted in trunk and secured with (2) two 1" metal straps (made for racing for fuel cells are recommended). May run plastic gas tank if it is located in front of rear axle, under floor pan and is fully covered with a steel skid plate. Fuel lines must run below floor pan. Tanks that are mounted in the trunk must have protective hoop and 10" of ground clearance.

l) Front fender inner liners may be removed.

m) No frame alterations of any kind allowed.

n) No adjustable shocks or struts of any kind allowed.

o) Must have stock floor plan to rear axle and all holes in fire walls must be covered with sheetmetal.

p) Must have battery kill switch mounted on "A" pillar.


B. ENGINES:
a) Stock only in stock location. No aftermarket parts.
b) Single exhaust only. Maximum 2.0" OD. Last 6" of exhaust must exit behind driver and be fully visible. No exhaust leaks allowed.


C. DRIVE TRAIN COMPONENTS:
a) Stock automatic only. Cooler are allowed.
b) Stock diameter working torque converter only.

c) No aluminum wheels. Steel wheels only, stock for that year, make and model.

d) 1" Lug nuts are required.

e) D.O.T. Street radials only. No bias ply, made for racing tires. Maximum width 235. No less than 60 series (no 55, 50, 40). Minimum tread wear rating of 300. All 4 tires and wheels must be the same size.


D. BRAKES:
a) Must have 4 wheel hydraulic brakes in working order.

E. SAFETY:
a) A four point cage with four driver's side door bars, three right side door bars and a 1/8" steel plate on driver's side door bars from front upright to rear upright and from top door bar to frame rail is mandatory. A front hoop may extend into the engine bay area. Tubing must be .095 gauge, 1.75" O.D. and must be padded around driver.
b) Made for racing aluminum seat, properly mounted is required.

c) Quick release five (5) point safety belt with three (3) inch minimum belt width harness securely mounted to roll cage is mandatory. The belts must also contain the original certified date tag and must be less than 3 years old.

d) Driver's side window net with quick release is required.

e) A 2 lb. currently dated B or C type dry chemical fire extinguisher is required within driver's reach.

f) Fuel injected vehicles are required to have fuel pumps wired to stop any fuel from being pumped when engine is not running.

g) Steering wheel center must be padded. Quick release steering wheel optional.

h) Refer to section 4 for additional safety requirements.