engine specs

[keithcar72]

I am starting to build a 2.8 iron head motor. This is a street legal race motor. this motor will see little to no actual street time. It will be run under a couple of different sets of rules. so it will have to be a 2.8, however I will be able to add 1 power adder. My current plan is to add a turbo. It will be going into a fiero 5spd. most of the racing will be autox with some 1/8 mile heads up drag racing. the internals are pretty much open though. I have most of it figured out and am on a small budget but I have a few questions and am open to sugestions.
1. what piston wall clearance do you recommend?
2. are stainless steel valves worth the money?
3. I will be porting the heads and intake my self. any key areas to watch?
4. I will be twisting its tail pretty hard so is there any thing I need to do to the oiling system besides high volume/high pressure pump?
5. since it will be a turbo engine with very frequent oil changes. Every 3 to 4 events. how do you feel about synthetic oil vs regular oil and what weight do you recomind?

[sharkey]

1)- whatever the pistons require. i know you can get forged piston that require .009", some require as little as .003". follow what they recomend.
2) yes, deffinitly.
3)the walls arent that thick, so be carfull not to blow through. dont take out the air vane, it has to be there for proper mix of air/fuel. you can shape it, but done get rid of it.
4) realy just do the high volume oil pump
5) if you build your motor to gm clearances, just stay with 10w30. if you open the clearances up, go to 20w50. id run synthetic in it, it can free up a few hp. just mnake sure you break the motor in on dino oil

you have a good idea going with iron heads for a boosted aplication. however, there are some other options, and if you have not yet decided on a vehicle its going in, you may want to figure that out before selecting a motor. you could go with a 3400 engine in pretty well anywere you can put a 2.8 ironhead, as long as you are willing to do some work. a built up 3400 with a turbo will have great results, but it does require a lot of rewiring if you use a fiero. another idea is use the 3400 shortblock (for the extra displacment, and priority main oil feed) and cast iron heads. this has already been done in a fiero. here is the link http://www.fierosound.com/34engine/3400details.htm

[SappySE107]

You could use a 3.4 DOHC oil pump, as it flows 60% more oil than the stock 2.8/3.1 did.

[geoffinbc]

I dont know what year of 2.8L you are running but be sure it is 1988 an up because that is when all the upgrades were completed. If it MUST stay as a 2.8L but you can use aluminum heads then maybe you could bend the rules and run a 99+ 3100 engine with a 2.8L crank. This would be the best off all worlds.

[sharkey]

88 was when they went to the gen 2 motor. about half way through 85 was when they had all the upgrades complete (large mains, 1 peice rear main seal, ect).

mabey post some rules and what you have to work with. it would be best to select a car before you build the motor. if you stick with the fiero, you would have to do a lot of wiring to get anything but an ironhead running.

[614streets]

I have fageol kits if you want to slap on a blower kit. I should have them in stock 2 weeks after xmas. They are Brand new complete kits and can support carb or tbi, or if you want mpfi with one its an easy conversion with tig.

[geoffinbc]

88 was when they went to the gen 2 motor. about half way through 85 was when they had all the upgrades complete (large mains, 1 peice rear main seal, ect).

mabey post some rules and what you have to work with. it would be best to select a car before you build the motor. if you stick with the fiero, you would have to do a lot of wiring to get anything but an ironhead running.

Not in the fiero. They did not get aluminum heads ever. They did not goto internal balance until late 87. So that why I said get an 88 because that is when all the block upgrades were complete.

[keithcar72]

I should have told you in the first post that it is going into a fiero. the car will be mostly used for autox and some heads up 1/8 drags. it has to go in a street car but will not see any regular street duty. I need it to be a 2.8 for weight reasons. I can have one power adder but nitro is not allowed in scca. I have a limited budget, but I work at a junkyard and have access to a lot of equipment(valve machine,lathes,hones,crank polisher,etc). This is why I chose the turbo. the internals of the engine are pretty much open. for cost reasons I will be running stock rods but they will have the good bolts. I have a 2.8 with only 35k on it from an 86 fiero I had planed on using because it is in such good shape.

[SappySE107]

SCCA has a lot of rules, so you should check those out before you modify. A 3100 weighs less than the iron head 2.8 and makes more power plus more potential with the boost. That will be a very modified class though.

[Froggx]

Are you going to be autocrossing in a street mod class or something? I've autocrossed both turbo'd and NA cars before, and the NA are definitely better for autocross due to not having the weird lag of a turbo. A blower (non centrifugal) would basically have the same effect as an NA motor as you once again wouldn't be dealing with lag. Of course, you could run an undersized turbo and get rid of most all of the lag, and then choke it off on top end, which the iron heads seem to do anyway.

[keithcar72]

yes I am planing to run sm2. this means I will be running against miats, rx's, vetts and any other 2 seat production car. in my area right now the miats are the cars to beat. I had considered going na but i'm not sure if the 2.8 has enough ponys to keep up? I have also thought about using a turbo from a 2.2 chrysler it should be small enough to keep lag to a min. my biggest concern about the turbo was getting the cam and blower to get along with the computer. this is my first attempt at autox in ten years. I drag raced last year and ran roundy round for nine years befor that. I went to one last month and ran a toyota fx16 just to get a feel again, but did not see any fieros. I checked the points results for the last 3 years and nobody has ran any. I have already started on the short block but have not built the heads yet. This car is still in the air a little bit, but I need to make a decision soon since the first race in feb 8. and I plan to run for points.

[Anonymous]

If it were me, I'd use a 2.8L with a 3400 top end, and I would use a blower, becuz of its great low end, and in the 1/8mi it may even be far superior to a turbo, especially with the traction that the Fiero offers. Plus you have much less piping, and especially in a Fiero, it is a lot easier to intercool. Also piping is a bitch, and you will have minimal amounts with a blower. And it wouldn't be very hard to get a M90 or a Whipplecharger on top of a 2.8.

[Cannonball]

88 was when they went to the gen 2 motor. about half way through 85 was when they had all the upgrades complete (large mains, 1 peice rear main seal, ect).

mabey post some rules and what you have to work with. it would be best to select a car before you build the motor. if you stick with the fiero, you would have to do a lot of wiring to get anything but an ironhead running.

Not in the fiero. They did not get aluminum heads ever. They did not goto internal balance until late 87. So that why I said get an 88 because that is when all the block upgrades were complete.

88 was the ONLY year the Fiero had an internally balanced 2.8. All the other years (85-87) had an externally balanced 2.8.
88 was also the year when the superior suspension and brakes were offered.
The earlier year cars do have more available to them for aftermarket suspenions though since the 88 suspension was only one year. There are also tons of brake upgrades available for any year Fiero so these may not be enough reason for you to use an 88.
I would suggest picking what trans you use in the Fiero carefully though. Most of the 4cyl coupes came with a 5-speed Isuzu trans that has a pretty bad spacing between 1st and 2cnd gear that hurts performance if used behind a V6. The Getrag is the best choice overall but the V6 4-speed or the 4.10 4-speed (available only on 84 4cyl cars) can also be used with great success. The 4.10 might be your best bet for racing with it's ultra low gear in fact. It'd spool a turbo pretty quick i'd bet.

[Froggx]

lol, the turbo gets spooled with the 4.10's and you've left behind a massive cloud of smoke. Don't some of the fiero's with 4.9 swaps and getrags launch in 2nd on the strips because even 1st on that is too high?

It seems miatas are the cars to beat everywhere. Locally I autocross recreationally with a vette (my fiero has been torn apart for about 8 months now waiting for all the goodies to come together). Before that I autocrossed a turbo volvo. The vette is the easier car to work with because of the gobs of torque on demand and the fact that there is no waiting involved. In my opinion a supercharger is still optimal for an autox car. If it's any indication, there is a supercharged miata that runs around here, but no turbo miatas. In fact, one guy that runs here uses a 1st gen rx-7, and he says he prefers it over his 3rd gen because the NA motor in the 1st gen doesn't lag like the 3rd gen turbo even though the 3rd gen has a better suspension and braking setup.

[Anonymous]

If you have the time and money, which it sounds like you don't, you could even dive into a 2.8L DOHC project. Figure out a way to get the pushrod block to match the DOHC heads with oil passeges and such. There would be a ton of work involved, mostly custom, but IMO the gains would be worth it. Slap a M90 on top of that and you'll have power from idle to the 7,000rpm(or higher...) redline.