• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Some Questions about doing a mild build L67

88formula

88formula

New member
I have a 1988 Pontiac Fiero Formula, with a mostly stock L67 drivetrain from a 98 GTP. I will be dropping the cradle this winter to tear into the motor and do a gasket overhaul. While I have good access to the motor I am considering doing some modding. I currently have a FWI, Magnaflow catted 3" downpipe with 2.5" exhaust, colder plugs, 180 t stat, EGR and EVAP delete... in 2013 my car will be emissions exempt and I will probably be ditching the CAT and redoing the exhaust... I plan on getting a tune, not sure yet if I want to order a box tune, buy a tuner (no experience), or take it to a local shop to have it dyno tuned. I also want to run a VS cam from ZZP since they say it can be used with no other modifications, but I am not sure about this being true? Also I am considering headers, but am unsure if I will be able to use Speed Daddy's or some other cheaper ones without modifying them, but I also am unsure of how much running the stock manifolds is holding me back. I planned on going to a 3.4 pulley too. How does all this sound? Any input/suggestions/insight would be greatly appreciated!
 


The VS stands for valvetrain safe. Many people find that the springs break when they put this cam in w/o changing them. I highly recommend changing the springs and retainers, and it's easy when you have the motor out. As long as you do that, XP/S1X are both easily doable. Both would give you a little more than the VS on the exact same mods.

The front exhaust manifold is holding you back. It necks up pretty nasty. That can be fixed with a power log or other free'd up front manifold.
 
BillBoost37, thanks for your input. Wouldn't the XP cam require more upgrading/modding to the valve train? Like a stronger timing chain setup, modified retainers, and stiffer then stock springs? Also in your opinion are you saying that if I got a powerlog my exhaust wouldn't be restricting me anymore? Modifying headers isn't too big of a deal because I am a custom metal fabricator by trade. So one upgraded manifold = 150$ or cheap headers self modified (250$ish). Also I know to find out for sure I would have to scan, but how do you think I would be doing with KR with that setup running a 3.4 pulley? Thanks again
 
Xp requires stronger valve springs, upgraded timing chain or you could run a new stock timing chain but check its condition every couple thousand miles for any stretch etc. power log would be better then out stock manifolds how headers would flow better :).
 
Take another look at what I said.. I don't feel that you can put on rockers or the VS cam w/o upgrading springs. Too many people have broken springs following what ZZP said about it being perfectly fine. So, in my world you are upgrading springs and retainers anyway. As long as you do that, put on a new stock chain (which you likely would anyway with VS cam install) and put in the better cam.

On the exhaust. If you fabricate, hell..make your own Plog etc. and you should be reasonably without KR on that setup. Tune it and you'll have a pile of power and no KR.
 
Also being a fiero, you weigh less than a normal wbody 3800 car.. So knock due to stress from weight on the engine is less. I am sure you could get away with a log and the downpipe is easy as hell on a fiero..
 


Fiero can basically get away with manifolds and an open downpipe...lol.

It'll flow alright.

I'd venture to say Crow 105's, a VS Cam, whatever exhaust you want to run, a 3.4" pulley, and an intake/tune...you should be well into the 12's...if not cracking on the 11's.
 
Blueguy91, do you speak out of experience or theory when saying a fiero with stock manifolds will not have worth while improvements going to headers?

Assuming I wouldnt be stressing a new stock timing chain too much I think I may go with the XP cam and 105s. I would like to keep a daily driver reliable setup, but comparing the numbers of the VS and XP it does not look like too big of a difference. Plus I have to admit the XP produced a much nicer lobe to the exhaust! I have also decided after reading around the how-to's forum that I will be porting my LIM and Supercharger, and blocking off the silencer ports (just because)

Also anyone see anything I should add to my list of stuff to buy for tearing the motor down and modding it?
valve cover gaskets
supercharger gasket
intake manifold gasket
throttle body gasket
front cover gasket
oil pan gasket
transmission pan gasket
transmission filter, with new fluid
timing chain w/dampener
105# valve springs w/new retainers
intake and exhaust valve seals
2 jugs of coolant
spark plug port adapter
valve spring compressor
crankshaft pulley dampener
assembly lube
ZZP MPS w/3.4
rent ZZP pulley puller tool...?
SSAC headers? $225 shipped figure you cant beat that!
Flowmaster 80 series
thinking I want some nice 3.5inch chrome tips. singles. slanted.

ANYTHING (parts, special tools, Lubes, sealants, etc etc) anybody can point out for me to add to my list would be greatly appreciated!
 
Usually don't like the sound of flow master with our engine but being that its a Fiero it may sound different
 
Right now I have a 3 inch high flow cat and a single 2.5", 12" long glasspack... It doesn't sound too terrible, and I'm sure a cam will help things out. From what I have read it is near impossible to make a L67 sound good :( another idea I was throwing around is going to dual 3" glasspacks. But who knows.
 
As of now I have ported my TB, removed a majority of the MAF bridge, ported the LIM some and hogged out some on the coolant loop, ported my blower case and made a silencer port block of plate. 180* tstat, autolite 104's, EGR and EVAP delete, also have FWI... I plan on ordering SD headers off ebay as soon as I see them back on there (checking everyday!) since I keep hearing bad news about SSAC holding your money etc etc. I will not be running a cat in the exhaust, so being my car is a Fiero basically it will be open headers.
I had originally planned on using a 3.4 pulley and VS cam, but now I am leaning more towards a 3.25 pulley and XP cam, From what I have read I think I can pull it off with the lighter platform ( car weighs around 2600lbs).
 
Last edited:


Listen to some 3800 Fieros on youtube, then listen to some GPs with the same muffler pipe diameter etc. They sound much different! Not going to argue anything about firing order or that either of them sound "good", but due to a much shorter exhaust there is a clear difference.
 
SlowNA06 said:
Oh, so the firing order changes if I put my engine in a different car? Good news everybody. :th_burger:
Click to expand...

They don't sound the same go find a clip of a Fiero and a go with similar exhaust quite a bit of difference. There's a local that has a L67 stuffed into his Fiero running Borla just like mine and there's a noticeable difference.

Of course it's a 3800 so it's hard to get it to sound good
 
Ok I have been doing a ton of reading lately about E85. I am seriously considering going to 60# injectors and 3.0 pulley now. I live in the Atlanta area and there is E85 available all over the place around here, and from reading in the Southeast regional forum I have found out that a local does great dyno tunes with these cars, and is only about 15 minutes from me!
 
Last edited:
E85 is a must to make make power out of forced induction id do it in a heart beat if the GP wasnt my DD, also L36/L67 sound good in the f bodies much better then the w bodies
 


Finally buying some parts for the build. motor has been tore down to the block for a couple weeks now, so far got polished aluminum valve covers for 50% off and MPS with a 3.25 pulley at 40% off... watching their facebook page anxiously waiting on the cams to go on sale!
 
88formula said:
Finally buying some parts for the build. motor has been tore down to the block for a couple weeks now, so far got polished aluminum valve covers for 50% off and MPS with a 3.25 pulley at 40% off... watching their facebook page anxiously waiting on the cams to go on sale!
Click to expand...
Bastard I was trying to get those same valve covers @ 50% and was having problems with the site. LOL

Cant wait to see your progress going to be a nice little setup. Can we get some updated pics please.
 
Txslow6, I will try and find the time to start a build thread on here some time. I have taken pictures and put them on Facebook since the beginning, so I have a couple hundred. I expect to have the car put back together early this spring :)
 
You must log in or register to reply here.
Back
Top