turbo charged 3.4 dohc....430 rwhp!

[pontiacjeff]

If you aren't wanting any more power, you are wasting your money on a forged bottom end. Get the ARP rod bolts in and HD bearings. Don't bother with the springs or lifters if you aren't looking to squeeze more RPM or boost either. Just rod bolts, and bearings.

He's gonna end up with more power...

[SappySE107]

If you aren't wanting any more power, you are wasting your money on a forged bottom end. Get the ARP rod bolts in and HD bearings. Don't bother with the springs or lifters if you aren't looking to squeeze more RPM or boost either. Just rod bolts, and bearings.

[FerrariFan]

First of all, thanks for the quick and informative responses! This is really going to help. Sappy, thanks for the PM. I'll try to get those measurements for the ARP head studs to you. No, unfortunately I wasn't using ARP bolts on the bottom end and was actually surprised I didn't have this problem sooner.
My goal isn't any more horsepower than I can get from 15 psi since I still plan on using $8f with the 2 bar map and ECM I'm using now. As it was, I could break the rear end loose very easily in second gear. Any more power would just tear up my tires or grenade my 282 tranny. 15 PSI will probably require a bit more fine tuning from Jeff. What is the advantage of the lighter lifters and springs? I don't plan on revving the engine any higher. If anything I think I'll reduce the rev-limiter a couple hundred RPM to be safe. Jeff also suggested incorporating a programmable MSD ignition for a soft rev-limiter instead of the ECM fuel cutoff which is pretty harsh. BTW, what is the difference between the 3.4 DOHC pistons and the 3400 if one will fit in the other? Do you have the 270 HD degree bearings that Joseph mentioned?

Joseph, even though I hadn't run into any detonation problems think just a bit lower compression would help the reliability, especially if I'm going to use a new block and pistons with tighter clearances than the high mileage engine I'm using now. Tell me more about crank. Where did it come from? Why aren't you going to use it?
Lance

[pontiacjeff]

I'm building the engine for Lance. I was thinking of putting the valve reliefs in a set of forged 3400 pistons, Sappy, what do you think about that? Or with that big ol dish, will valve notches even be necessary? I'd like abt 9.0:1 for this, don't know the cc of the dish on the 3400 pistons, do you?

Sorry to hear about that, not sure what main bearings you have but there are 3 types now, ~135 degree upper groove, 180 deg groove, and the latest 270 deg grooved main bearing. The greater the groove the better the rod bearing lubrication at a little expense in less problematic areas of crankshaft lubrication. Connecting rod failure in early model 60 degree motors isn't a surprise considering the number of Fiero 2.8s that did it.

I still have a stroked and radiused forged crank 3.43" if you're interested. I used clevite HN bearings in my last rebuild and loosened my bearing clearance to ideal .0024" and use 10W40 for the increased loads. Unless you plan on running a lot more boost I wouldn't lower compression unless you've found it to be problematic already.

I'm at 4psi until I open the exhaust up and ~11.0:1 compression on 93 octane, I'm spraying water but I don't need it at the moment. The bearings in the last motor took a hit because I gave 5W20 a try with tight bearing clearances .0018" that caused intermittent oil light tripping at idle. I didn't consider the extreme compression at the time ~11.6:1 with the tight clearance at the time of that experiment which probably would have been fine with stock compression and clearances.

[SappySE107]

Did you have ARP rod bolts in before or just a bone stock bottom end? What hp goals do you have now? 3500 crank will need to be turned down on the rod journals, and you will need to deal with the 7x sensor. I personally wouldn't bother with that in a 3.4 DOHC (and I have a 3.4 DOHC). i would add a crank scraper to the list though, since its cheap and well worth the money for something that can spin to 7k+. I have rods and HD bearings in stock, but I do not have pistons for the 3.4 DOHC. I can do 3400 based pistons with a small dish to give you whatever compression ratio you want however.

Other options are the lighter lifters and stiffer comp springs, which i am running in my motor. I replaced the belt just to be sure when I did the cam timing, and the stiffer springs aren't effecting the belt at all.

I already PMed you back about the head studs. I can get measurements on the studs that I think fit but I don't have a carrier here to double check any more. Could have sworn I checked all that before but its been years.

[FerrariFan]

Hi guys,
Thought I'd update you with the latest news. The inevitable has happened and after two years my boosted stock '97 LQ1 finally spun a rod bearing. I had the boost dialed up to 15 psi and may have over-revved it. Bottom line is that I found the limit of what the stock bottom end can handle. Two years ago it dynoed 430 at 12 psi so who knows how much more it was pushing at 15. Now my goal is to pull the engine and build a bullet proof bottom end that can handle 15 psi with no issues. I have a new 95 crate engine that I can use for parts, maybe just the block and crank. (or sell it to pay for parts)
I've been researching forged pistons but haven't found any part numbers or a good source. I know others have ordered custom forged pistons for a boosted engine and I'd like to piggy-back on that so I don't have to start from scratch with dimensions and compression ratios, etc. As far as the crank and rods go does anyone know for sure what the best route to go is? I've read about using the 3500 crank but is is necessary and how much machine work is involved for it to fit?

So far I'm looking at the following:
Forged aluminum pistons with slightly lower compression.
SBC forged performance rods
performance bearings
ARP fasteners for the bottom end and heads
maybe 3500 crank?
What else am I missing?

Thanks,
Lance

What code is your VVT engine running? Is it turbocharged?

8F, yes it's turbocharged

[FerrariFan]

What code is your VVT engine running? Is it turbocharged?

If had known about code 59 a couple of years ago maybe I would have gone that route. I read that it's good for up to 30 psi which is way more than I will ever run. $8f is good up to 15 psi, it is tricky to tune though since there are so many tables, flags and constants to deal with, a lot of them not very well documented. Is anyone here running a turbo 3.4 dohc on $59?

If you had started with a 730 ecm code 59 would only be a single wire relocation and tuning away. Not sure if it would turn out to be the same with the 727. The difference is a ground for one of the injector banks. I purchased a fancy timing light to help me when I return home, in the effort to switch from 8F to it as there were problems for all who tried to use it with DIS ignition and the few that succeeded with it on DIS in my oppinion have provided little to no appreciable guidance on how they did it. I know of no 60 degree motors running on it at this time.

Whatever the case the problem is setting the proper timing limits in the code so the timing logic does not fault on start up attempts. I believe part of the problem is that the total timing commanded is outside the programmed limits as it relates to the distributor settings due to the considerably reduced timing with the fast burn aluminum heads in some areas of the spark table. Everyone that I'm aware of who tried it with an aluminum head 60 degree V motor had the same results including me. I did succeed at getting the engine to run although poorly for a brief period on my first attempt.

That's what the timing light is for, to help me identify what's going on with the timing as values are being changed in an effort to sort it out. Since I along with at least one other person who attempted it were dealing with the 3900 which has no timing marks for reference and has since been discovered that the VVT camshaft is extreme at full advance and full retard suggesting this may have contributed to the problem as the cam in both engines was fully retarded at the time, and apparently the only reason my engine started was because the camshaft was reground to specs that made it more efficient than the stock specs did fully retarded. The other members engine with the stock cam retarded would not start at all and that explains why despite my success my engine took several attempts and starting fluid for an initial crank and run.

Code59 is very nice and has some impressive add on features.

[FerrariFan]

If had known about code 59 a couple of years ago maybe I would have gone that route. I read that it's good for up to 30 psi which is way more than I will ever run. $8f is good up to 15 psi, it is tricky to tune though since there are so many tables, flags and constants to deal with, a lot of them not very well documented. Is anyone here running a turbo 3.4 dohc on $59?

[robertisaar]

$8F is TGP.
$59 is extra-awesome though.

[RedZMonte]

8F is TGP code? Im running OBDII on my Turbo LQ1. I use DHP Powertuner to do my tunes (no chip to swap or burn).... MAF based (1 bar map). I think its easier to use on the fly BUT OBDI i think you can do more with.

Again great job, LOVE it.
S

[FerrariFan]

Cool it runs on 8F ! thats awsome, I thought I was the only one left using 2BAR 8F stuff. nice build !

Only one left? You can tell how long ago I started building this thing . What are most of the other turbo's running? $59, Haltech?

[Mars]

Cool it runs on 8F ! thats awsome, I thought I was the only one left using 2BAR 8F stuff. nice build !