All,

I have been off the list for a few years, so apologies in advance for my lack of participation.

I'm ready to resume some mods on the truck, but I've got some questions that I just can't find warm and fuzzy answers for. I've been searching through the archives, but haven't run across anyone with my set-up.

94 F150 Supercab Flareside, 5.8, e4od, 3.73 gears, Cervini Ram Air Hood,
Vortech S-trim 6 lb.

Engine has 175K miles. runs good, but it has an exhaust leak at the manifold / head and a small oil leak at the rear main. one manifold stud is already broken and I expect to break a few more trying to get the exhaust manifold off.

So, I thought, Pull the engine and while it's out do the following:
- port / freshen the heads
- fix the broken exhaust manifold stud(s)
- add headers
- new high flow exhaust and no cat
- replace the rear main seal and oil pan gasket
- and maybe add a speed density cam

And now the questions -
- exhaust, I'm nervous about loosing low end torque. any recommendations for headers? I'd like a single exhaust exiting in front of the rear wheel, with no drone and loudness comparable to maybe a stock mustang cobra (I like the stealth approach).

- Cam? I read an article by a James Oxley on the off-road forum who said a list member was running a lightning cam with a speed density set-up with great results. I'd really like to find out who this guy is and pick his brain.
I've also tried to reach James Oxley with no success.

I know I could go to mass Air, but frankly the additional budget isn't there, and I keep reading it can be done with Speed Density). I've also read about not going below 114 deg on the lobe separation on the cam.

So there it is...my dilema. what exhaust for a blower engine and what cam for a speed density computer. BTW, the compression is 165 to 175 on all cyl.

Hope someone out there can help.

Thanks.

Kind Regards,

Delray Dobbins
Columbus, OH

 

Getting those studs out is going to be a bugger. Invest in some reverse drills and taps, and be VERY patient. If you have a torch and a welder, tack weld a lever onto the broken off heads and try to ease them out after applying a bit of heat. Otherwise, drill and tap...

I'm not much use for the rest of the stuff though...

 

yep. they are quite well rusted. had planned as you suggested, reverse drills and taps, and plan for several days of s-l-o-w progress. this was the trigger to pull the engine. no way to squarely drill the studs out with the engine installed.

thanks,

Delray Dobbins

 

Sounds like you got good info so far. The Crane cam I have was a common upgrade from the Lightning cam... which is only slightly different from the stock cam in your motor. Better heads will really help you, the stock heads got no busiiness on a NA 5.8, never mind ones that's force fed. I'm guessing you have an FMU with the blower, better flowing heads and a cam will put you way beyond what the stock injectors should be used for, how do you plan to address that?

 

Aside from the plans you have, tuning will be essential with speed density and boost. The speed density ECU's cannot read/register anything above 99.6 engine load.

 

Corect, using a FMU with a t-rex boost-a-pump. hmmmm...if a cam is going to force me into bigger injectors, would that also force into mass air?
(more than was budgeted for this go around). total budget this time is 1K to 1500. headers (still need some recommednatiojns) , exhaust, and maybe port the existing heads? are the existing heads even worth porting?

I have to admit, I've had to do NO tuning so far. There is a Dyno somewhere around here, but I'm a bit intimidated by tuning. I assume tuning equals chip burning. Who should I talk to about custom chips for a speed desnity?

Is it realistic to just open up the exhaust and port the heads to maximize my current set-up without getting into new heads, new cam (and valvetrain), that alone sounds like another grand.

I'd probably feel more comfortable going larger injectors and tuning once I talk to a chip source that convinces me they know what their doing.

99.6 engine load? that's a new term I haven't ran across before how is that sensed / calculated?

it's tough to keep the work scope in check.

 

As far as headers look @ Mac Performance - performance accessories for cars, trucks, and motorcycles

Great headers @ a great price

 

It forces you into a system you can tune, not necessarily a mass air system, but those are the ones that are fully compatable with the popular EEC4 tuners.

Are you still running the stock exhaust? Maybe just do the exhaust now and leave it at that.

You won't find very many, it's mainly the mass air systems of this era that were reverse engineered to develop tuner systems.

It's not worth sinking any money in the stock heads.. at all.. IMO. Even fully ported by an expert with a flow bench they're restrictive on a 5.8.

Once you get cam, heads and exhaust on this motor you're going to be way beyond what the stock computer was designed for.. into the 60lb/hr range for injectors. I'm currently looking at heads for my NA 5.8 and it will need 30lbs squirters for some of them. Honestly, from the things I read online the only guys that are happy with thier blown motors are the guys that figure out how to tune themselves... drag racers being he exception. Many of the dyno tune shops are hacks at best, they just do enough to get a motor functioning as quickly as possible and show the owner a big number. If you want to iron out all the subtle little issues(rich idle, lean midrange, emissions) you'll spend thousands on repeat visits to the dyno. It quickly becomes much more cost effective to get a tuner like Tweecer or EEC Analyzer, a wideband O2 sensor, and DIY it.

 

All,

thanks for the comprehensive input. I checked with a local exhaust place and a machine shop today. Here's the short of it.

Machine shop wants 150 a head to freshen up. 300 ea to port. Have determined porting is not worth 600. to spend that much might as well get an aftermarket set of heads. next time. stick with the freshen up, if necessary.

found BBK's quoted at local Jegs for 255. they did not carry Mac, though I'll still look up a price on that.

here's the sticker shock....exhaust shop wants 600 bucks to do the system from the headers back, Y pipe, single exhaust, one cat, one muffler, side exit behind rear tire.
seems kinda high to me. Given the blower, I asked what size pipe after the Y, he said 2 1/4 would be fine. sounds awfully small...i expected 2.5 to 3". I think I'm off to find another quote locally.

looked up under the truck and the rear main is leaking pretty good. Found a GREAT link in the archives to the bronco site where a guy posted the pics of his rear main repalcement. Kudos to whoever takes the time to archive the endless posts.

PLanning on pulling the engine this weekend. STILL cannot figure our where the exhaust leak is coming from. my Dad swears it's the small freeze plugs in the heads that have rusted out like his 460 did around 1980. Do these heads even have the small dime size freeze plugs?

So, pending a compression test tomorrow or Fri, pull the engine, fix the rear main, pull the heads and have the machine shop fix the manifold bolts at 15 ea, put it back together with fresh headers and keep making boost.

I'll be curious to see what the compression numbers are for a 175K engine running a blower.

will keep you posted.

Kind Regards,

Delray Dobbins
94 F150 Supercab Flareside, 5.8, Vortech S-trim, 3.73, lowered 2/4, Cervini Ram Air hood, best ET 14.90

 

Exactly, these heads here flow 50% better than the stock heads for about $1k a pair.. Dart: SBF Iron Eagle Heads



Idiots, you want at least what I have... 2.5" mendrell bent Y section into a 3" cat back with a 3.5" tailpipe. The system I have now I made myself to replace a muffler shop job, and I felt the difference it made right away.

 

You can get by with an FMU, B-A-P and timing retard, but that is not the ideal way to feed a supercharged application. Larger injectors and a good fuel system, with aftermarket tuning, is an easier/safer way to dial in your combo. If your fuel system can support the power the engine makes, without an FMU, then that's even better. Don't worry about running 60lb injectors unless you're flirting with 500rwhp; you'd be surprised how far a set of 30's will go on a boosted application.

Something to think about with injector changes, for boosted applications, the fuel system needs to be able to feed them. You don't want the fuel pressure to fall off at higher RPM's...this is an indication that there is not enough volume and upgrading the injectors will not fix this issue; you need to watch your fuel pressure (at WOT), especially with speed density.

VE (volumetric efficiency) or engine load is a percentage as to how much air is flowing into the engine. 99.6% load is near the engines max capacity; for a 5.8L that's about 5.77L of air going into the engine. A boosted application will produce numbers above 100% because the compressor can force more than 5.8L of air into the engine; this is important to know when tuning for fuel and timing.

 

Matt,

thanks for the info. Agree, the Sd system is not the ideal system, which to your point is why i put in fuel press and boost gages on day one. they have been invaluable in diagnosing a faulty hobbs switch and bad in tank fuel pumps, which triggered the t-rex purchase. Very interesting thing...when the blower was on between 20K to 50K miles, the in-tank pumps fully kept up...up to 7 lbs of boost. when I put the blower back on at 150K miles, the orig pump couldn't keep up and neither could the replacements from Auto zone....so enter the t-rex. It cannot be stressed enough....in real estate it's location location location, with blowers it's fuel fuel fuel.

did the compression check today....all 170-175 except # 5 which is at 165 psi. All the plugs looked perfect. Start pulling the engine tomorrow. Final workscope, fix the broken exhaust bolts in the head, fix the rear main, new oil pan gasket, and new headers / exhaust system.

A few of my friends think I'm nuts for not going completely through the engine, but it seems to be doing well on the compression and only using 1 qt of oil every 4K miles. so I'm gonna leave the internals alone.

Off to one more exahust shop tomorrow for another quote. Started looking at Bassani Y pipe and catback as an alternative.

One thing, Must I break open the AC system to remove the engine? I'm seeing conflicting info on this. I'm hoping to the lay the AC compressor up on the cowl under the winshield and not evac the system.

PAUL, thanks for the specs on your exhaust. that sounds the way to go. nothing smaller.

Regards,

Delray Dobbins

 

I managed the engine swap in my truck without disconnecting the the AC. I did have it evacuated though.. just in case. I did my engine swap right at the time R12 was being phased out so if I lost the refridgerant I'd have to convert to the new system.. which would have cost plenty.

 

If you plan on doing other mods beyond what you plan now, then go with a 3" exhaust.

There is a dual tank trigger you can use to help support more fuel. I used it with my speed density combo and the mass air combo I have now. In general, it triggers the rear tank pump (when running off of the front tank) to send more fuel to the rails under boost.
I have a Walbro 255lbh, boost activated inline pump, a dual tank trigger (at about 6psi) and 42lb injectors. And I also do my own tuning and datalogging. At WOT, under full boost, both tank pump with run, as well as the Walbro inline.
Otherwise, the fuel system operates like stock, under normal driving conditions.

 

Mac Performance - performance accessories for cars, trucks, and motorcycles
You can buy Mac Headers from Mac for less than BBK @ jegs. They even have ceramic for a good price & they are equal length. Click on Mac not performance.