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Discussion Starter #1
Currently running a stock '91 EFI 302 with 122K miles. To keep build time and costs under control, I didn't do anything to the donor engine during the initial build other than pumps, chain, distributor and wires. I also wanted to get a feel for the power so I'd know how much to build. For a winter project, I'm planning to do a complete rebuild, to freshen everything and get a modest power increase. I want to maintain as much drivability as I can and keep the project on a pretty tight budget. Secondary goal: learn how to do some new things.

So, I'm reading up on DIY porting and polishing the stock heads and intake manifold, using the Standard Abrasives kit. Also planning on better shorty headers and probably an E303 cam. I figure that I may get about 30-40 HP from those mods - that would be plenty for me.

Here's my question: If I make those mods - all of which should make the engine breathe better - would I also need to step up to a bigger mass air flow sensor or bigger injectors? How about without the E303 cam?

Thanks.
- Steve
 

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FFCobra Captain
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I've always read here that heads are the most restrictive part of the engine, so if you want to keep it on a budget, then do just the things you mention.

You can always save up and add a bigger TB & MAF later one..those are simple bolt on items and could be put on at any time.
 

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Porting the heads/intake and adding a good set of shorties will probably not require that you step up in injector size. I believe the 19lb stock injectors are good up to around 300 hp and you shouldn't be near enough to that to be concerned. I went aftermarket heads, intake, FMS headers and E303 cam and ended up with 281rwhp. Jumped up to 24lb injectors and the a/f ratio seems to be right on.
 

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FFCobra Master Craftsman
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As far as I know the most restricting component on a stock setup is the lower intake.
It chokes the whole induction system.
So first thing would be to get another intake, perhaps a cobra, or aftermarket one.
Than match the head ports to the lower intake.

Good luck.

Olivier
 

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Ported stock heads, aftermarket intake, and E303 will be fine with stock injectors. You would likely realize the most gains from a larger mass air meter. I'd keep the stock TB and save your money there. Put that money toward a larger fuel pump - at least a 155lph. You'll also want better springs in the heads with the E303 and roller rockers would be a wise idea as well. Personaly I would keep the stock cam and put 1.7 rockers on it ( still upgrade your springs though ). Find a used set and install them anytime afterwards.

You want the best possible tutorial on porting stock heads?
Get this DVD and follow it:
http://hometown.aol.com/valakoraceheads/page11.html
 

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One more thing - the GT40, Cobra, and Explorer lower intake ports are pretty close match to stock size intake ports on the stock heads. You shouldn't have to gasket match excessively if you port them.
 

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I know that you indicated that you were on a budget, but I would suggest that purchase a set of heads or having them professionally ported. It's a very time consuming process and for around $500 + core, there are some nice options such as the amuninum "take-off" GT40, Thumper, Power heads, etc. Do a web search for "ported e7 heads". There are some nice options out there to get that next step up in porformance.

BTW, I have the Thumpers, 1.6 roller rockers, gt40 springs, E-cam, (TMOSS) ported upper and lower Explorer GT40, 65mm TB/EGR, Pro-M 75mm for #24 injectors. Though I've only go-carted, I'm extremely pleased with the combo. Also, underdrive pulleys help the performance somewhat.

Here are some links:
www.powerheads.com
www.hunterstyle.com/thumper/combos.php
http://www.tmossporting.com/TechArticles/WhyPortaLowerIntake/tabid/328/Default.aspx
http://www.fordmuscle.com/phpBB/viewforum.php?forum=11&297
http://www.armstrong.edu/ron/auto/e7.html

HTH,

Marc
 

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Steve,

I need to steal your thread for just a couple of questions to Wurf…

Wurf,

I’m no FI expert so here are a couple of questions about your post. You suggest a larger MAF with stock injectors and a larger FP. Where would the gains be…? It takes a given amount of air and a given mount of fuel to produce a given amount of HP. The EEC-IV will still maintain the stock settings of 14.7:1 for AF. Is it because you would be flowing more air and therefore more fuel at the given AF ratio..? It the stock FP to wimpy to support any more flow that with a totally stock setup..? I know that a 155 LPH will support ~ 490 HP. What is the stock unit capable of..?

Thanks

Chris
 

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Steve,

I know that you indicated that you were on a budget, but I would suggest that purchase a set of heads or having them professionally ported. It's a very time consuming process and for around $500 + core, there are some nice options such as the amuninum "take-off" GT40, Thumper, Power heads, etc. Do a web search for "ported e7 heads". There are some nice options out there to get that next step up in porformance.

BTW, I have the Thumpers, 1.6 roller rockers, gt40 springs, E-cam, (TMOSS) ported upper and lower Explorer GT40, 65mm TB/EGR, Pro-M 75mm for #24 injectors. Though I've only go-carted, I'm extremely pleased with the combo. Also, underdrive pulleys help the performance somewhat.

Here are some links:
www.powerheads.com
www.hunterstyle.com/thumper/combos.php
http://www.tmossporting.com/TechArticles/WhyPortaLowerIntake/tabid/328/Default.aspx
http://www.fordmuscle.com/phpBB/viewforum.php?forum=11&297
http://www.armstrong.edu/ron/auto/e7.html

HTH,

Marc
 

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Chris,
The stock MAF meter is relatively small, something like 58mm IIRC. It's actually smaller than the stock TB, plus it has the element and sample tube sticking into the air stream causing turbulence and hurting flow. Fairly common to upgrade to a 75mm unit or similar even with mild mods, but the gains are greater when the rest of the motor is breathing better and it becomes more of a restriction. On a totally stock motor it wouldn't make any difference.

In all honesty, the gains would actually be fairly minor with the meter swap, but it would make his work porting the heads and money invested in a better intake manifold more easily realized. It also sets him up for future performance upgrades ( to a point )

As for the stock fuel pump, it can barely support the stock engine regardless of any calculations you could make for it's 88lph rating. The fuel pump is an insurance part.

The 19lb injectors should be just fine with ported stock, Thumper, Tmoss, Power heads - whatever you like. Even GT40, GT40P or Edelbrock Performers would work as long as the stock injectors are clean and flowing evenly.
 

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Wurf,

Thanks, appreciate the reply… I just spent $20.00 on a book so that I could understand the FI world. I can't wait to read it...

Steve… back to you.. :D

Chris
 

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Discussion Starter #12
Wurf -

Re: your cam recommendation... what's the performance trade off between an E303 with stock rockers vs. the stock cam with 1.7 rockers?

- Steve
 

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Steve,
What heads and intake are you running?
Speaking in generalities here.

This would vary and depends on the heads and everything else, but I would guess 10 to 15 peak hp would be most you might see. Less than that with stock heads unported etc. The better the heads flow at the lift added by the E303, the better it works.

A stock cam with 1.7 rockers give you apx .472 lift. The E303 with a 1.6 is .498 lift. Stock unported E7TE heads are typically done flowing any more air above .440 lift.

The 1.7 rockers open the valves quicker and add some flow that way. There's also a reduction in friction from the roller trunion, but you would run 1.6 rollers on the E303 too so.... We're not talking a lot of HP here - maybe a handful.

That would mean most of your additional HP is due to increased duration which typically raises the RPM power point at the same time.

I'm not a big fan of the Ford Racing alphabet cams in general even though I am running a Ford Racing cam and ran an E303 in the past. My current cam is a flat tappet grind and not an alphabet hyd roller. It's also dual pattern - a feature none of the alphabet cams have.

If you really want to notice a difference in performance you need to first add airflow to the motor with better heads and intake and then match a cam to your setup. Comp makes really good stuff if you want to go off the shelf. They have much more aggressive lobe profiles and dual pattern grinds that work better with Ford heads for the most part. You'll get "more area under the curve" IE quicker valve actuation for a given duration period allowing more air to flow past the valves into the motor.

Fact is on a mild or stock 302, the stock cam is not THAT bad...actually pretty good. On the other hand $160 for an E303 or a TF stage 1 gives you rumpity sound and a little more power so why not.

For another $80 you can have a custom ground cam that should add more power everywhere.

I'll post an Excel spreadsheet you guys might find interesting. It's from Buddy Rawls, a well known custom cam guy for SBF motors.
 

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If you could recommend a set of aftermarket aluminum heads, complete and reasonable prices (like the Edelbrocks), which would you choose?
 

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A set of AFR 165 heads will really wake up an engine.
 

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Heads and cam...remember, your engine is a big air compressor!

Also, for your shorty headers I HIGHLY recommend BBK's equal length ceramic coated headers. Check Summit's website.
 

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Where is 331Notch today?
Man...I know he'll put something up here once he sees this stuff.

Chepsk8
AFR165 are great heads.

Personaly I'd put Trick Flow twisted Wedge on my stock 302 and run a Weiand Stealth carb intake with a 600dp carb.
 

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Discussion Starter #19
Eat's m...

I know that equal length headers are generally better. For shorties, is there a meaningful performance gain over non-equal length?

- Steve
 

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Steve,

If you're going to remove the engine and rebuild it, you might consider a stroker kit. While the engine's out, put in a cam also.

If your budget doesn't allow the other mods at this time (heads, MAF, etc.) you can do them later without removing the engine.

Charlie
 
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