86VETTEMAN

I port upper plenum , install siamese runners, and port the base. Can it handle a 383 stroker, ZZ-X cam, and AFR190's. Or will it still hinder the performance. The reason I am asking is, I can't see spending $1250 on the Mini Ram and $1300 on the Superram. The Holley Stealth Ram is my best bet but, I cann't run the stock distributer and I would have to modify it for the EGR. The EGR wouldn't even be certified. So, the only logical thing would be modify the stock set up. Any info./opinions? I have a setup in mind that would create 405 with Vortec Base and stock(port/Poslih) runers+plenum. About 525 with Mini Ram.

MrNuke

I was thinking the SAME way you were.. But after I had my superram installed.. WHOA!!! HUGE DIfference. it IS worth the $1000+ for it.. The added Torque and HP can't be beat.. :cheers: :thumbs:

...ps they are emissions legal and are the only ones that retain the EGR functionality... which I NEED here in CT..


[Modified by MrNuke, 6:48 PM 4/17/2003]

vader86

Hard to put a figure on the power limit, I would say that you should be in the low 12s at best.


[Modified by vader86, 8:15 PM 4/17/2003]

65Z01

Before you try the super-ram; give the siamese base a try.

It will certainly raise your RPM limit with better breathing.

86VETTEMAN

Thanks for the replies. I will try the siamese runner/portede plenum and base first. I can always sell them and get the Super Ram later. The bottom line is they will help a great deal but still might be a weak link in the upper HP range, Yes?

grumpyvette

I tried about a dozen differant combos of moded TPI intakes before going to the custom steath ram. the BEST I found before swapping was a ported ACCELL BASE with SLP siamese runners siamese ported 3" into the upper runners, leaving the lower runner and base ported larger but NOT siamesed to retain the ram tuning effect and the plenum fully ported, similar to this picture YOU MUST PORT THE PLENUM ENTRANCES TO MATCH OF COURSE


THIS PROVED TO KILL LOW END TQ WITHOUT A BIG OR REALLY ANY GAIN IN HP UP HIGH
[/b]




[Modified by grumpyvette, 5:35 PM 4/18/2003]

devilfish

I seen dyno numbers on siamesd ported base that prove gain in the upper RPM range? I bet 65Z01 can fill in here better...

grumpyvette

look, heres the dynos for a siamese intake
http://www.eecis.udel.edu/~davis/z28...age010511.html




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having done similar mods and having dynoed the results (HERES A SIMILAR DYNO RUN) I can tell you that the results will be a loss in low rpm torque, below 5000rpm where your engine spends 90% of its time and a loss in volumetric cylinder filling efficiency below 5000rpm and a slight gain in hp over about 5000rpm due to the shorter runner length lower restriction to the air flow, (stock the TPI flows about 190cfm)
http://www.eecis.udel.edu/~davis/z28...age010511.html

notice the loss of torque and the gain of only 10 hp! look 1/2 way down the page at the chart

now what would help would be porting just the upper 3 inches of the siamesed SLP runners and the PLENUM and useing an EDLEBROCK base with its bigger port size and straiter runners.

look the stock TPI has runners 15" long with about 3 more inches of runner in the cylinder heads , for a total of 18" of runner length, with that length runner both the 3rd and 4th harmonic wave help fill the cylinder WITHIN the ENGINES RPM RANGE
http://www.bgsoflex.com/cgi-bin/intakeln?length=18

BUT shorten the runner length to about 6" like you did by in effect extending the plenum volume down into the base of the intake bye making the runners for all intents just an extention of the plenum and you get this result
http://www.bgsoflex.com/cgi-bin/intakeln?length=6

all the benefits of intake harmonics WELL ABOVE THE RPM RANGE OF THE ENGINE

but look what just shortening the runners by 3" does
http://www.bgsoflex.com/cgi-bin/intakeln?length=15

now Im not saying you won,t get a gain in high rpms, but your low and mid range will cancel most of the gains

the HOLLEY STEALTH RAM has MUCH BETTER air flow (about 280-300cfm) and a cross sectional area that greatly improves the air flow at higher rpms and RUNNERS that are effectively about 11-12 inchs long measured from plenum roof to the back of the intake valve
http://www.bgsoflex.com/cgi-bin/intakeln?length=11 http://www.bgsoflex.com/cgi-bin/intakeln?length=12
_________________

Here's the chassis dyno results!
Car is an automatic 1992 5.7L Camaro. Car is bone stock except cat back.

We added the stealthram and a Holley billet 58mm throttle body. That was the only changes. I don't think the throttle body makes much of a differenece at this power level.

This data is for 3rd gear RWHP on a dynojet.

RPM Stock HP Stealthram HP Diff
3400 190 175 -15
3600 200 188 -12
3800 209 198 -11
4000 210 204 -6
4200 212 210 -2
4400 213 223 +10
4600 214 234 +20
4800 210 240 +30
5000 198 239 +41
5100 184 238 +54
5200 174 237 +63




[Modified by grumpyvette, 7:48 PM 4/18/2003]


[Modified by grumpyvette, 7:49 PM 4/18/2003]

devilfish

hmm interesting..

But when you move to a more agreesive cam you would se more gains with the siamesd base wouldent you?

Do you think its not worth the work on doing the base?
What about this post @ thirdgen.org, that and the info provided by 65Z01 here at the forum that made my go this route?
http://www.thirdgen.org/techbb2/showthread.php?
s=&threadid=47263&highlight=siamese

thanks..

86VETTEMAN

Ok, So instead of the siamese runners, I could get the large runners,Ported stock plenum, and ported stock base. Increase my HP with no loss of low end torque? Any idea if this set up will hinder HP with the 383 set up I previously posted? Seems to me that if I can get near the gains of the Supper Ram or Stealth Ram, why spend that much money? Even if I see a 30 HP gain, $300 in intake mods are half the power and half the money as the Stealth Ram. It's sort of a "Glass half full or half empty" thing. I just want an intake system that isn't going to be the weak link in my performance, like the stock set up and see the power that I want to add, i.e. aroung 500 HP. I know HP costs money, but that doesn't mean I should give in to the demands of rediculous aftermarket prices.

grumpyvette

86VETTEMAN
what your doing by porting the plenum an base and siameseing the first 3" of the upper runner is in effect changing a stock TPI into what a super ram is.... a larger plenum area, with shorter ,slightly larger ports. this as you say is a big help/improvement (230-245cfm) over a standard TPI. from the stock 190cfm-200cfm
a stealth ram flows about ( 275-300cfm depending on the minor cleanup, porting that gets done!) and it further unrestricts the intake ports,
your correct that the siamese runners,ported base and plenum makes a big differance in flow and can make a big improvement , but they are not in the same ball park
lets look at it
standard tpi= about 200cfm, limits you to about 375-420hp if everything else is perfectly matched
SLP runners,$300.accell base $470+ plus porting=$770 for about 420hp-475hp if everything else is perfectly matched
super ram $1328 years of useing that show 425hp-500hp as a good average http://www.jegs.com/cgi-bin/ncommerc...19&prmenbr=361
stealth ram,in a C-4 about $780-$980 depending on how fancy you want to get! but flows enough air to exceed 500hp with the correct matching parts,if you looked at HOLLEYs first dyno results you see a boost of 60+hp on a nearly stock engine, keep in mind that the better flowing the cylinderheads,cam,headers,ETC. you add and the larger the engines displacement the greater the addvantage the higher flow intakes will show on a dyno, and also keep in mind that as those ports get bigger and flow more theres a LOSS in low rpm torque, due to the drop in port,air speeds, thats made up in the higher RPM ranges, due to the lowered restrictions and much higher flow rates

65Z01

86VETTEMAN, for your 383 I was suggesting the siamese base as a possible temporary alternative to the big $$ aftermarket intake setups; if it does the job so much the better and the price is right.

With stock heads & cam I saw a 20hp (10%) gain at 5,400rpm with only a 1"deep cut; haven't had a chance to dyno again after the latest cut to nearly 2" deep. The expected loss of low end torque showed up as a "slight" increase in 60' time at the strip; since I have an A4 the chassis dyno can't show the numbers down there.

I feel the TPI tuning is still in effect as I haven't just moved the plenum into the base but also provided two runners (of nearly stock length) for each cylinder to draw through.

Again your 383 will have loads of low end torque but needs some more air up top so this might be a mod worth considering. It would be interesting to see how dyno pulls with your stock TPI intake compare with those from a siamese base.