Intake Question Opinions Wanted
Thread Starter
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
Intake Question Opinions Wanted
What benefits if any would I see from using this part on my 87 L98 stock engine. Only mod is cut air box lid.
Fully ported TPI upper intake plenum, Throttle body opening is 58mm and completely recontoured, all casting intrusions removed. The runner exits are Siamese for use with SLP runners.
Fully ported TPI upper intake plenum, Throttle body opening is 58mm and completely recontoured, all casting intrusions removed. The runner exits are Siamese for use with SLP runners.
Thread Starter
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
I should of listed I have a cat back free flowing system new bosch lll's plugs wires cap rotor filters car runs great
Last edited by floridamale; Jul 22, 2008 at 08:59 PM.
Team Owner
Joined: Oct 2006
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16-'17
NCM Member '09
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
spend your time porting the intake, and or runners,,,
If you port the base and siamese the base runners to a depth or 1"-2" you will not lose much low end but will gain noticible top end power, check out the before/after dyno pulls on my site.
Instructor
Joined: Dec 2005
Posts: 142
Likes: 2
From: Centerport NY
I have a similiar setup with megaported siamesed SLP runners which were port matched to the mega ported siamesed plenum -1990 L98.
Some other cheap mods are the Adjust. Fuel pressure reg to 45 psi, Taylor wires, TB bypass, K&N Air filter, tossed frisbee, 180 thermostat, catback magnaflow exhaust and an aftermarket chip.
When I went with the plenum/SLP set up I did not change the intake manifold because the heads don't flow more than about 185 cfm with a stock cam and the stock intake manifold flows better than that -meaning no matter how much air the intake system supplies, the heads are now the flow restriction point.
Anyway - the mega ported SLP system works great. You will definitely lose a little low end torque but it realy wakes the car up from 2000 rpm on up. The stock TPI torque/power wall @ 4500rpm goes away and the car pulls strong to about 5500 rpm.
Some threads have suggested siamesing the intake manifold which
maitains the low end torque and pushes the upper rpm limit. You might want to consider that.
Personnally I thought the megaported system was worth it and if I ever go to a cam and heads for some significant gains I'll decide then what intake I will use.
Good Luck!
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Instructor
Joined: Dec 2005
Posts: 197
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From: Woodland California
I have the accel super ram with the accel base on a stock 86. The 58mm TB killed low end tork. With the stock TB there is much more low end than the stock intake. The 58mm is for modified engines (larger displacement, heads & cam) I agree the heads are the limiting factor, but you should notice more tork with the bigger base, & siamesed runners. Port matching also helps. Exhaust helps as well. Bigger gains will come if/when you add bigger heads & cam. Google Guildstrand grand sport 80, and check out his early C4 mods.