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View Full Version : throttle body/ exhaust mani porting?



a_mounty
05-16-2009, 02:39 PM
well i have a friend who has a probe gt....ya ya ya i know why am i talking about a probe on a celi forum????


well i have ridin in his car before and after he modded his throttle body... and it pulls much harder in the upper rpms.... something my car lacks (92 gt 5s)

i know he swapped his stock TB for a ported one off a 5.0......

my question is who has ported there factory TB and what were your results?
what can i expect to gain, if anything?
is there one off a different car that i could swap that would make a difference?
also i was bouncing the idea of porting my exhaust mani in my head....

im looking for the "free" power mods. nothing too extravagant just enough to make a difference and shift the powerband a lil higher....since after all it is only just a 300 dollar car after all ;)

looking for thoughts, comments, concerns, or anything else related to this area.

thanks for your help guys... :wiggle:

Grot
05-16-2009, 02:41 PM
im fairly sure that the 5.0 TB fits on our cars as well.

ciento44
05-16-2009, 03:17 PM
With minor adaptation, yes.

But i believe you want a 7mgte throttle body, since i think the TPS matches.

Will you see a difference? Probably not. The main reason why this engine doesn't breathe up top is because of the head design, not the throttle body.

a_mounty
05-16-2009, 03:47 PM
hmm... thanks for the insight. ill have to further investigate this now.

what all would have to be adapted on the 5.0? tps i think?

grayscale
05-16-2009, 04:44 PM
Yes, you'd need to rewire the tps and do whatever to make the voltage right. The 7mgte tb just needs an adapter.
If you search the user name partyball in the for sale forum he has a 5.0 tb project for sale.

a_mounty
05-16-2009, 05:20 PM
hmm... thanks for that ill def look into it.

i have a buddy ( dude with the probe) that i might pick up his. he says it was bored to 65mm.... but the blade doesnt seal right. so if its salvageable i might pick his up....

Lonestag
05-16-2009, 06:22 PM
Actually, I'm picking up that project.

I'm thinking about throwing it on the 3SFE in my vert.

a_mounty
05-16-2009, 07:03 PM
:/ oh well i prefer do do my own mods any how

best of luck to ya and keep us updated.

anyone ever port the exhaust mani? or is that just a waste of time? lol

Grot
05-16-2009, 09:24 PM
just buy a header.

joe's gt
05-16-2009, 10:47 PM
With minor adaptation, yes.

But i believe you want a 7mgte throttle body, since i think the TPS matches.

Will you see a difference? Probably not. The main reason why this engine doesn't breathe up top is because of the head design, not the throttle body.

I agree with this completely. Your head is the limiting factor here, as is on most n/a engines. Bigger throttle body will yield more in the upper rpm, but only as much as your head can flow, which is why you probably won't notice a huge difference.

a_mounty
05-17-2009, 08:14 AM
ua that was kinda my thought on the header..... i was just looking for the "free" power mod lol

ya N/A sucks..... but oh well

think i might talk to some other people that might have the TB and see what the deal is with it as roman - dude with the probe told me it was basically useless since it leaked so bad it made it have a 1200 rpm idle

i do not want that

thanks for the insigh/ help guys

MrTurrari
05-18-2009, 12:37 AM
The main reason why this engine doesn't breathe up top is because of the head design, not the throttle body.


Your head is the limiting factor here, as is on most n/a engines. Bigger throttle body will yield more in the upper rpm, but only as much as your head can flow, which is why you probably won't notice a huge difference.

That is a myth. The fact the a 5sfe doesn't breath well into the higher RPMs has very little to do with the actual head design. I have seen dynos showing them breath just fine right up to 8500rpms. Mine breaths good up to 7000rpms currently but I still have the stock throttlebody and intake manifold. The things that keep the 5sfe from breathing into the higher rpms are:

1) Cams (#1 by a long shot)
2) Intake manifold
3) Exhaust manifold
4) Exhaust system
5) Throttlebody and intake
6) Valve size (no one has ever taken one up to where this was the limiting factor)
7) Valve angle and chamber design (again not one has ever taken one up to where it actually makes a big difference as far as I have ever seen)

Something else people need to realize is that the 5sfe is a bigger engine. That requires that you run more agressive cams to get the torque into the same RPMs as you would with a smaller motor. That extra displacement shifts the torque to the left from the start and you have to pull it right again if you want your upper RPMs to be strong. The 5sgte guys run into the same problems where they have shifted the torque left and must do things to shift it right again.

CriScO
05-18-2009, 04:44 AM
Actually, I'm picking up that project.

I'm thinking about throwing it on the 3SFE in my vert.
Be sure to keep us updated. I'm waiting until I build my rev 2 head to upgrade mine, but it would be interesting to see how it performs on the stock motor.

RedRkt01
05-18-2009, 04:06 PM
ya N/A sucks..... but oh well

Not for everybody.

ciento44
05-18-2009, 04:13 PM
That is a myth. The fact the a 5sfe doesn't breath well into the higher RPMs has very little to do with the actual head design. I have seen dynos showing them breath just fine right up to 8500rpms. Mine breaths good up to 7000rpms currently but I still have the stock throttlebody and intake manifold. The things that keep the 5sfe from breathing into the higher rpms are:

1) Cams (#1 by a long shot)
2) Intake manifold
3) Exhaust manifold
4) Exhaust system
5) Throttlebody and intake
6) Valve size (no one has ever taken one up to where this was the limiting factor)
7) Valve angle and chamber design (again not one has ever taken one up to where it actually makes a big difference as far as I have ever seen)

Something else people need to realize is that the 5sfe is a bigger engine. That requires that you run more agressive cams to get the torque into the same RPMs as you would with a smaller motor. That extra displacement shifts the torque to the left from the start and you have to pull it right again if you want your upper RPMs to be strong. The 5sgte guys run into the same problems where they have shifted the torque left and must do things to shift it right again.

Hrmmm..... So the throttle body and port matching the manifolds will help significantly, then?

Lonestag
05-18-2009, 07:05 PM
If you have a new set of cams, I would assume Tb and port matching would have a noticable effect.

a_mounty
05-18-2009, 07:56 PM
doing the TB woundt yield a whole lot but it would to a point help some...or atleast that was my school of thought, hence this thread.

also what is your definition of significantly? 1-5 hp or 50 hp? if its 50 then no 1-5 then prolly yes.

im not sure exactly on how much it would make. i just dont want to feel the power drop off after 5300 rpm..... it gives me a rather narrow power band from 3-5300 ish.

ciento44
05-18-2009, 08:10 PM
Throttle body only won't do much for that. It WILL help throttle response, though. :)

MrTurrari
05-27-2009, 09:46 PM
Hrmmm..... So the throttle body and port matching the manifolds will help significantly, then?
Not by themselves. The 5sfe can use a bigger TB once you start making power up past the stock redline. Port matching the manifold helps a little but unless you make it bigger up the whole runner length you will only be making small gains.

My list is in order of the effect they will have on power. The stuff lower down does very little until you are really pushing the limits.

redwolf
06-16-2009, 10:35 PM
There was a company in Calif that I heard of some time back but cant remember the name that would take weird shaped manifolds and such and used an abrasive type clay that they forced through the passages to open them up and polish them. This might be a solution to porting the intake side behind the tb to the head, then port match the runner to the head. Wait, I think its coming to me, "Exude Hone". Could be. Check it out.

joe's gt
06-16-2009, 11:01 PM
^^ yup. Its called extrude honing. I don't think its cheap tho.