Devilfrog
NAXJA Forum User
- Location
- Duncan, BC
been running a lightly modified Renix/HO 4.0 for the last year or two (time flies) in my Comanche
I used a 92 head, 99+ intake manifold, 94 fuel rail and Volvo 746 injectors, a 94 4.0 throttle body, 94 exhaust manifold, and 96 power steering pump. Think that covers most of it.
Even with literally shaveably polished cylinder walls, and a noticeable oil burn at cold start, yeah she's tired, I can now spin my 32" ish JK take offs (255/75r17) at will with 3.07 gearing in first. Something I couldn't do with the stock head and intake/exhaust on 235/75r15's before hand.
About the only thing I'd change ... besides rehoning the damn motor - sudden onset time constraints canned that plan ... and the point behind this post, would be a smaller throttle body.
In fact I'm thinking of trialing a 2.5L Throttle body shortly.
With the Renix values plugged into a Throttle Body size calculation and a power TQ) peak at 3400 (something I have yet to go past) ... I calculated a need for a measly 48mm throttle body for full range power.
The 58mm stock 4.0L TB pushes the curve further out the line and is actually something I have noticed on the highway, a fair lag below 1800rpm in higher gears where the motor works harder and the TB is open more. This is exacerbated by the 3.07 gearing as well. But I experienced a similar issue when I swapped a 4.0 TB onto my old 2.5 YJ years back ... Kinda makes one think.
I'm going to try swapping a 2.5L Throttle body on for S&G's to see what happens with a 52mm TB in place. If it works, great, if not, swapping back is easy as pie. Been curious about it for sometime actually, might as well scratch that itch. There is a diminishing return on TB size, and with the larger volume of the later intake plenum (IIRC it 4300cc vs 2600cc volume) there is some food for thought there.
Anyone have any thoughts to add? Am I barking up a wrong tree? Been sniffing to many exhaust fumes? Or am I actually onto something?
The GM 2.8L TPS swap I did a while back started this way as well, and works like a hot damn for 1/4 the price. Who's to know if we don't at least try.
Just thought I'd ask the more knowledgeable for any input on the idea ....
Thanks for any advice, thoughts, direction.
I used a 92 head, 99+ intake manifold, 94 fuel rail and Volvo 746 injectors, a 94 4.0 throttle body, 94 exhaust manifold, and 96 power steering pump. Think that covers most of it.
Even with literally shaveably polished cylinder walls, and a noticeable oil burn at cold start, yeah she's tired, I can now spin my 32" ish JK take offs (255/75r17) at will with 3.07 gearing in first. Something I couldn't do with the stock head and intake/exhaust on 235/75r15's before hand.
About the only thing I'd change ... besides rehoning the damn motor - sudden onset time constraints canned that plan ... and the point behind this post, would be a smaller throttle body.
In fact I'm thinking of trialing a 2.5L Throttle body shortly.
With the Renix values plugged into a Throttle Body size calculation and a power TQ) peak at 3400 (something I have yet to go past) ... I calculated a need for a measly 48mm throttle body for full range power.
The 58mm stock 4.0L TB pushes the curve further out the line and is actually something I have noticed on the highway, a fair lag below 1800rpm in higher gears where the motor works harder and the TB is open more. This is exacerbated by the 3.07 gearing as well. But I experienced a similar issue when I swapped a 4.0 TB onto my old 2.5 YJ years back ... Kinda makes one think.
I'm going to try swapping a 2.5L Throttle body on for S&G's to see what happens with a 52mm TB in place. If it works, great, if not, swapping back is easy as pie. Been curious about it for sometime actually, might as well scratch that itch. There is a diminishing return on TB size, and with the larger volume of the later intake plenum (IIRC it 4300cc vs 2600cc volume) there is some food for thought there.
Anyone have any thoughts to add? Am I barking up a wrong tree? Been sniffing to many exhaust fumes? Or am I actually onto something?
The GM 2.8L TPS swap I did a while back started this way as well, and works like a hot damn for 1/4 the price. Who's to know if we don't at least try.
Just thought I'd ask the more knowledgeable for any input on the idea ....
Thanks for any advice, thoughts, direction.
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