| MayanArch |
Posted
Tuesday, Nov 6th 10:43pm [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 1436
Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978 |
Its pretty well established that an E30 "i" intake is much more free flowing than an E30 "e" intake.
How does the 323i E21 intake compare with the E30 "i"intake as far as flow?
Can you use an E30 "i" intake with a K-Jetronic fuel system? I dont see that the E30 intake has the cold start and cold air auxiliary ports.
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| TJ |
Posted
Wednesday, Nov 7th 7:09am [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 43
NY, USA
82 528e2i 84 320i/4 80 320i |
The e30 had three different intakes the 325e, 325i, and 323i. I hear the 323i manifold is actually a bit better than the 325i manifold for top end power. The e21 manifold has the smaller runners for the intake ports of the old 200 head, although it's probably better than the e manifold.
On the 325i manifolds, the area where the cold start valve is on the 325e just has a cover bolted on with a single small pipe for the FPR vacuum hose. You can replace it with the part from the 325e if you want to have the cold start valve (and also the pipe for the idle control valve in the old location)
I wonder if the k-jet injectors would fit properly in those manifolds though, or if there would be any difficulty routing the fuel lines. |
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| MayanArch |
Posted
Wednesday, Nov 7th 1:46pm [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 1438
Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978 |
| TJ wrote: | The e30 had three different intakes the 325e, 325i, and 323i. I hear the 323i manifold is actually a bit better than the 325i manifold for top end power. The e21 manifold has the smaller runners for the intake ports of the old 200 head, although it's probably better than the e manifold.
On the 325i manifolds, the area where the cold start valve is on the 325e just has a cover bolted on with a single small pipe for the FPR vacuum hose. You can replace it with the part from the 325e if you want to have the cold start valve (and also the pipe for the idle control valve in the old location)
I wonder if the k-jet injectors would fit properly in those manifolds though, or if there would be any difficulty routing the fuel lines. |
Is the E30 tuned more for top end. I know that the 325i was pretty quick, but I dont know how it compared 0-60mph to an e21 323i.
What are they tuned for?
Can the "i" injectors be put into the K-Jet system? It seems it would be easier to modify hoses than the cast manifold.
The whole question being for a way to do the 2.7 stroker, but keeping the K-Jet on there and swapping only the block, head, and manifold. |
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| TJ |
Posted
Thursday, Nov 8th 8:01am [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 44
NY, USA
82 528e2i 84 320i/4 80 320i |
Yes I think the e30 323i and 325i had the powerband in a slightly higher RPM range.
All the e30s use electronic injectors, so they're functionally different than the pressure-activated K-jet ones.
You could just use the 2.7 bottom end and keep everything else original. Otherwise, why not get the later head, intake, and Motronic along with it? |
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| MayanArch |
Posted
Thursday, Nov 8th 4:55pm [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 1442
Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978 |
| TJ wrote: | Yes I think the e30 323i and 325i had the powerband in a slightly higher RPM range.
All the e30s use electronic injectors, so they're functionally different than the pressure-activated K-jet ones.
You could just use the 2.7 bottom end and keep everything else original. Otherwise, why not get the later head, intake, and Motronic along with it? |
I like a power band in the lower part of the RPM's for fun daily driving. I dont do much highway, and never race my cars on a track.
I have always loved the response from an E21 323i, and would like to see if that can be maintained by adding more torque with the 2.7 block.
Instead of porting it an E21 head.....using the already better breathing "i" head........and then making headers that will be tuned for a peak power lower down on the RPM range.
I like accelerating out of turns and responsiveness while shifting. Going as fast as you can on a freeway straight-away...well, not as fun for me.
I guess another way of putting the question is......does the shorter length runners from the E21 intake make for more responsiveness lower down in the RPM power band??? and vise versa....do longer runners make for better power at the higher end RPM range, and is that why the E30 runners are longer? |
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| aussie323i |
Posted
Friday, Nov 9th 3:18am [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 595
australia
1979 323i |
I run an ETA manifold with my 323i... Marquis Rex calculated for me a while ago that this moved the torque peak down on my 323i to 3500RPM (vs 4600rpm stock) due to the extremely long inlet runners on the manifold.
Obviously, with the peak torque at lower revs, the peak power will have also suffered on my engine, but in daily driving, this is not such a problem as the engine has more torque at lower revs.
This actually made my 323i feel much more lively with the automatic transmission because I rarely revved it past 4500rpm... BUT since going over to the manual transmission, I have a noticable power drop-off at 5500rpm. This never was the case with the original manifold, which would allow the engine to pull hard all the way to the redline.
If I eventually get some time to put back into the 323i again, I am going to swap the ETA manifold for an e30 323i manifold I have in the shed as a) my 200 head is ported to the point that it will go fairly close to port matching the e30 manifold, and b) I found the car more enjoyable to drive with the revvier nature of the stock manifold.
sorry for the LOOONNNGGGG post, but they are my experiences with the different manifolds!  |
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| MayanArch |
Posted
Friday, Nov 9th 5:28am [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 1444
Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978 |
| aussie323i wrote: | I run an ETA manifold with my 323i... Marquis Rex calculated for me a while ago that this moved the torque peak down on my 323i to 3500RPM (vs 4600rpm stock) due to the extremely long inlet runners on the manifold.
Obviously, with the peak torque at lower revs, the peak power will have also suffered on my engine, but in daily driving, this is not such a problem as the engine has more torque at lower revs.
This actually made my 323i feel much more lively with the automatic transmission because I rarely revved it past 4500rpm... BUT since going over to the manual transmission, I have a noticable power drop-off at 5500rpm. This never was the case with the original manifold, which would allow the engine to pull hard all the way to the redline.
If I eventually get some time to put back into the 323i again, I am going to swap the ETA manifold for an e30 323i manifold I have in the shed as a) my 200 head is ported to the point that it will go fairly close to port matching the e30 manifold, and b) I found the car more enjoyable to drive with the revvier nature of the stock manifold.
sorry for the LOOONNNGGGG post, but they are my experiences with the different manifolds! |
Yeah, the ETA engine configuration has a power band that dies out really quickly. Too quickly for my taste.
I dont get it? The "i" intake has pretty long runners.....albeit a larger diameter interior. The ETA intake is probably 60% of the "i" intake interior diameter by my estimation.
What is the rule of thumb? Longer runners = lower power curve? Shorter runners = higher up power curve? |
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| TJ |
Posted
Friday, Nov 9th 7:46am [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 45
NY, USA
82 528e2i 84 320i/4 80 320i |
That would be the correct rule of thumb. I believe it has to do with the timing of the intake valves opening/closing vs. the speed and volume of air and the length of the runners. So there is some kind of resonance that occurs at a certain RPM and gets extra air moving through there. It would happen at a higher RPM with a shorter runner.
On my 2.7i with the 325i head and intake, the torque peak seems to be a low-ish 3900RPM. It's a big surge that comes on pretty quick though, the curve is not very flat. Right now I'm using the stock 25yr old exhaust, not sure how that figures in, other than perhaps holding back the top end HP. A guy in a pickup with a 200hp Toyota Supra I6 was able to catch up and get ahead in a 1/4 mile after I beat him off the line. |
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| BruceH |
Posted
Friday, Nov 9th 2:34pm [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 1160
Atlanta, GA USA
81 323 Baur, 85 745 |
| MayanArch wrote: | [quote=TJ]
All the e30s use electronic injectors, so they're functionally different than the pressure-activated K-jet ones.
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I thought the euro e30 323 was still kjet? |
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| imaradiostar |
Posted
Friday, Nov 9th 3:52pm [Edit] [Quote] [IMS] [View car] |
Member
Post nr. 1088
Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i |
The euro E30 323i had an ecu that said "jetronic" but it was L-jetronic using electronic injectors and a flapper type air flow meter.
jamie |
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