Shorten runners L28et

[woldson]

I have a 83 turbo engine, p90a, f54.

I'am not an expert on flow, (read alot, bit confusing) anyhow, the intake manifold is so combersome to work around.

So I'am thinking of mabey a tt set up with squirll turbos off the stock ex. manifold and mabey 300-400hp.

I'am not trying to re-invent the wheel, just wondering if I can considerable shroten the runner w/o takeing a bit hit on performance.

 

I'am only doing this to make "getting" at stuff easier.

[ShaggyZ]

I have a 83 turbo engine, p90a, f54.

I'am not an expert on flow, (read alot, bit confusing) anyhow, the intake manifold is so combersome to work around.

So I'am thinking of mabey a tt set up with squirll turbos off the stock ex. manifold and mabey 300-400hp.

I'am not trying to re-invent the wheel, just wondering if I can considerable shroten the runner w/o takeing a bit hit on performance.

 

I'am only doing this to make "getting" at stuff easier.

 

I'm considering something similar. If you're going to heavily modify the intake manifold, consider tilting it up a bit away from the turbo and manifold. For a turbo vehicle, take a look at the aftermarket manifolds for 2JZ's, RB's, etc. - they're all very short runners and have larger, wedge-shaped plenums. I might just find some "decent" aftermarket chinese manifold like those and modify it to fit the stock Datsun runners.

[woldson]

Yes I've seen a few of them.

I looked today at my intakes and figured I can only take off mabey an inch or so. Hummm.

 

Ether I'am going to leave it alone or "molly be danged" and put something together that makes sense to me and hope that I atleat break even.

[Challenger]

Ive got an extra turbo manifold that Im wanting to experiment on also... I was actually thinking about making a curved one like the ld28 and where it is the same height and same runner length (maybe longer) but doesnt stick out as far.

 

I was also considering mounting the turbo on the passenger side... that might be something to experiment with. It would really free up some space on the driver side.

 

Also do you have a tig at your shop? That would really help if your wanting to work with the aluminum.

[woldson]

My brother in low has every welder in his shop.

I was thinking, why not just make it all tubes all the way to the throttle body?

Two on top, two in middle and two on bottom? Keeping the tubes really close to the head?

[Challenger]

My brother in low has every welder in his shop.

I was thinking, why not just make it all tubes all the way to the throttle body?

Two on top, two in middle and two on bottom? Keeping the tubes really close to the head?

 

Without a plenum? Would the runners go strait into the TB? Cnat really picture this..

[woldson]

Just enough to make the adaption of tb to the intake pipes. I'll post a pic later of something that is kinda where I got my idea from.

[Daeron]

are you talking about two 3->2 collectors mounted directly to the throttle body, not dissimilar from six exhaust runners merging just before a turbo flange? Interesting idea, but I think you might encounter more eddies and impedances from the bending of the runners than an intake charge should be subjected to.

 

The stock manifold is far too much of an impedance (runner diameter) to even bother with modifying. An LD28 manifold would be worth tinkering with, and some have. If you want to play insane games, there is the SU EFI manifold setup like what Z-ya has posted in the "Fuel" subforum.. or you could just buy a Lone Wolf intake or something similar. He re-used the flange from a stock EFI manifold... but the entire rest of his piece was made from an SU intake manifold, and he mounted two stock TBs onto it in place of SU carburetors. Add fuel rail and voila!

 

 

Many have said that the intake manifold is one of the chief places to massage on an EFI L28, especially with a turbocharger. There is one manifold in the works that has had some SERIOUS computer development go into it; Personally I cannot WAIT to hear power results from it. (Not to mention the accompanying tuned exhaust note!)

[Tony D]

Without a plenum? Would the runners go strait into the TB? Cnat really picture this..

 

Take a look at some of the newer Toyota Manifolds, they look just like that: a set of Tube Headers with a T/B stuck on the 'collector flange' and made of aluminum instead of steel.

[Tony D]

The stock manifold is far too much of an impedance (runner diameter) to even bother with modifying.

 

That was why JeffP limited himself to simply extrude honing it and smoothing it out a bit. It was recognised it would be the necking point on his system, and is really restricting his output right now. He's only making 600Hp, so if you are shooting for more than that, to be sure the stock manifold will probably really prove to be an impediment.

[Daeron]

That was why JeffP limited himself to simply extrude honing it and smoothing it out a bit. It was recognised it would be the necking point on his system, and is really restricting his output right now. He's only making 600Hp, so if you are shooting for more than that, to be sure the stock manifold will probably really prove to be an impediment.

 

ohhh, shutup.

 

any time anyone quotes a piece of widely accepted lore that jeffp's car refutes, you chime in.... you dont HAVE to do it dripping with sarcasm...

 

 

(just to make it abundantly clear, this entire post is tongue-in-cheek because I always forget he is running the stock piece there. For the record, I would KILL to see what simply swapping say, Monzter's ITB plenum for the stocker would do for numbers. Naturally the tune would likely need to be changed, but you get my point)

[woldson]

Seiously I'am only looking at makeing it easier to get at the stuff I put underneth it, with out hindering performace.

I read some other threads recently and I might have found a problem with my desingn. I wanted all the runners to essentialy to take a 90 out of each intake port and head to the frount of said engine. The problem is that no1 intake would be very short and no6 very long.

I believe this to be maby a bad thing.

Remember I'am not trying to highly sopisticated on this just don't want to screw my self an a bounch of work.

The fun part is that I have a running ZX and can build at my lesiure.

Only shooting for 350rwhp with a couple of squrill turbos off the stock manifold (if I can fit them). (not intandam but side by side.)

[Daeron]

adding a 90 degree bend would just hurt the airflow into the engine anyhow. One thing you COULD do, I suppose (someone else please support me or shoot me down on this one) would be to machine the flange of the stock intake manifold at a slight angle to raise the log of the plenum up a bit from the stock position. There wouldn't be much of an angle you could machine before reaching a limit of "wise-ness," so you couldn't change a whole lot by way of hood clearance.. but it might work/be worth it?

[woldson]

So I was thinking it over and came up with a diff idea.

I've got a set of su intake runners and if I can clear the hood, I can extend the back of the runners and essentally open the balencer tube hole up to X size on both runners.

This way I can a box on top that will span both. So the runners will only be about 2inchs longer than stock and the manifould will be on top to match.

Hope that was clear enough.

Also I wll use the flange from stock manifold for the injector holes unless it is easer to build them on the su instead.

[X64v]

Take a look at some of the newer Toyota Manifolds, they look just like that: a set of Tube Headers with a T/B stuck on the 'collector flange' and made of aluminum instead of steel.

 

We had one come through the shop today. Remembering this thread, I snapped a picture on my phone. The runners appear to be equal length.