Do I need a tubular manifold to reach 350bhp? Also what mods will get me there with a

[kcoles]

I need my car to push atleast 340bhp, but I’m wondering if I really need a new manifold for that? From into I’ve gathered (mainly from hdev website) I’ve so far purchased

-Large FMIC
-Japspeed intake
-Walbro 255 fuel pump
-Nistune type 4 board
-3inch elbow, downpipe and decat, then a -2.5inch cat back that was already on the car, will that be okay or too small?
-ACT HD organic clutch kit (re surfaced flywheel)

What I’m still yet to get
-Boost controller
-Injectors, would “Jecs” 555cc be okay?
-Z32 maf

If there’s anything else I need please throw some suggestions out, or if there is any modifications, reliability mods, anything at all that may help, please pass the knowledge on! Thanks in advance✌️ here’s a picture of the Car



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[kingk]

To be honest I’d say you’d struggle to hit 340bhp with stock turbo, most people top out at around 300bhp. Also if you’re looking for 350bhp the engine should be healthy at very least, so check the compression or look in to forging (not the cheapest). Walbro as you’ve listed, make sure it’s hardwired too. I’d say you’d probably want 3” exhaust all the way through too. With regards to the nistune I’ve never really looked in to the figures they produce or mods required, but for that power I’d say stage 3 is what you be looking for.

Also I’m breaking mine and have a few of the bits you’re after too, pm me if you’re interested

http://sxoc.com/vbb/showthread.php?1...figures/page12

There’s a few figures on that thread with the supporting mods they have as a guide if you need to see what you need for different power levels

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[kcoles]

To be honest I’d say you’d struggle to hit 340bhp with stock turbo, most people top out at around 300bhp. Also if you’re looking for 350bhp the engine should be healthy at very least, so check the compression or look in to forging (not the cheapest). Walbro as you’ve listed, make sure it’s hardwired too. I’d say you’d probably want 3” exhaust all the way through too. With regards to the nistune I’ve never really looked in to the figures they produce or mods required, but for that power I’d say stage 3 is what you be looking for.

Also I’m breaking mine and have a few of the bits you’re after too, pm me if you’re interested

http://sxoc.com/vbb/showthread.php?1...figures/page12

There’s a few figures on that thread with the supporting mods they have as a guide if you need to see what you need for different power levels

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Thanks man, I think I’ll get all but turbo, get as much bhp as possible (without pushing it too far) then might go down the rb25 route. I’ll pm you now dude, thanks for the help!


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[snops]

370 on the standard manifold here, so yes it’s doable.

[kcoles]

370 on the standard manifold here, so yes it’s doable.

Thanks man! That’s what I wanted to hear lol!


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[pointz]

Apex performance have some tubular manifolds in their sale if you did want a mani.

[Mike41288]

The manifold isn't needed for that power, but that that level, it will be a fair improvement to performance and will reduce the spool time of the bigger turbo you will need. Also, if the turbo is coming off, you may as well upgrade the manifold for a quality tubular one as it will save you a lot of time and hassle in the future
A common setup is the H Dev stage 3a with needs a Garrett GT2871R 0.64 and 555cc Nismo injectors, that will make 340 - 360 HP That's the root I'd go for.
Before upping the power, I'd get the engine compression tested to make sure it can take it.

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[hi_im_fil]

The standard turbo will limit you to around 300bhp. To me that looks like the biggest restriction you’ve got

[mr_pea]

Stock manifold is fine for what you want, as already said, standard turbo is the limiting factor as you'll never hit 340bhp with it.

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[kcoles]

Thanks everyone, I’ll be looking into a compression test ASAP, and a bigger turbo then. Really appreciate all the help, thanks again!


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[green_rs13]

I wouldn't both with 555 injectors. just get 740's
I probably wouldn't bother trying to find a z32 maf either and just get a z33 one welded into your intake pipe.

[ANDY black s13]

swap the 2.5 zorst for a 3 inch,many will say 2.5 will do but I bet at that power level you would see a gain on 2.5 v's 3
there is a reason why HKS did an 80/85mm exhaust for the S body for higher power levels
a recent article on exhaust size showed via dyno back to back a supra 2jz at 550 sort of power gained 64 bhp atw's going to 4 inch
sort of destroying the 3 inch will do to 900 that is sometimes quoted

[zeppelin101]

swap the 2.5 zorst for a 3 inch,many will say 2.5 will do but I bet at that power level you would see a gain on 2.5 v's 3
there is a reason why HKS did an 80/85mm exhaust for the S body for higher power levels
a recent article on exhaust size showed via dyno back to back a supra 2jz at 550 sort of power gained 64 bhp atw's going to 4 inch
sort of destroying the 3 inch will do to 900 that is sometimes quoted

Turbo engines are very sensitive to back pressure, but it depends on the turbo used and how biased it is towards low end response. Whatever the natural pressure response vs flow is for an exhaust that pressure is multiplied upstream by the turbo.

The good OEMs are using ~100mm pipes for a ~600hp engine, but they have aftertreatment to worry about as well.

The manifold is a smaller volume than the almost all of the aftermarket items so it's biased towards low speed response. There is a penalty at higher engine speeds but it's not massive.

[kcoles]

Thanks everyone, some really helpful information, I’ll be upgrading to atleast a 3inch Catback before mapping then, maybe a manifold if I have the money spare, but not overly fussed by it. Anyone know where I can get a good compression test in Gloucester?


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[green_rs13]

just buy one

https://www.amazon.co.uk/s/ref=nb_sb...ression+tester

and do it your self.

[kcoles]

I’ve got someone doing it now for £30 so saves the hassle lol


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[ANDY black s13]

imo anyone with a tuned SR on stock pistons needs a comp tester for diagnosing any future running issues, it will soon pay for it's self
best manifold for a gain through out the rev range would be the Tomei un equal length /same design as the OE but flowing lot better CFM's
http://www.jdm-option.com/eng/parts/06_02/tomei.html
there was a H-dev mani for the SR of same design but discontinued now afaik but come up for sale on here
the manifold uses a bracket linking the cylinder head flange to the turbo flange, but the weight of the turbo is still hanging off the engine
the OE turbo elbow has a bolted on support brace bar going to the block,no after market turbo elbows have the fitting/captive nut for the OE brace
so no brace = the weight of the turbo is not supported the mani will crack,possibly the turbo nuts will come loose often as well as the studs can stretch
it needs a brace,a bit of flat steel bar with a slight twist (the thicker and stiffer the better)
between the turbo elbow exit flange and the closest bell housing bolt
I tested this theory and proved it works on CA and SR
CA brace mani (ebay cheap china thing) was still crack free 30,000 miles later https://scontent-lhr3-1.xx.fbcdn.net...4b&oe=5A752297
SR brace thinner version as used a down pipe to gearbox brace as well (same as OE just no rubber block so it's solid)
https://scontent-lhr3-1.xx.fbcdn.net...40&oe=5A7D8461
https://scontent-lhr3-1.xx.fbcdn.net...41&oe=5AAEA23A

Then from another 3 inch V's 4 inch supra thread on power loss, from going from 4 inch to 3 with no changes at all
(the first one I mentioned was a 64 atw gain)

quoted from the thread:
4" 19psi 518/475

change back half of exhaust to 3", thats it. lost 2 psi and a/f went rich.

3" 17psi 425/418

thats 93rwhp and 57rwtq (this is the power it lost)

now, retuning since the back half exh change-

3" 17psi 445/441 tuned back to same a/f as 4"

now comparing tuned to tuned, but 2 psi less thats-

518 - 445 = 73rwhp (re-tuned to correct AFR'S, 3 inch exhaust still causing restriction = 2 psi boost lost)
475 - 441 = 34rwtq

granted, it would have been nice to compare 19psi to 19psi, but the point of the dyno run was to change nothing but the exhaust and see what happens.

http://www.supraforums.com/forum/arc.../t-286895.html

I only play with tuned cars so anything OE is not on my radar,other than everything can be improved,
the above is actual numbers from proper tests on already modified tuned engines were the gains really show up,

and my totally stock 23k miles 14a made 199 atws, then with just a 3 inch cat back fitted (still on OE CATS) it made 239 atw's
highlighting how horrid and restrictive the stock exhaust is

[kcoles]

imo anyone with a tuned SR on stock pistons needs a comp tester for diagnosing any future running issues, it will soon pay for it's self
best manifold for a gain through out the rev range would be the Tomei un equal length /same design as the OE but flowing lot better CFM's
http://www.jdm-option.com/eng/parts/06_02/tomei.html
there was a H-dev mani for the SR of same design but discontinued now afaik but come up for sale on here
the manifold uses a bracket linking the cylinder head flange to the turbo flange, but the weight of the turbo is still hanging off the engine
the OE turbo elbow has a bolted on support brace bar going to the block,no after market turbo elbows have the fitting/captive nut for the OE brace
so no brace = the weight of the turbo is not supported the mani will crack,possibly the turbo nuts will come loose often as well as the studs can stretch
it needs a brace,a bit of flat steel bar with a slight twist (the thicker and stiffer the better)
between the turbo elbow exit flange and the closest bell housing bolt
I tested this theory and proved it works on CA and SR
CA brace mani (ebay cheap china thing) was still crack free 30,000 miles later https://scontent-lhr3-1.xx.fbcdn.net...4b&oe=5A752297
SR brace thinner version as used a down pipe to gearbox brace as well (same as OE just no rubber block so it's solid)
https://scontent-lhr3-1.xx.fbcdn.net...40&oe=5A7D8461
https://scontent-lhr3-1.xx.fbcdn.net...41&oe=5AAEA23A

Then from another 3 inch V's 4 inch supra thread on power loss, from going from 4 inch to 3 with no changes at all
(the first one I mentioned was a 64 atw gain)

quoted from the thread:
4" 19psi 518/475

change back half of exhaust to 3", thats it. lost 2 psi and a/f went rich.

3" 17psi 425/418

thats 93rwhp and 57rwtq (this is the power it lost)

now, retuning since the back half exh change-

3" 17psi 445/441 tuned back to same a/f as 4"

now comparing tuned to tuned, but 2 psi less thats-

518 - 445 = 73rwhp (re-tuned to correct AFR'S, 3 inch exhaust still causing restriction = 2 psi boost lost)
475 - 441 = 34rwtq

granted, it would have been nice to compare 19psi to 19psi, but the point of the dyno run was to change nothing but the exhaust and see what happens.

http://www.supraforums.com/forum/arc.../t-286895.html

I only play with tuned cars so anything OE is not on my radar,other than everything can be improved,
the above is actual numbers from proper tests on already modified tuned engines were the gains really show up,

and my totally stock 23k miles 14a made 199 atws, then with just a 3 inch cat back fitted (still on OE CATS) it made 239 atw's
highlighting how horrid and restrictive the stock exhaust is

Wow fair play, and thankyou for that. My old nuts used to come loose all the time it was so annoying, I’ll deffo have the brace welded whilst it’s all off then. May save up for the tomei manifold then man, thanks a lot!


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[zeppelin101]

i
Then from another 3 inch V's 4 inch supra thread on power loss, from going from 4 inch to 3 with no changes at all
(the first one I mentioned was a 64 atw gain)

quoted from the thread:
4" 19psi 518/475

change back half of exhaust to 3", thats it. lost 2 psi and a/f went rich.

3" 17psi 425/418

thats 93rwhp and 57rwtq (this is the power it lost)

now, retuning since the back half exh change-

3" 17psi 445/441 tuned back to same a/f as 4"

now comparing tuned to tuned, but 2 psi less thats-

518 - 445 = 73rwhp (re-tuned to correct AFR'S, 3 inch exhaust still causing restriction = 2 psi boost lost)
475 - 441 = 34rwtq

granted, it would have been nice to compare 19psi to 19psi, but the point of the dyno run was to change nothing but the exhaust and see what happens.

http://www.supraforums.com/forum/arc.../t-286895.html

I only play with tuned cars so anything OE is not on my radar,other than everything can be improved,
the above is actual numbers from proper tests on already modified tuned engines were the gains really show up,

and my totally stock 23k miles 14a made 199 atws, then with just a 3 inch cat back fitted (still on OE CATS) it made 239 atw's
highlighting how horrid and restrictive the stock exhaust is

Kind of an unfair test since they didn't see what the turbo impact really was of running the same boost pressure? Yes, the restriction changes and if you do nothing with the wastegate then of course the boost pressure will drop but the real point is that... You have a wastegate! Retune it to the same boost pressure and then see what the impact is from the increased pre turbine pressure on ignition and pumping loss. It is unlikely to be any where near the numbers quoted unless the turbo is on the raggedy edge.

Changing nothing but the exhaust is not a fair test at all. Either fix the boost pressure and measure output or fix the output and measure boost pressure / AFR / ignition differences. Just changing the exhaust and suffering the loss of boost and saying it's cost loads of performance is ridiculous no?

If I put that test data in front of my boss I'd be getting slapped and told to do it again!

[ANDY black s13]

Kind of an unfair test since they didn't see what the turbo impact really was of running the same boost pressure? Yes, the restriction changes and if you do nothing with the wastegate then of course the boost pressure will drop but the real point is that... You have a wastegate! Retune it to the same boost pressure and then see what the impact is from the increased pre turbine pressure on ignition and pumping loss. It is unlikely to be any where near the numbers quoted unless the turbo is on the raggedy edge.

Changing nothing but the exhaust is not a fair test at all.

If I put that test data in front of my boss I'd be getting slapped and told to do it again!

they re-tested with AFR'S corrected and the exhaust still causing the 2 psi of boost pressure lost and it was still a 74 whp loss in power
I agree a test at 19 would be ideal, but I'm not seeing that just 2 psi and regaining all that power with the power curves mirrored
another 2 psi I estimate around 35>45 maybe 50 doubtful as high as 74 and the more important lb-ft's all restored
so he did high light that untested just swapping the exhaust it affected boost and AFR's a lot,
like it dropped to 10 or the lowest it could read as a caution to others swapping exhausts on the forum

the other test I mentioned was a gain of 64 whp iirc 55 lbft uncorrected going 3 > 4 ,it may well be that was the same with AFR'S were way off ?
and could have made further gains when corrected, but they didn't mention any further testing just the straight swap
and back to back testing same day no other changes like a diy mechanic would and it's affects was the theme in both tests tbh

I know its nothing to the proper testing of your very high standards ,
he mentioned turbo spec in the 3>4 test as a SP67 P trim and I have no idea what it's capable off
that's more your area of knowledge with efficiency maps for a given turbo