Ported Throttle Bodies + CSL airbox.

[JeremyJames]

I am looking for feedback on ported throttle bodies paired with a CSL style airbox. Is the porting worth the gains in addition to the box?

After cracking into the intake side to replace the starter, I ended up removing the entire throttle body rail in effort to clean the ITBs, service the injectors and vacuum rail, replace orings and springs, etc. I do not plan on doing this ITB service myself, nor do I know anything about ITB synchronizing.

So at this stage, with them off, in addition to a Karbonius en route, I am wondering if the move is to order the VAC ported throttle bodies (or other?), which is a service that would be performed on my already removed and already in need of service throttle body rail.

This car will always remain N/A as I have zero plans to boost this car.

Any knowledge on this set up would be greatly appreciated I wasn’t able to find much info on both CSL+ported ITBs or even which company provides the best quality/proven porting service.

[jet_dogg]

Are throttle bodies even worth doing? I can't imagine much of a benefit boring out ITBs, single tb sure but I'm not so sure it'll be worth the effort.

I could be wrong though.

[Tbonem3]

Are you at the end of your modding journey basically? That's a lot of $ better spent on 100 other things imo

[digger]

Pick all low hanging fruit first

[Mr.wReckless]

Dinan do a bigger TB I think, but in general I thought porting was for the intake side of the head, i.e after the TB's and before the valves. You haven't removed the head have you?

Regards

[JeremyJames]

So my actual dilemma is, I have all of my ITBs off and they need a major overhaul. Injector orings are leaking, vacuum rail connector orings are leaking, the springs for each flap are 100% in need of a replacement they are dry and gritty, carbon build up needs cleaning. So the entire rail needs a service/overhaul. I literally cannot find this service that exists.

So my thoughts were, essentially, this service does exist with VAC and Dinan but they add the bore.

I agree, there are better mods for the money, however I am trying to do what makes sense with ITBs while I have them off of the engine ready for a rebuild.

[digger]

Vac throttles are almost 2k

yours need a clean and some seals sounds fairly straight forward

hell a good used set and spend the rest on hookers and coke

[Cubieman]

I would do the "dirty" work yourself and you'll thank yourself latter when you want cams/etc. Even with a matching tune I think it is generally understood the bigger TBs are going to have negligible gains at best.

As far as leaky injector orings, buy some new orings/have your injectors cleaned, or just buy new injectors. The air rail orings are available for purchase, simply replace those guys and you're good to go.

Since you have the ITBs out, I would think with the right products you could get it extremely clean. Brake cleaner for the carbon buildup, maybe some simple green others places. Might even be able to hot tank it if you want it to look like new, just make sure there aren't any parts that would melt, such as the little black plastic caps.

It sounds like you want to get a new/exciting part (I know) since you have the current ITB assembly removed, but just clean up what you've got and save the cash unless it ain't no thang.

[Obioban]

Nick P did a before/after dyno with them as the only change, with a tune optimized for each. With every other bolt on mod under the sun done (IIRC it was 376 SAE dynojet rwhp), the difference was 6-7hp at high rpm, and slightly less hp than stock at low RPM. If your car is making less power, the gains from them will be less (as they're less of a restriction point).

They are probably the worst bang/buck of all the NA mods that actually can gain power.

... He took them off.

[JeremyJames]

I would do the "dirty" work yourself and you'll thank yourself latter when you want cams/etc. Even with a matching tune I think it is generally understood the bigger TBs are going to have negligible gains at best.

As far as leaky injector orings, buy some new orings/have your injectors cleaned, or just buy new injectors. The air rail orings are available for purchase, simply replace those guys and you're good to go.

Since you have the ITBs out, I would think with the right products you could get it extremely clean. Brake cleaner for the carbon buildup, maybe some simple green others places. Might even be able to hot tank it if you want it to look like new, just make sure there aren't any parts that would melt, such as the little black plastic caps.

It sounds like you want to get a new/exciting part (I know) since you have the current ITB assembly removed, but just clean up what you've got and save the cash unless it ain't no thang.

The orings are cake easy. My main concern is the 6 springs for the flaps. They are gritty and corroded. Oil will not be a fix. I don’t know jazz about the ITB rail, but if I understand correctly — the rail will have to be broken down and the ITBs will have to be synchronized. I like challenges, but I don’t want to go down that rabbit hole.

My first attempt was to send them off for service, but there is a lot of lacking info on the S54 ITBs I don’t see where anyone accepts this as a service for you to send in your rail. I’m not aware of a good trustworthy shop and this is why I perform my own maintenance. I am not necessarily needing to mod but my thought process was, if it makes sense I can slap rebuilt, clean beautiful ported ITBs. It doesn’t sound like there is any gain to this so now I’m back to square one haha.

[JeremyJames]

Nick P did a before/after dyno with them as the only change, with a tune optimized for each. With every other bolt on mod under the sun done (IIRC it was 376 SAE dynojet rwhp), the difference was 6-7hp at high rpm, and slightly less hp than stock at low RPM. If your car is making less power, the gains from them will be less (as they're less of a restriction point).

They are probably the worst bang/buck of all the NA mods that actually can gain power.

... He took them off.

I appreciate this info. This basically solidifies it’s absolutely not worth porting ITBs. Thank you.

[BBRTuning]

I tested one of the two prototype 52.5mm shaftless billet throttle kits for the S54, made by ATPower, and found exactly zero power gains. This was done back-to-back on my personal car which I mapped myself (standalone ECU) which at the time was making ~355whp Dynojet (CSL box, 288/280, SSV1s, built bottom end, etc) although I did have factory unported head. Their shaftless throttles still use a 50mm bore but the removal of the shaft in the airstream increases the effective area to over 52.5mm (stock is 50mm) while not requiring any head porting to port match. I could see some small gains with a well ported head, particularly exhaust side, and/or a stroker engine, but even on my "heavily bolt-on" engine, there was zero gain. Same results were reported by their other tester in the UK. They did look beautiful, though!

Syncing the throttles isn't too bad. You'll need a carb synchrometer, something like the Redline Synchrometer, and the factory throttle setting document. Since I'm unable to attach PDFs, search "13 54 010 Adjusting basic throttle setting (S54)" on google and you'll find it.

[duracellttu]

I tested one of the two prototype 52.5mm shaftless billet throttle kits for the S54, made by ATPower, and found exactly zero power gains. This was done back-to-back on my personal car which I mapped myself (standalone ECU) which at the time was making ~355whp Dynojet (CSL box, 288/280, SSV1s, built bottom end, etc) although I did have factory unported head. Their shaftless throttles still use a 50mm bore but the removal of the shaft in the airstream increases the effective area to over 52.5mm (stock is 50mm) while not requiring any head porting to port match. I could see some small gains with a well ported head, particularly exhaust side, and/or a stroker engine, but even on my "heavily bolt-on" engine, there was zero gain. Same results were reported by their other tester in the UK. They did look beautiful, though!

Syncing the throttles isn't too bad. You'll need a carb synchrometer, something like the Redline Synchrometer, and the factory throttle setting document. Since I'm unable to attach PDFs, search "13 54 010 Adjusting basic throttle setting (S54)" on google and you'll find it.

Great info. I have a similar build and debated Dinan TBs since I was doing all the same maintenance as OP. This convinced me that it isn’t worth pursuing even thought I have a ported exhaust side on my head.

[old///MFanatic]

Their shaftless throttles still use a 50mm bore but the removal of the shaft in the airstream increases the effective area to over 52.5mm (stock is 50mm) while not requiring any head porting to port match. I could see some small gains with a well ported head.. but even on my "heavily bolt-on" engine, there was zero gain.

Interesting, the way you describe the throttle bodies it seems about right it would not offer gains. Unless I’m reading it wrong they’re basically not enlarged for air flow compared to a bored out t-body.

[Anri]

HI,


I also run 52mm ITB.



A year later after 52mm were installed I flow benched the S54
cylinder head in order to get more juice on my next build for my
customer/s.

I also did flow bench the stock 50mm ITB.


I wish I did the test the way around.


Regards,
Anri.