Why has no one else mounted throttle bodies?

This might be a part of a new gothspeed design project. Or not. I'm just saying...

 

These are the pistons that Sy's LM engine and my IMSA 348 engine use, a Cosworth built piece of the same bore as OE.

When it comes to a custom built engine, be it Race or Street, there are as many opinions as there are options. None are "right" and none are "wrong"... they just "are" BUT, there are fundamental baselines that cant be ignored that few factor in. No matter what is done or what direction is chosen, it WILL be an Exercise in Compromise and the project must be fully planned out prior to the start of widdling..... been there a few hundred times in the past.

I have two engines for the IMSA 348, the Sprint engine and the Enduro engine, one making 100HP more than the other but with a life span of single digit hours between freshening. My plan for this winter is to freshen the Enduro engine and make the car semi streetable for FCA road tours in the mountains.... 'semi' being the key word.... hell, 'this winter' being the other key words as that has been the plan for 3 years now.

Hyenahf touched on one such baseline, most would be surprised at how much power can be made with a stock intake IF everything else down stream is correct.... its all a system and must be designed and built as such. Is it a Bonneville Straight liner where HP is needed, a Road Race car where torque wins at most any track, or a Stoplight screamer? They all require a completely different design. If that doesn't complicate things enough, you have the likes of Muleskinner Bruce hanging Panzer hair dryers on the Red Sleds and taking Cheating to a whole new level. When you cant make power the proper way... hang a hair dryer on it.

Remember one thing throughout this discussion Jerry......... The First liar at the bar never stands a chance! The Bruce's have both showed their hands.... What's that tell ya?

 

Yah... look who is talkin!

Remember, I removed a slide valve intake from the Sprint engine as it limited the driveability on the track. Velocity, one of the fundamentals, and I had a choice to make close ratio gear sets, install a Hewland or widen the torque band. The slide valve worked great from 8700 to 10K BUT..... my race car budget no longer allow's for Big Bang testing.... Im getting too old for that shlt!

 

John Houghtaling of FCRA seems to be a very serious guy. Too bad you or one of the Bruces did not know him better. Maybe we could settle all our lying with the inaguarl GFRT race as a sideshow under his FCRA banner. Have you heard of "Lemons" racing? That's us in Ferraris with driver age minimums.

 

Since you are coming from the world of NSX, undoubtedly you've seen the ITB setup that Science of Speed has developed. Expensive, but from initial reviews it appears to generate HP results on mildly modified engines. Good luck on your project!

 

I have.. and thank you.

 

Dude, anytime you want to connect and go over my past trials on this subject, I'd be happy to do it. Maybe a co-op is in the making. We have been looking at this subject for many years and have yet to come up wit something that is robust, documentable, smog legal, retro-installable, appears stock and gets us some decent results. I believe that I am part way there. I ran out of energy when I got to the possibility of changing out the entire intake system for a different design. At the time I was considering a TB conversion (either 355 or Weber-style semi custom) or a 360-style with a single larger TB per side and redesigned plenum. The potential cost for undetermined results was not attractive. We have lots of annectodal evidence, but so far I have seen absolutely nothing documenting what can be done with these engines by merely changing the intake system.

Case in point: the fabulous 358 Roush prepared (allegedly) race car motor. It was dynoed at 265-ish rwhp or so. That's more than my 254 rwhp but far less than the 302 we saw on goth's 355 prepped engine. We can't spin the 358 motor at 8500 rpm, but our test ended at 7500 so we need to test it now that we upped the red line to 8000 with Dave's okay. This motor uses stock intake design so far as we can determine. I have not "miked" the TBs so they might be bored and I am pretty sure someone did a port and polish on the airboxes and runners (was that your handywork Dave?). Still this car is frighteningly fast. This is what a weight loss program, free flow exhaust and custom gear ratios get you. I should say that the injectors are not stock and are about twice the capacity of stock. I have no reason why that was done except that maybe using stock ones put them at jeapordy of failure due to duty cycling given the track use.

 

265 is a very weak number but if the goal in its day was to make a 348C cheater motor then stealth is the order of the day and the 265 is welcome and would not alarm the scrutineers.

Here is the future! You guys need to look into this. Could it be this simple?

http://ukm.academia.edu/TaibIskandarMohamad/Papers/322367/The_Combustion_and_Performance_of_a_Converted_Direct_Injection_Compressed_Natural_Gas_Engine_using_Spark_Plug_Fuel_Injector

DaveHelms drop all the projects we need 100% of you attention right here right now!

 

This is a project that is extremely interesting and looks to be growing some legs... Only on FChat!

 

Vince, for goodness sakes quit using that word "Legal" in any sense. With you and Plugzit in cahoots on anything, the word doesnt belong on as much as the same page! CA Legal..... be real, all they allow is pedals, you cant hardly even raise the CR or you fail NOX.

Nope, I know little to nothing about that engine but assure you that it came in a Roush box, it is still out in my trailer. Rest assured, it is a cheater engine in some respect but I never had a need to pull it apart to see 'how'. That was given to me in a big wooden box after a missed shift took out the IMSA Enduro engine we were running in that car. That is why the injectors, harness and the likes were all the same as the IMSA car. At one time in the distant past, both cars were owned by the same team and shared parts. Years later the same situation held true with both being stable mates and parts interchanged once again. I remember sliding a new cam belt on it, pulling all the ancillaries off the Enduro engine that came out and put them on that one. One afternoon spent at PPIR sorting and tuning is the total time on that engine prior to you obtaining it.

 

Bruce put you up to that... didnt he? That is the tactic he has used to keep me from finishing my projects..... always has me chasing the end all...... and it has worked! He is terrified of being the only one with parts spread out over two Counties but with no car that actually runs, misery loves company.

Last winters plan was to build the Enduro engine to run peanut alcohol/Nitro as then I could also run McDonalds frenchfry oil if Bruce cut the output of his Still.... It being 'Green' and my shop being in the Peoples Republic of Boulder... I am close enough with the current CR to actually pull that off.

CNG has always interested me but I never came to grips with mounting the drivers seat to a big pressure tank full of something that goes Boom, the roll cage I would build would weigh as much as the car itself! That aside, there are two new Bosch DI injectors sitting atop a scrap 308 2v head back by the mill. Kris keeps prodding me to put her engine together, and she doesnt care if its stock. She also knows me well enough to be certain what ever I build will be a test mule for some lame idea.

 

I haven't put FBB or anyone else up to anything when it comes to you.

You don't have to tell the world about my ever increasing stock pile of 355 parts and the fact that I, as of yet, I have No running cars...atleast we have one thing in common..lol

You are always blaming me for your inability to stay focused....
As for chasing the end all buddy???????....you've got me out chasing a donkey as we speak.

I'm ending this by saying that my brew is 99.999% alcohol with the addition of fresh whole strawberries....when you're stuck on the backside with a blown engine you can put a straw in the gas tank and all your worries magically dissappear...try that with CNG.


Now quit the whining and get off your politically correct *** and get those new injectors finished.

 

Sema?? I need a pass.

 

You should know that dyno numbers are not absolutes, but relative. I can say that the 355 engine pulls more hp no matter what we have done so far to the 348 engine. Now if we could safely run it up to 8500 rpm...

 

I have been told that I am mistaken in my recollection and since I wasn't at the dyno (a Dynopak, IIRC), I guess that's right.

Still my point is that you are not going to wave a magic wand at a Ferrari engine and find much power. It will take more cash than most of us want to spend or ability that most of us do not have. As a friend from the South likes to say the easiest power to find is by losing weight in the car.

 

Fruit and veggies...good for you, at your age these are a must. Focus now....

 

I've been throwing around the idea of upgrading the TB's on my 300ZX Twin Turbo but at $400 a set I wanted to try something on my own.

We recently purchased a CNC lathe at work so I finally got my chance. I opened up a pair of stock TBs from 50mm to 54mm. I machined new throttle plates out of stainless steel with a 7 degree taper to seal properly. It's hard to tell from the pics but there is a nice 8" radius taper from the inlet to the throttle plate area, it starts at about 58mm and tapers down to 54mm. I still need to flow test these against a stock TB but I expect decent gains in CFM. If it looks promising I will start producing these and selling them to the Z community on a core-exchange basis.

I am willing to take a shot at a set of 348 TBs to see how much material can be safely removed. Anyone want to volunteer?




Rob
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Likely me!

 

I think Vince and Goth did something similar along with raising the plenum but only came up with small increases. However, I could be wrong. Maybe they'll chime in. Ernie did some of this as well. Results always seemed muddy. Best of luck.

 

I'd be interested to know how small of increases and how much the plenum was raised.

 

We did raise the plenum in Vince's 348 which moves torque to a slightly higher RPM along with a 2mm increase in the TB size. The gains from that were only about 5-ish RWHP, not much but indeed a change. However that mod alone was dyno'd using the stock exhaust. When we went to a free flow exhaust, the numbers went up further ...... but we sadly used 400 cell cats, so the gains at that point were just shy of 20 RWHP.

After flow bench testing the 400 cell vs 200 cell cats the flow delta was significant. So the next step would be to go with 200 cell cats. That change, according to the flow numbers, should get Vince's 348 to about 25-28 RWHP gains over stock 348SS numbers. Hope this helps

 

Thanks. That direction seems like the way to go for those looking at boost down the road.

 

I'll do it.

 

So Bruce and Ernie get to fight over the first pair. One (or both) of you can send me a pair or just one and I can take some measurements and see how big they can go.


I'm excited for this project and I don't even have a 348.



Rob


I machined the throttle shaft to increase the overal area of the TB.
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PM me your address, I'll have them shipped out Monday.