Flat Slide Throttle Bodies
11-04-2013, 11:42 AM
#18
Race Car
Join Date: Mar 2012
Location: Austin TX, drinking beer in the garage
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Didn't the unobtanium JME intake use 4 slide valves? It was said to have poor part throttle driveability.
I just found this
http://rothsport-racing.com/Products...ide-Valve.html
I just found this
http://rothsport-racing.com/Products...ide-Valve.html
Last edited by Dougs951S; 11-04-2013 at 12:01 PM.
11-04-2013, 11:50 AM
#19
Three Wheelin'
Join Date: Feb 2007
Location: Indianapolis,IN
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The specific brand I'm working with come in 32 and 35 openings. Its a super simple, somewhat crude device. It's on an VW based aircraft engine (80HP). Tuning it is unlike anthing I've done in the past. A tapered needle fixed to the slide is pulled out of a hole allowing fuel to flow in proportion (roughly) to slide opening. The amount of fuel available to this hole is contolled by a "mixture" lever in the cockpit. Crude as hell, but uber-simple.
Not really a 951 type thing, but a 944 owner could get a few of these and start welding...
Not really a 951 type thing, but a 944 owner could get a few of these and start welding...
11-04-2013, 04:00 PM
#20
Three Wheelin'
To start I found these in another thread that was locked. They were intriguing and posted by Raceboy.
I saw those and though way back to my motorcycle days with carbs.
One way to increase performance of carbed sport bikes was to add flat slide carbs.
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The flat slides basically go rid of all the flow restrictions from the throttle butterfly. They made good power but because of a mechanical linkage (as opposed to vacuum) they could be instantly opened and if opened too fast, would bog the engine.
But it seems the estonian flatslides would solve some neat issues with 951s. They take up almost no space putting the "butterfly" as close to the valve as possible seems like it would help with throttle on a turbo.
It seems they are likely made from black anodized aluminum.
Any more info on these?
Lets not turn this one into a peeing match. It seems like a neat idea.
I saw those and though way back to my motorcycle days with carbs.
One way to increase performance of carbed sport bikes was to add flat slide carbs.
The flat slides basically go rid of all the flow restrictions from the throttle butterfly. They made good power but because of a mechanical linkage (as opposed to vacuum) they could be instantly opened and if opened too fast, would bog the engine.
But it seems the estonian flatslides would solve some neat issues with 951s. They take up almost no space putting the "butterfly" as close to the valve as possible seems like it would help with throttle on a turbo.
It seems they are likely made from black anodized aluminum.
Any more info on these?
Lets not turn this one into a peeing match. It seems like a neat idea.
Not sure if this is something I want on my 951, Id rather just have a bunch of torque from 3500rpm and up...
11-04-2013, 08:03 PM
#21
Addict
Rennlist Member
Rennlist Member
Didn't the unobtanium JME intake use 4 slide valves? It was said to have poor part throttle driveability.
I just found this
http://rothsport-racing.com/Products...ide-Valve.html
I just found this
http://rothsport-racing.com/Products...ide-Valve.html
11-05-2013, 05:42 AM
#23
Three Wheelin'
It can easily be cured when coupled with drive-by-wire throttle. It was not available back in the day and seeing how automotive OEM's squeeze the expenses down today, we probably will never see it even in high-dollar car.
But most of the "driveability issues" come down to the ECU/tuners ability. I hear all the time that ITB's cannot have good driveability let alone ITB's in boosted applications. Yet I have tuned my race-car to have pretty much street driveability at very low engine speeds and throttle openings, also with my friends 993 Carrera and he is very picky about driveability (standing in rush hour traffic makes people such)
It requires "4D" fuel mapping ability from ECU: Alpha-N (rpmxTPSxVE value) +MAP compensation because 30% TPS can have very different load.
But most of the "driveability issues" come down to the ECU/tuners ability. I hear all the time that ITB's cannot have good driveability let alone ITB's in boosted applications. Yet I have tuned my race-car to have pretty much street driveability at very low engine speeds and throttle openings, also with my friends 993 Carrera and he is very picky about driveability (standing in rush hour traffic makes people such)
It requires "4D" fuel mapping ability from ECU: Alpha-N (rpmxTPSxVE value) +MAP compensation because 30% TPS can have very different load.
11-05-2013, 06:41 PM
#24
Race Car
I've got these I don't need from an old back burner project,
Don't have them close at hand but I think I remember them being 45mm throat.
Also have mandrel aluminum 90's of the same I.D., trumpets and a 944T intake cut with just enough original runner to weld the mandrel 90's up that would place the throttle bodies horizontal.
Keeps factory fuel injector and fuel rail setup, would need a plenum and conversion to MAP.
Converting car to SP3 or E PCA configuration but we currently race 944 NA SP2s so I have no need for this stuff.
Just sold the 968 6 speed to another Rennlister but turbo and DTAFast Standalone, harness (w/ all 944T connectors), crank pulley 36/2 and turbocharger in pic can go too.
Have other pics of TBs.
T
Don't have them close at hand but I think I remember them being 45mm throat.
Also have mandrel aluminum 90's of the same I.D., trumpets and a 944T intake cut with just enough original runner to weld the mandrel 90's up that would place the throttle bodies horizontal.
Keeps factory fuel injector and fuel rail setup, would need a plenum and conversion to MAP.
Converting car to SP3 or E PCA configuration but we currently race 944 NA SP2s so I have no need for this stuff.
Just sold the 968 6 speed to another Rennlister but turbo and DTAFast Standalone, harness (w/ all 944T connectors), crank pulley 36/2 and turbocharger in pic can go too.
Have other pics of TBs.
T
